MN www.mn-net.com Ready-to-use layers for TLC Ready-to-use layers for TLC Summary of MN ready-to-use layers for TLC 273 Quality? – We are our most crucial critics! Due to a stringent production control we can guarantee the continuous high quality of our TLC plates and sheets. Thus our ready-to-use layers are subjected to standardised lot tests. The surface of the layer is checked for roughness or cracks in incident and UV light. Additionally, the hardness and adherence of the layer is checked by developing the plates in solvents of very different polarities. Ready-to-use layers for TLC / HPTLC Thin layer chromatography is used for a wide range of analy- ses, and over the years it has become apparent, that there is no universal plate which meets all possible demands. For this reason our range of TLC ready-to-use layers is very ver- satile to cover many different types of applications. Our ready-to-use layers offer several advantages: They are immediately ready for chromatographic se- paration. Tedious coatings or impregnations are not necessary. They have homogeneous, smooth, well adhering layers, an important criterion especially for reproducible quantitative evaluation. Adsorbents used for MACHEREY-NAGEL ready-to- use layers for TLC The adsorbent used most frequently in TLC is silica 60 (mean pore diameter 60 Å = 6 nm). About 80% of all TLC separations are performed with this separation medium. Oth- er customary adsorbents are aluminium oxide and cellulose. Kieselguhr, ion exchangers and polyamide complete the pic- ture of classical adsorbents. Later on, derived from high per- formance liquid chromatography (HPLC) reversed phases were introduced, mainly C 18 (octadecyl) modified silica. A highlight of stationary phase development was production and commercialisation of a TLC glass plate for enantiomer separation in 1985 by MACHEREY-NAGEL (CHIRAL- PLATE). Now ready-to-use layers with cyano-, amino-, diol and RP-2 modified silica coatings are also available. Special layers for specific separation problems complete our versa- tile range of TLC plates. In addition to the type of adsorbent its particle size distribu- tion and the thickness of the layer are important. For the standard silica plate the particle size is between 5 and 17 μm. The thickness of the layer is 0.25 mm for analytical plates. The same adsorbent is used for preparative layers of 0.5 mm and 1 mm thickness, while for 2 mm layers a slightly coarser material is used. For high performance thin layer chromatography (HPTLC) 0.2 mm layers with a mesh size of 2 – 10 μm are applied. While for silica preparative layers up to 2 mm are possible, layer thickness is limited to 0.5 mm for cellulose and 1 mm for aluminium oxide. Almost all of our ready-to-use layers are available with or without fluorescent indicator. Electron microscope photograph of a cross section through a glass plate with silica layer magnification x 500 Electron microscope photograph of a cross section through an aluminium sheet with silica layer magnification x 500
Transcript
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Summary of MN ready-to-use layers for TLC
273
Quality? – We are our most crucial critics!
Due to a stringent production control we can guarantee thecontinuous high quality of our TLC plates and sheets. Thusour ready-to-use layers are subjected to standardised lottests. The surface of the layer is checked for roughness orcracks in incident and UV light. Additionally, the hardnessand adherence of the layer is checked by developing theplates in solvents of very different polarities.
Ready-to-use layers for TLC / HPTLC
Thin layer chromatography is used for a wide range of analy-ses, and over the years it has become apparent, that there isno universal plate which meets all possible demands. Forthis reason our range of TLC ready-to-use layers is very ver-satile to cover many different types of applications.Our ready-to-use layers offer several advantages:
They are immediately ready for chromatographic se-paration. Tedious coatings or impregnations are notnecessary.They have homogeneous, smooth, well adheringlayers, an important criterion especially for reproduciblequantitative evaluation.
Adsorbents used for MACHEREY-NAGEL ready-to-use layers for TLC
The adsorbent used most frequently in TLC is silica 60(mean pore diameter 60 Å = 6 nm). About 80% of all TLCseparations are performed with this separation medium. Oth-er customary adsorbents are aluminium oxide and cellulose.Kieselguhr, ion exchangers and polyamide complete the pic-ture of classical adsorbents. Later on, derived from high per-formance liquid chromatography (HPLC) reversed phaseswere introduced, mainly C18 (octadecyl) modified silica. A highlight of stationary phase development was productionand commercialisation of a TLC glass plate for enantiomerseparation in 1985 by MACHEREY-NAGEL (CHIRAL-PLATE). Now ready-to-use layers with cyano-, amino-, dioland RP-2 modified silica coatings are also available. Speciallayers for specific separation problems complete our versa-tile range of TLC plates.In addition to the type of adsorbent its particle size distribu-tion and the thickness of the layer are important. For thestandard silica plate the particle size is between 5 and17 µm. The thickness of the layer is 0.25 mm for analyticalplates. The same adsorbent is used for preparative layers of0.5 mm and 1 mm thickness, while for 2 mm layers a slightlycoarser material is used. For high performance thin layerchromatography (HPTLC) 0.2 mm layers with a mesh size of2 – 10 µm are applied.While for silica preparative layers up to 2 mm are possible,layer thickness is limited to 0.5 mm for cellulose and 1 mmfor aluminium oxide. Almost all of our ready-to-use layers are available with orwithout fluorescent indicator.
Electron microscope photograph of a cross section through a glass plate with silica layer
magnification x 500
Electron microscope photograph of a cross section through an aluminium sheet with silica layer
magnification x 500
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Summary of MN ready-to-use layers for TLC
274
Code Layer Page
Standard silica
ADAMANT silica 60 with improved binder system and optimized particle size distribution 278
SIL G silica 60, standard grade 278
DURASIL silica 60, special binder system 278
SIL N-HR high purity silica 60, special binder system, higher gypsum content 278
SILGUR silica 60 with kieselguhr concentrating zone 279
Unmodified silica for HPTLC
Nano-SILGUR nano silica 60, particle size 2 – 10 µm, with kieselguhr concentrating zone 279
Nano-ADAMANT nano silica 60, optimised binder system and particle size distribution 281
Nano-SIL nano silica 60, standard grade 281
Nano-DURASIL nano silica 60, special binder system 281
AMD SIL nano silica 60, extremely thin layer for AMD procedure 281
Modified silica for HPTLC
Nano-SIL C18-50/C18-100 nano silica with partial or complete C18 modification 282
RP-18 W/UV254 nano silica with partical octadecyl modification, wettable with water 284
CEL 400 microcrystalline cellulose MN 400 (AVICEL®) 289
CEL 300 DEAE dimethylaminoethyl-modified cellulose ion exchanger 290
CEL 300 DEAE/HR mixed layer of cellulose ion exchanger and high purity cellulose 290
CEL 300 PEI polyethyleneimine-impregnated cellulose ion exchanger 290
CEL 300 AC acetylated cellulose MN 300 291
Layers for special separations
POLYAMIDE-6 perlon = ε-aminopolycaprolactame 291
CHIRALPLATE RP silica coated with Cu2+ ions and chiral reagent, for enantiomer separation 292
SIL G-25 HR high purity silica 60 with gypsum, recommended for aflatoxin separations 294
SIL G-25 Tenside silica G with ammonium sulphate for separation of surfactants 294
GUR N kieselguhr 294
Nano-SIL PAH nano silica with special impregnation for PAH analysis 295
IONEX-25 SA-Na mixed layer of strongly acidic cation exchanger and silica 295
IONEX-25 SB-AC mixed layer of strongly basic anion exchanger and silica 295
ALOX/CEL-AC-Mix mixed layer of aluminium oxide and acetylated cellulose 296
SILCEL-Mix mixed layer of cellulose and silica 296
GURSIL-Mix mixed layer of kieselguhr and silica 296
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Summary of MN ready-to-use layers for TLC
275
Supports for TLC ready-to-use layers
The support used most often is the glass plate. It is resistantand easy to handle. Disadvantages are fragility, a relativelyhigh weight (glass plates are about 1.3 mm thick) and neces-sary additional packing material. Also the production costsfor coating glass plates are higher than for polyester or alu-minium sheets. For these reasons precoated glass platesare the most expensive ready-to-use layers for TLC.Polyester sheets (about 0.2 mm thick) – known under thetrade name POLYGRAM® precoated sheets – can be moreeconomically coated, since they can be manufactured in rollform. Other advantages are that polyester sheets are un-breakable, resistant towards all common solvents, need lesspacking and less shelf space for storage. Furthermore, theycan be cut with scissors into any required size, and spots canbe cut and eluted etc. Small sheets, such as 8 x 4 cm, can beeconomically manufactured and packed. Charring techniquescan be applied for silica coated POLYGRAM® sheets, howeverat somewhat lower temperatures than on glass. The maximumtemperature for POLYGRAM® sheets is 160 °C. Besides polyester aluminium sheets are used as supportfor TLC ready-to-use layers. We have considerably improvedour ALUGRAM® sheets. Because of a thicker aluminiumsupport (about 0.15 mm thick) they are much more stable
and easier to cut. Even a 20 x 20 cm ALUGRAM® TLC sheethas a torsional strength which is almost as good as for aglass plate. And for scanning, too, the background noise ofthe ALUGRAM® is about as low as for a glass plate. As withPOLYGRAM® the layers feature an outstanding adherence,which allows cutting of the sheets to any size desired withoutfracturing of the layer. For ALUGRAM® sheets a support ofplain aluminium foil is coated using the same binder systemas for our TLC glass plates. For eluents containing high con-centrations of water we recommend our POLYGRAM® pre-coated sheets. The binder system used for POLYGRAM®
sheets is absolutely stable in water. However, like POLYGRAM® precoated sheets, TLC glassplates and ALUGRAM® sheets can be sprayed or dipped withpurely aqueous visualisation reagents without damage to thelayer. With ALUGRAM® precoated sheets, problems mightarise when using eluents, which contain high concentrationsof mineral acids or concentrated ammonia (which attack thealuminium). In such cases we recommend using our glassplates or polyester sheets. Otherwise ALUGRAM® precoatedsheets offer the same advantages as POLYGRAM® sheets,however, with increased temperature resistance (e.g. for char-ring techniques).
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Standard silica · TLC ready-to-use layers
276
For years now many TLC separations are standardised forroutine investigations in analytical laboratories. Prerequisiteare TLC ready-to-use layers which give reproducible results.The following criteria must be met:
Our TLC glass plates and precoated sheets meet these re-quirements. For special applications today a number ofplates and sheets are available with special layers, which willbe described in detail in the following paragraphs.The standard silica coating is one of the most frequentlyused ready-to-use layers for TLC. For these plates we usesilica 60 with a mean pore diameter of 60 Å, a specific sur-face (BET) of about 500 m2/g, a specific pore volume of 0.75ml/g and a particle size of 5 to 17 µm. As fluorescent indica-tors we use manganese activated zinc silicate for short-waveUV light (254 nm) and a special inorganic fluorescent pig-ment for long wave UV light (366 nm).As binder highly polymeric products are used, which are sta-ble in almost all organic solvents and resistant towards ag-gressive visualisation reagents. The binder systems used forour POLYGRAM® precoated sheets are also completely sta-ble in purely aqueous eluents. The POLYGRAM® types SILG and SIL G/UV254 on one hand and the POLYGRAM®
types SIL N-HR and SIL N-HR/UV254 on the other hand havedifferent binder systems and thus show different separationcharacteristics. Another special feature of the POLYGRAM®
SIL N-HR is the higher gypsum content compared to SIL G.
DURASIL glass plates for TLC
DURASIL is a family of precoated glass plates with unmodi-fied silica. It is available in two types as DURASIL-25 for TLCand Nano-DURASIL-20 for HPTLC (for HPTLC plates seethe next chapter from page 279). DURASIL plates differ fromthe well-known plates SIL G-25 and Nano-SIL G-20 by aspecial binder system, which results in hard, water-resistantand wettable layers with outstanding separation propertiesand distinct different selectivities. Like our proven TLC glass plate SIL G-25, DURASIL-25 iscoated with unmodified silica 60 . They are available with orwithout fluorescent indicator (green fluorescence, 254 nm). DURASIL-25 plates show superior separation characteristicsin the fields of environmental, clinical, medical and organicanalyses. Substances separated so far include
For more applications of DURASIL ready-to-use plates,check our application database on the internet.
ADAMANT glass plates for TLC
In addition to the layers SIL G and DURASIL MACHEREY-NAGEL presents another generation of glass plates with sili-ca layers for TLC. ADAMANT plates feature a specially developed binder sys-tem, which results in an outstanding hardness of the silicalayer. Due to the enormous abrasion resistance the forma-tion of dust on the surface of the ADAMANT is minimised. The following advantages result:
Outstanding hardness of the layer due to an optimisedbinder system: the plate can be easily labelled, e.g. witha lead pencil for clear identificationHigh abrasion resistance of the surface, no formationof dust: a dust-free plate allows convenient handlingand avoids silica contamination of the TLC chamberVery well suited for trace analysis: the UV indicator ofthe ADAMANT features an increased brilliance which, incombination with the low-noise background, results in anincreased detection sensitivity. Increased separation efficiency: compared to mostcommonly used plates on the market, ADAMANT showsimproved separation efficiency, because the particle sizedistribution of the silica has been optimized, resulting ina higher number of theoretical plates. The selectivity ofADAMANT is different compared to Sil G or DURASIL.Thus the chromatographer now can choose from 3 dif-ferent types of MN plates in order to optimise a givenseparation.
In the figure below, the Rf values of four different flavonoidsfrom the MN batch test are compared. This batch test is partof the regular quality control, which shows the highest repro-ducibility from batch to batch and layer to layer.
Batch-to-batch reproducibility of ADAMANT platesRf
batch no.quercetinhyperosidechlorogenic acidrutin
1 2 3 4 5 6
1,0
0,8
0,6
0,4
0,2
0,0
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Standard silica · TLC ready-to-use layers
277
Separation of steroids on ADAMANT UV254 and SIL G/UV254
Eluent: chloroform/methanol (97:3)Developing time: 10 minutes0.1 % solution in chloroform
Rf ADAMANT SIL G
Cortisone 0.37 0.27Corticosterone 0.43 0.30Testosterone 0.50 0.39Deoxycorticosterone 0.55 0.46Progesterone 0.73 0.62Migration distance 5.0 cm 5.7 cm
ADAMANT UV254 SIL G/UV254
4029
30
Separation of pain relievers
Layer: ADAMANT UV254 Eluent: chloroform/ethyl acetate (1 : 1, v/v)Migration distance:70 mm in 20 minutesSample volume: 1 µl
SIL G-25 0.25 mm 809017* 809011 809012 809013SIL G-25 UV254 0.25 mm 809027* 809021 809020 809022 809023SIL G-25 UV254+366 0.25 mm 809121 809122 809123
20/packSIL G-50 0.50 mm 809051SIL G-50 UV254 0.50 mm 809053
15/packSIL G-100 1.00 mm 809061SIL G-100 UV254 1.00 mm 809063
12/packSIL G-200 2.00 mm 809073SIL G-200 UV254 2.00 mm 809083POLYGRAM® polyester sheets
50/pack 50/pack 25/pack 25/packSIL G 0.20 mm 805032 805012 805013 805014SIL G/UV254 0.20 mm 805021 805022 805023 805024SIL G/UV254 0.20 mm Roll 500 x 20 cm 805017
SIL G 0.20 mm 818030.20 818161 818032 818163 818033SIL G/UV254 0.20 mm 818131 818130.20 818160 818132 818162 818133
DURASIL silica 60 as above, however, with special binder system
Glass plates50/pack 100/pack 50/pack 25/pack
DURASIL-25 0.25 mm 812003 812004DURASIL-25 UV254 0.25 mm 812005* 812006 812007 812008
SIL N-HRhigh purity silica 60 as above, however, with special binder system and higher gypsum content
POLYGRAM® polyester sheets50/pack 25/pack
SIL N-HR 0.20 mm 804012 804013SIL N-HR/UV254 0.20 mm 804022 804023For plates SIL G-HR for aflatoxin separation please see page 294.
* for bigpacks with 200 plates add .200 at the end of the catalogue number.
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Standard silica · TLC ready-to-use layers
279
Concentrating zone · glass plates
Glass plates with concentrating zone are available asSILGUR-25 with standard silica coating and as high perform-ance TLC plate Nano-SILGUR-20.
Silica layers with concentrating zone take advantage of thecompletely different adsorption properties of two customarychromatographic adsorbents in one plate. Contrary to silicathe concentrating zone of kieselguhr is completely inert, withrespect to adsorption, towards a large number of compounds. The sample to be separated is applied to the concentratingzone and developed with a suitable eluent; irrespective ofshape, size or position of the spot, the samples always forma narrow band at the interface of the two adsorbents, i.e.kieselguhr and silica. Separation then begins at this point.With identical samples the separated substances always ap-pear at the same height, as illustrated by the figures above. The concentrating zone serves as a "quick application zone",which allows quantitative evaluation of chromatograms, evenif samples have been applied with an unsteady hand. Sincecareful sample application is time-consuming or requiresspecial equipment, silica plates with concentrating zone arereal time-savers. This includes economy in preparation timebecause of a reduction in evaporation time: larger volumes ofdilute solutions can be applied instead of smaller quantitiesof concentrated solutions. This is often of advantage espe-cially in biochemical investigations.
Ordering information
Nano silica · HPTLC ready-to-use layers
In addition to our TLC ready-to-use layers with standard silicacoating we manufacture high performance ready-to-use layersunder the name "nano silica". We use the same silica 60which has been successfully applied in thin layer chromatog-raphy for about thirty years, however, the adsorbent, as inHPLC, is narrowly fractionated. We use mean particle sizes of2 – 10 µm, and these allow theoretical plate heights, which are1 order of magnitude smaller than on standard silica layers.Advantages of the nano ready-to-use layers compared tostandard silica layers are
sharper separations due to small particle size and nar-row fractionation. Theoretical plate heights (h values) areconsiderably smaller than those of the standard TLC
plate. In addition diffusion and – as a consequence –band broadening are much lower.shorter developing times and shorter migration dis-tances. After only a few centimeters an optimal separa-tion is achieved.smaller samples of 0.01 – 0.1 µl (10 – 100 nanoliters).The samples applied are considerably smaller than withstandard plates, thus it is possible to apply a largenumber of samples to a very small surface area, withoutsamples interfering with each other.increased detection sensitivity (nanogram level,hence nano plate). With fluorescence evaluation pico-gram quantities can be detected.
arbitrary application of samples in a
developed
concentrating zonechromatogram
Designation Thickness of layer
Plate size [cm] Fluores-cent
indicator10 x 10 10 x 20 20 x 20
25 / pack 50 / pack 25 / pack
SILGUR plates with concentrating zonesilica 60 with kieselguhr zone for rapid sample application
Glass platesSILGUR-25 0.25 mm 810012 810013 –SILGUR-25 UV254 0.25 mm 810022 810023 UV254
Nano-SILGUR plates with concentrating zoneNano silica 60 with kieselguhr zone for rapid sample application
Glass plates Nano-SILGUR-20 0.20 mm 811032 –Nano-SILGUR-20 UV254 0.20 mm 811042 UV254
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Nano silica · TLC ready-to-use layers
280
The layer consists of silica 60 with a mean pore size of 60 Å,specific surface of 500 m2/g, a specific pore volume of0.75 ml/g, but a mean particle size of only 2 – 10 µm. As flu-orescent indicator we use manganese activated zinc silicatefor short-wave UV light of 254 nm. As binder we add a highlypolymeric product, which is stable in almost all organic sol-vents and towards aggressive visualisation reagents. Ready-to-use aluminium sheets ALUGRAM® with nano grade silica Ready-to-use layers with aluminium support, measuring5 x 20 or 20 x 20 cm, are available for HPTLC, too. Theselayers combine the advantages of the nano silica with the ad-vantages of the support aluminum.
DURASIL glass plates for HPTLC
Similar to the DURASIL plates with standard silica we alsoproduce HPTLC plates Nano-DURASIL with nano silica(mean pore diameter 60 Å, pore volume about 0.75 ml/g,specific surface 500 m2/g, particle size 2–10 µm). Nano-DU-RASIL plates differ from the well-known plates Nano-SIL G-20 by the binder system, which results in hard, water-resist-ant and wettable layers with outstanding separation proper-ties. Nano-DURASIL plates are available with or without fluo-rescent indicator (green fluorescence, 254 nm).
Nano-ADAMANT glass plates for HPTLC
If one compares the performance of the Nano-ADAMANTplates with the alternative MN plates, one observes for manyseparations different selectivity patterns. Differences in the characteristics of ADAMANT plates com-pared to conventional silica plates are described in detail inthe chapter “Standard silica layers” on page 276.Nano-ADAMANT plates show superior separation character-istics in the fields of environmental, clinical, medical and or-ganic analyses. Substances separated so far include an-thraquinone dyes, pesticides, food dyes of the E series,analgesics, barbiturates, flavonoids in accordance with DAB,vitamins and tocopherols. For more applications see our ap-plication database on the internet. Compared to standard ADAMANT plates Nano-ADAMANTplates offer faster separations with better resolution andequal selectivity, maintaining the advantages of the ADA-MANT as described above:
brilliant UV indicatorexcellent hardness and easy labelling
AMD plates
Nano plates with extremely thin layers of silica 60 (0.05 or0.1 mm thick) can be used for conventional HPTLC, but areespecially suited for the AMD procedure (AMD = AutomatedMultiple Development), which is explained in this chapter. Rapid and efficient analyses at ultra trace levels requiremethods, which allow simultaneous investigation of severalactive ingredients in a large number of samples. Such multi-
methods considerably increase the sample throughput andthus lower the cost per analysis. The TLC / AMD procedure, which has been developed by theCentral Analytical Department of the Bayer AG, Dormagen,Germany, allows the simultaneous determination of 40 plantprotective chemicals from 14 extracts on one TLC plate 1).
Comparison of ADAMANT and Nano-ADAMANT plates
Separation of anthraquinone dyesLayers: A) ADAMANT
B) Nano-ADAMANTSample: 1 µl, about 0.1%Eluent: toluene – cyclohexane (4:3, v/v)Migration time: A) 30 min, B) 15 minPeaks:1. Blue 32. Violet 23. Red4. Green5. Blue 16. Greenish blue7. Violet 1
1
2
34
5
67
10 20 30 40 50 mm
10 20 30 40 mm
1
2
3 4 5
67
A) ADAMANT
B) Nano-ADAMANT
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Nano silica · TLC ready-to-use layers
281
Principle:Compared to conventional multiple development of TLCplates, in which the total migration distance is passed severaltimes, an AMD development is performed in many partialsteps of different length, the number of individual runs beingbetween 10 and 30. The migration distance of each step is,
by a defined increment, longer than the previous step. Ingeneral, these increments are between 1 and 3 mm. Be-tween all steps, the TLC plate is dried in vacuum 1).For more information concerning the AMD procedure pleaserefer to the references cited below.For production of the nano plates with extremely thin layerwe use the same nano silica 60 with mean pore size of 60 Å,a specific surface of 500 m2/g, a specific pore volume of0.75 ml/g and a mean particle size of only 2 – 10 µm. A man-ganese-activated zinc silicate for short-wave UV light of254 nm is used as fluorescent indicator. The binder is a high-ly polymeric product, which is resistant in almost all organicsolvents and towards many aggressive detection reagents.The support of the plate is glass.References1) K. Burger, Pflanzenschutz-Nachrichten-Bayer 41,2 (1988)
1732) J. A. Perry, K. W. Haag and L. J. Glunz, J. Chromato-
graphic Science 11 (1973) 4473) T. H. Jupille, J. A. Perry, J. Chromatography 99 (1974) 2314) T. H. Jupille and J. A. Perry, Science 194 (1976) 2885) K. Burger, Fresenius Z. Anal. Chem. 318 (1984) 228
Ordering information
0 10
AMD
conventional TLCPeak height
Migration distance in cm
Designation Thick-ness of layer
Plate size [cm] Fluores-cent in-dicator
5 x 5 5 x 20 10 x 10 10 x 20 20 x 20100 / pack 50 / pack 25 / pack 50 / pack 25 / pack
Nano-ADAMANT silica 60, specific surface (BET) ~ 500 m2/g, mean pore size 60 Å,
specific pore volume 0,75 ml/g, particle size 2 – 10 µm, optimised binder system and particle size distribution
Glass platesNano-ADAMANT-20 UV254 0.20 mm 821100 821110 821120 UV254Nano-ADAMANT-20 0.20 mm 821130 821140 821150 –
Nano-SIL nano silica as above, standard quality
Glass platesNano-SIL-20 0.20 mm 811011 811012 811013 –Nano-SIL-20 UV254 0.20 mm 811021 811022 811023 UV254
ALUGRAM® aluminium sheetsNano-SIL G 0.20 mm 818140 818141 –Nano-SIL G/UV254 0.20 mm 818142 818143 UV254
Nano-DURASIL Nano silica as above, however, with special binder system
Glass platesNano-DURASIL-20 0.20 mm 812010 812011 –Nano-DURASIL-20 UV254 0.20 mm 812012 812013 812014 UV254
AMD SILsilica 60, specific surface (BET) ~ 500 m2/g, mean pore size 60 Å, specific pore volume 0.75 ml/g, particle size 2 – 10 µm
Glass plates with extremely thin nano silica layerAMD SIL G-05 UV254 0.05 mm 5 / pack 811101 UV254AMD SIL G-10 UV254 0.10 mm 25 / pack 811103 UV254
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
TLC and HPTLC plates with modified silica layers
282
C18 HPTLC ready-to-use layers with RP silica TLC ready-to-use layers coated with hydrophilic silica havebeen in use for a number of years, and the majority of all TLCseparation problems can be solved with these layers.However, it can be advantageous to make certain separa-tions on lipophilic silica layers, i.e. in reversed phase. Due tothe rapid development of HPLC there is an increasing de-mand for TLC plates which can be used for orienting pre-separations. In HPLC frequently reversed phase systemsbased on C8 or C18 silanized silicas are used. These systemsare especially suited for the separation of very polar (hy-drophilic) classes of compounds, which previously could onlybe separated by ion exchange chromatography. RPTLC withalkyl silanised silicas as stationary phases considerablybroadens the applicability of TLC.
HPTLC plates Nano-SIL C 18-50 and Nano-SIL C 18-100
After careful consideration we have decided, that instead ofthe different alkyl silanes used in HPLC (e.g. C2, C4, C8 orC18) we use only C18 silane for our reversed phase TLCplates, but with different percentages of silanisation. Practi-cal experience has confirmed the validity of our considera-tions. For a dimethyl modified silica layer see page 284.Our RP plates are produced using a medium pore size silica(mean pore diameter 60 Å), with a mean particle size of 2 –10 µm (identical to the material used for our nano silicaplates). This nano silica is reacted to a different degree, ei-ther totally (= 100%) or partially (= 50% of the reactivegroups). Thus we meet a broad range of applications: anhy-drous eluents as well as eluents with high concentrations ofwater can be used (see table).As fluorescent indicator we use an acid-resistant productwhich allows application of strongly acidic eluents withoutundesirable fluorescence quenching. This fluorescence indi-cator shows a pale blue fluorescence in short-wave UV light.UV absorbing substances appear as dark-blue to black spotson a light-blue background.The two available layers differ by their selectivity, possiblydue to a combination of hydrophobic and polar interactions.Furthermore, of course they show different wettability (hydro-phobicity). The table shows migration distances for differentcontents of water.
Substances separated on Nano-SIL C 18-50 and Nano-SIL C 18-100 include the following classes:
Nano-SIL C 18Nano silica with octadecyl modification (RP-18), degree of silanisation 100 % for C 18-100, 50 % for C 18-50
Glass platesNano-SIL C 18-50 } 50 % silanised
0.20 mm 811054 –Nano-SIL C 18-50 UV254 0.20 mm 811064 UV254Nano-SIL C 18-100 } 100 % silanised
0.20 mm 811052 –Nano-SIL C 18-100 UV254 0.20 mm 811062 UV254
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
TLC and HPTLC plates with modified silica layers
283
C18 HPTLC ready-to-use layers with RP silica RP-18 W/UV254 . a wettable HPTLC plate for re-versed phase and normal phase chromatography
The TLC glass plates RP-18 W/UV254 are “hybrid” plates forreversed phase (RP) as well as for normal phase (NP) chro-matography. Formerly, TLC plates were either reversedphase plates with totally hydrophobic layer, e.g. Nano-SIL C18-100, or normal phase plates with totally hydrophilic layer,e.g. SIL G-25.TLC plates RP-18 W/UV254 can be developed with purely or-ganic and organic/aqueous solvents as well as with purelyaqueous eluents. A partially silanised C18 silica with definednumber of residual silanol groups allows a more "RP type” or“NP type” separation depending on eluent composition. Thusthe polarity of the layer can be determined by the relative po-larity of the eluent. These plates can be used with acid elu-ents as well, because the layer contains an acid-resistant flu-orescent indicator. The mean particle size of the silica is9 µm.So far the following classes of compounds could be separat-ed successfully on RP-18 W/UV254:
Activation of the layer at 110 – 115 °C for 10 – 15 min oftenimproves the separation.
Developing time for a migration distance of 7 cm versus eluent composition for the system
a) RP-18 W/UV254 b) Nano-SIL C 18-50 UV254c) Nano-SIL C 18-100 UV254
Developing time for a migration distance of 7 cm versus eluent composition for the system
a) RP-18 W/UV254 b) Nano-SIL C 18-50 UV254c) Nano-SIL C 18-100 UV254
acetonitrile/water on different RP plates:
methanol/water on different RP plates:
0 20 40 60 80 100 % acetonitrile
70
60
50
40
30
20
10
0
0 20 40 60 80 100 % methanol
Dev
elop
ing
time
[min
]
70
60
50
40
30
20
10
0
c)
b)
a)
a)
b)
c)
Elution properties of different RP plates in mixtures of methanol/water and acetonitrile/water
of varying compositions
Dev
elop
ing
time
[min
]
Separation of salicyl derivativesLayer: ALUGRAM® RP-18 W/UV254Sample volume: 250 nlEluent: methanol / 1 N acetic acid (25:75, v/v)Migration distance: 9 cm in 30 minDetection: TLC scanner, UV 254 nmPeaks:1. Salicylic acid (1.0%)2. Acetylsalicylic acid (1.0%)3. Salicyluric acid (0.4%) 1.200
0.800
0.400
0.000
9.0 50.0
1
2
3
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
TLC and HPTLC plates with modified silica layers
284
C18 / C2 ready-to-use layers with RP silica ALUGRAM® RP-18 W/UV254 . the aluminium sheet for re-versed phase HPTLC This reversed phase ready-to-use aluminium sheets com-bine the advantages of our outstanding RP-18 W/UV254 layerwith those of the flexible support aluminium. Aluminium istemperature-resistant like glass, but features the advantages
of being nonbreakable, requiring less packaging and lowerstorage space. The outstanding adherence of the layer onthe support allows cutting of any size, simply with scissors,or cutting out interesting components after separation, mak-ing them available for subsequent investigations (e.g. IR,MS).
Ordering information
RP plates · RP-2/UV254 – silanised silica layer for TLCIn pharmacopoeias the RP-2 phase is called ”silanised sili-ca“, i.e. like in HPLC and SPE the term ”2“ stands for dime-thyl and should not be confused with ethyl. The silica usedfor production has a pore size of 60 Å and a particle size dis-tribution between 5 and 17 µm. The layer contains an acid-resistant indicator with a blue fluorescence at 254 nm. TheTLC plate RP-2/UV254 can be developed with purely organic,organic/aqueous and purely aqueous eluents. Thus thephase finds numerous applications in normal phase chroma-tography as well as in the reversed phase mode. Applica-tions include the analysis of active plant constituents andsteroids.
Ordering information
Designation Thickness of layer
Plate size [cm] Fluores-cent in-dicator
4 x 8 5 x 10 5 x 20 10 x 10 10 x 20 20 x 20
RP-18 W/UV254Nano silica with partial octadecyl modification (C 18), wettable with water
Glass platesRP-2/UV254 0.25 mm 811080 811081 811082 UV254
ALUGRAM® aluminium sheetsRP-2/UV254 0.15 mm 818170 818171 UV254
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
TLC and HPTLC plates with modified silica layers
285
CN Nano-SIL CN · the cyano-modified ready-to-use layer
For manufacturing this plate, again nano grade silica is used.The cyano modification results in plates with a somewhatmore hydrophobic character compared to the amino plate,with the following series of polarities: silica > DIOL > NH2 >CN > RP-2 > C 18-50 > RP-18 W > C 18-100. As with ourother plates, we use an acid-resistant indicator with a bluefluorescence at 254 nm. This neutral ready-to-use layer canbe wetted equally well with water as with organic solvents,thus the plate can be used with all conventional TLC eluents. Similar to the RP-18 W plate, Nano-SIL CN shows normalphase or reversed phase separation modes depending onthe polarity of the developing solvent.
The following figure illustrates the transition from the NPcharacter to the RP character for the example of steroids, inwhich the polarity of the eluent governs the type of separa-tion mechanism. If the separation is performed in pure petro-leum ether (PE), the steroids are strongly retained due to ad-sorptive interactions with the active sites of the stationaryphase. Logically, this effect is strongest for cortisone with itsfunctional groups. In the eluent system PE – acetone the re-tention of the steroids decreases with increasing acetonecontent. When the eluent consists of 50% acetone, all threesubstances are found more or less in the range of the solventfront. When changing the eluent system to acetone – water,the RP character of the Nano-SIL CN plate becomes evident.First of all the sequence of elution is reversed: the non-polarcholesterol is now more strongly retained than the more po-lar components. The presence of water increases the reten-tion of the three steroids. In addition to steroid hormones, al-so phenols and preservatives can be separated on Nano-SILCN. For detailed applications using the plates Nano-SIL CNplease see our applications database on the internet.
Ordering information
Separation of preservatives Layer: Nano-SIL CN/UVSample volume: 400 nlEluent: ethanol / water / glacial acetic acid
20:80:0.2 with 0.1 mol/l tetraethylammonium chloride
Migrationdistance: 7.3 cm in 30 minDetection: TLC scanner, UV 254 nm
Rf values of different steroids as a function of eluent compositionLayer: Nano-SIL CN
Designation Thickness of layer
Plate size [cm] Fluores-cent in-dicator
4 x 8 10 x 10 10 x 20 20 x 2050 / pack 25 / pack 25 / pack 25 / pack
Nano-SIL CN cyano-modied nano silica
Glass platesNano-SIL CN/UV 0.20 mm 811115 811116 UV254
ALUGRAM® aluminium sheetsNano-SIL CN/UV 0.15 mm 818184 818185 UV254
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
TLC and HPTLC plates with modified silica layers
286
NH2 Nano-SIL NH2 · the amino-modified ready-to-use layer The base material for this hydrophilic TLC ready-to-use plateis silica with a mean pore size of 60 Å and a mean particlesize of 2 – 10 µm, which is identical with the material used forour nano silica plates. The amino modification results in aneutral ready-to-use layer, which is wetted equally well bypure water as by organic solvents. Thus all conventional elu-ents used in chromatography can be applied without reser-vation. This layer is available with or without an acid-resistantfluorescent indicator. The Nano-SIL NH2 plate is well suited for the separation ofvitamins, sugars, steroids, purine derivatives, xanthines,phenols, nucleotides, and pesticides.
For detailed applications using the plates Nano-SIL NH2please see our application database on the internet.
Ordering information
** ** ** ** ** ** ** ** ** **
adenosinec-AMP
AMP
ADP
ATP
0 10 20 30 40 50 60 70 80 90 100 %MeOH
Rf1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
%H2O
01090 80 70 60 50 40 30 20100
Separation of adenosine, adenosine monophosphate (c-AMP, AMP), adenosine diphosphate (ADP) and ade-nosine triphosphate (ATP)Layer: Nano-SIL NH2/UVEluent: MeOH/H2O according to fig. + 0.18 M NaClMigration distance 7 cm
Separation of sugarsLayer: Nano-SIL NH2/UVEluent: ethyl acetate / pyridine / water /
glacial acetic acid (60:30:10:5, v/v/v/v)
Migration distance: 8 cm in 45 min, double develop-ment
Sample volume: 500 nlDetection: dry layer at 160 °C for 5 min,
4 x 8 10 x 10 10 x 20 20 x 2050 / pack 25 / pack 25 / pack 25 / pack
Nano-SIL NH2 amino-modified nano silica
Glass platesNano-SIL NH2 0.20 mm 811109 –Nano-SIL NH2/UV 0.20 mm 811111 811112 UV254
ALUGRAM® aluminium sheetsNano-SIL NH2/UV 0.15 mm 818182 818183 UV254
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
TLC and HPTLC plates with modified silica layers
287
Diol Nano-SIL DIOL/UV ·the diol modified layer for TLC
For production of this hydrophilic ready-to-use layers we use anano-grade silica (2 – 10 µm) with a mean pore size of 60 Å.The polarity of this phase is between that of silica and the NH2phase. As usual the layer contains the acid-resistance indicatorwith a blue fluorescence at 254 nm. The DIOL phase, too, canbe used with water or with organic solvents and can thus beused with all common TLC eluents. Depending on the condi-tions this plates can be operated in the reversed phase or thenormal phase mode. Applications include e. g. steroids, pesti-cides or plant constituents. Since it is less sensitive to the watercontent of the environment, the DIOL phase can be used as analternative to silica in critical separation problems.
Ordering information
HPTLC method development kits To facilitate selection of the optimum HPTLC plate for a givenseparation, we offer HPTLC method development kits.
tone (80 + 20, v/v)Migration distance: 7 cmDetection: TLC scanner, 238 nmPeaks: (0.07% each in MeOH)1. Metoxuron2. Monuron3. Metobromuron
4023
40
Designation Thickness of layer
plate size [cm] Fluores-cent in-dicator
4 x 8 10 x 10 10 x 20 20 x 2050 / pack 25 / pack 25 / pack 25 / pack
Nano-SIL DIOLdiol-modified nano silica
Glass platesNano-SIL DIOL/UV 0.20 mm 811120 811121 UV254
ALUGRAM® aluminium sheets Nano-SIL DIOL/UV 0.15 mm 818180 818181 UV254
Composition Cat. No.
Development kit with glass plates
3 glass plates 10 x 10 cm (scored to 5 x 10 cm) each of Nano-SIL C18-100/UV254, RP-18 W/UV254, RP-2/UV254,Nano-SIL CN/UV, Nano-SIL NH2/UV, Nano-SIL DIOL/UV
811001
Development kit with ALUGRAM® aluminium sheets
5 sheets 4 x 8 cm each of RP-18 W/UV254, RP-2/UV254, Nano-SIL CN/UV, Nano-SIL NH2/UV, Nano-SIL DIOL/UV
818001
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Aluminium oxide · TLC ready-to-use layers
288
For general information on aluminium oxide as adsorbent inTLC please refer to the chapter “Adsorbents in TLC” on page304. To ensure sufficient adherence an inert organic binderis added to the aqueous suspension for coating. The alumin-ium oxide has a specific surface of about 200 m2/g (BET)and a pore size of about 60 Å. We recommend to activate aluminium oxide ready-to-use layers before use by heating 10 minutes at 120 °C
Ordering information
Separation of bisadducts of fullerenesF. Djojo, A. Hirsch, Chem. Eur. J. 4 (1998), 344 – 356Layer: ALUGRAM® ALOX N/UV254, 20 x 20 cm, Cat. No. 818 023; Eluent: toluene/ ethyl acetate (95:5, v/v)Detection: UV, 254 nm; Rf values:Bis[bis(4-phenyloxazolin)methan]fullerene 1: 0.14Bis[bis(4-phenyloxazolin)methan]fullerene 2: 0.26
N N
O O
Ph Ph
N
N
O
O
Ph
Ph
N N
OO
N
O
NO
Ph
Ph
Ph
Ph
1 2
4019
30
0.0 25.0 50.0 75.0 125.0
Stage Y (mm)
0.000
0.100
0.200
0.300
1
2
3
4
Separation of lipophilic dyesLayer: ALOX-25 UV254Sample volume: 1000 nlEluent: toluene/cyclohexane (2:1, v/v)Migration distance: 10.8 cm in 15 minDetection: TLC scanner, UV 254 nmPeaks:1. Indophenol2. Sudan red G3. Sudan blue II4. Butter yellow
4030
10
Designation Thickness of layer
Plate size [cm] Fluorescent indicator4 x 8 5 x 20 20 x 20
ALOX N 0.20 mm 802012 802013 –ALOX N/UV254 0.20 mm 802021 802022 802023 UV254
ALUGRAM® aluminium sheets 50 / pack 25 / pack
ALOX N 0.20 mm 818025 818013 –ALOX N/UV254 0.20 mm 818024 818023 UV254
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Cellulose · TLC ready-to-use layers
289
Unmodified cellulose layers
Cellulose is especially used for partition chromatographicseparations of polar substances such as amino acids andother carboxylic acids or carbohydrates. Compared to paperchromatography (PC) thin layer chromatography on celluloseoffers shorter migration times and more concentrated sub-stance spots resulting in a higher detection sensitivity.TLC ready-to-use layers CEL 300 are coated with native, fi-brous cellulose. TLC ready-to-use layers CEL 400 are coat-ed with microcrystalline cellulose AVICEL®. This type ofcellulose is prepared by hydrolysis of high purity cellulosewith hydrochloric acid. Depending on the starting celluloseand the following clean-up one obtains cellulose crystalliteswith a mean degree of polymerisation between 40 and 200.The microcrystalline structure of this cellulose can be con-
firmed by X-ray investigations. So far the following com-pounds could be successfully separated: carboxylic acids,lower alcohols, urea and purine derivatives. The separation characteristics of CEL 300 and CEL 400 aresomewhat different. For this reason we recommend that youtry both types for method development and then select themore suitable type from experience.The fluorescent indicator used for cellulose layers allows inmany cases viewing of substances in short-wave UV light of254 nm. The greenish fluorescence is quenched by sub-stances with a native absorption above about 230 nm; theseappear as dark spots. For detection of amino acids or pep-tides with ninhydrin cellulose ready-to-use layers without flu-orescent indicator are better suited than fluorescent layers.
Ordering information
Cellulose ion exchangers Cellulose ion exchange layers are suited for the separation ofsubstances with exchange-active groups. Consequently theyare used for the separation of amino acids, peptides, en-zymes, nucleic acid constituents (nucleotides, nucleosides)
etc. We supply TLC ready-to-use anion exchange layers ofDEAE cellulose (diethylaminoethyl cellulose, R-O-C2H4-N(C2H5)2) and PEI cellulose. The latter is not a chemicallymodified cellulose, but a complex of cellulose and poly-
Designation Thickness of layer
Plate size [cm] Fluorescent indicator4 x 8 5 x 20 10 x 20 20 x 20
Cellulose MN 300 native fibrous cellulose
Glass plates100 / pack 50 / pack 25 / pack
CEL 300-10 0.10 mm 808011 808012 808013 –CEL 300-10 UV254 0.10 mm 808021 808022 808023 UV254CEL 300-25 0.25 mm 808032 808033 –CEL 300-25 UV254 0.25 mm 808042 808043 UV254
20 / packCEL 300-50 0.50 mm 808053 –CEL 300-50 UV254 0.50 mm 808063 UV254
CEL 400-10 0.10 mm 808072 808073 –CEL 400-10 UV254 0.10 mm 808082 808083 UV254
POLYGRAM® polyester sheets50 / pack 25 / pack
CEL 400 0.10 mm 801112 801113 –CEL 400 UV254 0.10 mm 801122 801123 UV254
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Cellulose · TLC ready-to-use layers
290
ethyleneimine. PEI cellulose is a relatively strong anion ex-changer, which is mainly used for the analyses of nucleic ac-ids. PEI layers should be stored in a refrigerator at 4 °C.When stored at room temperature PEI cellulose tends toshow a more or less pronounced yellow colouration, whichdoes not interfere with the separation but can impede theidentification of separated substances. Predevelopment withdistilled water diminishes an eventual yellow colouration. Animportant application of POLYGRAM® CEL 300 PEI is theanalysis of mutagenic substances with a 32P postlabellingprocedure (see application).Mixed layers of cellulose DEAE and HR for separation of mono- and oligonucleotides in nucleic acid hydrolysatesThe Medical Research Council Laboratory of Molecular Biol-ogy in Cambridge (UK) has developed a special procedurefor the separation of radioactively labelled mono- and oligo-nucleotides in hydrolyzates of ribonucleic acid. It is a 2-di-mensional procedure, in which mononucleotides and oligonu-cleotides are separated up to n = 50. The separation processconsists of 2 stages, first a high voltage electrophoretic groupfractionation on acetate sheets in the 1st dimension and thena thin layer chromatographic separation in the 2nd dimensionafter blotting of the preseparated substances onto a mixedlayer of DEAE cellulose and HR cellulose in the ratio 2 : 15.As eluent concentrated urea solutions with addition of homo-mix solutions are used, which consist of ribonucleic acid hy-drolyzates and dialyzates. Mononucleotides move up to thefront, and depending on chain length the oligonucleotides ap-pear between the Rf values 1 and 0. The evaluation of chro-matograms is by autoradiography after treatment with red ink,which contains radioactive sulphur 35S.References1) G. G. Brownlee et al., European J. Biochem. 11 (1969) 3952) B. E. Griffin, FEBS Letters 15 (1971) 1653) F. Sanger et al., J. Mol. Biol. 13 (1965) 373 – 398.
Cellulose ion exchangers · ordering information
Characterisation of DNA adducts of a food mutagen by 32P postlabelling
W. Pfau et al., Carcinogenesis 17 (1996) 2727-27322-Amino-3-methyl-9H-pyrido[2,3-b]indole (MeAaC) is a mutagen-ic and carcinogenic heterocyclic amine, which can be formedduring frying or broiling of protein-containing food. In vitro as invivo it forms covalent DNA adducts. After chemical reduction animportant DNA adducts could be detected by 32P postlabelling.Layer: 20 x 20 cm, POLYGRAM® CEL 300 PEI, (Cat. No. 801053)
cut to 10 x 10 cm Sample application:
with a 10 x 7 cm wick of filter paper MN 440Eluent:
1st dimension sodium phosphate buffer (1 M, pH 6.0)2nd dimension (opposite to 1st dimension)
5.3 M lithium formate, 8.5 M urea, pH 3.53rd dimension
(perpendiculat to 2nd dimension from left to right) 1.2 M lithium chloride, 0.5 M Tris/HCl, 8.5 M urea, pH 8.0
4th dimension 1.7 M sodium phosphate (pH 6.0)wash and dry plate between individual developing steps
Detection: autoradiography at –80 °C with intensifying screens.
Autoradiography of the 32P postlabelling / ion exchange TLCanalysis of DNA from primary rat hepatocytes after treatmentwith MeAaC: A) butanol extraction, B) nuclease P1. I, II and IIIimportant adducts.
4022
60Designation Thick-
ness of layer
Plate size [cm] Fluores-cent in-dicator
5 x 20 20 x 20 40 x 2050 / pack 25 / pack 25 / pack
Cellulose MN 300 DEAE diethylaminoethyl-modified cellulose ion exchanger
Cellulose MN 300 DEAE / MN 300 HRmixed layers of cellulose ion exchanger MN 300 DEAE and high purity fibrous cellulose MN 300 HR
Glass platesCEL DEAE/HR-MIX-20 0.20 mm 810064 –POLYGRAM® polyester sheetsCEL 300 DEAE/HR-2/15 0.10 mm 801084 –
Cellulose MN 300 PEI polyethyleneimine-impregnated cellulose ion exchanger
POLYGRAM® polyester sheetsCEL 300 PEI 0.10 mm 801052 801053 801054 –CEL 300 PEI/UV254 0.10 mm 801062 801063 801064 UV254
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Cellulose / Polyamide · TLC ready-to-use layers
291
Acetylated cellulose
Acetylated cellulose (AC cellulose) is suited for reversedphase chromatography. It is prepared by esterification of cel-lulose with acetic acid. Up to three hydroxy groups per cellu-lose unit can be acetylated. The acetyl content can vary froma few percent to maximal 44.8%. This value corresponds tothe cellulose triacetate. With increasing acetyl content thehydrophobic character of the AC powder also increases. With
a different degree of acetylation of the cellulose thus a con-tinuous transition from a hydrophilic to a hydrophobic phaseis obtained. For selection of the eluent it should be noted thatthe different esters, i.e. mono-, di- and triacetate are solublein some organic solvents. We supply ready-to-use layers with10 and 20% AC cellulose (absolute contents), designatedAC-10 and AC-20.
Ordering information
Polyamide · TLC ready-to-use layers Our ready-to-use layers with polyamide are coated withpolyamide 6, i. e. perlon (= ε-aminopolycaprolactam). Theycan be supplied with or without an acid resistant UV indicatorwith a fluorescence at 254 nm. Due to the amide groups ofthe polymer matrix this phase can form hydrogen bonds withnumerous classes of compounds and thus allows separa-tions which are not possible with other adsorbents. Ready-to-use TLC sheets with polyamide are especially suited fornatural compounds, phenols, carboxylic acids and aromaticnitro compounds. For a detailed discussion of the chromato-graphic properties of polyamide please refer to the chapter“Adsorbents for TLC” on page 304.The polyamide phase has gained special importance for theanalysis of amino acids. The figure on the right shows a two-dimensional thin layer chromatogram of dansylated aminoacids on this layer.
Layer: POLYGRAM® Polyamide-6Eluent: 1st dimension: 1.5% (v/v) aqueous formic acid 2nd dimension: toluene / glacial acetic acid (10:1, v/v)Migration distance: 9 cm each in both dimensionsDetection: fluorescencePeaks:1.) DNS-leucine2.) DNS-phenylalanine3.) DNS-proline4.) DNS-valine5.) DNS-alanine6.) DNS-glycine
1st dimension
2nd d
imen
sio
n
start
4019
40
Designation Thickness of layer
Plate size [cm] Fluores-cent indi-
cator5 x 20 20 x 20
50 / pack 25 / pack
POLYAMIDE-6 = perlon = ε-aminopolycaprolactame
POLYGRAM® polyester sheetsPOLYAMIDE-6 0.10 mm 803012 803013 –POLYAMIDE-6 UV254 0.10 mm 803022 803023 UV254
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Special ready-to-use layers for TLC / HPTLC
292
CHIRALPLATE . the first TLC plate for control of optical purity
Gas chromatographic and high performance liquid chromato-graphic separations of enantiomers have been extensivelystudied. These methods require costly equipment and some-times sample derivatisation is necessary. Hence, develop-ment of a chiral TLC plate – called CHIRALPLATE – washighly desirable to achieve simple, rapid highly sensitive andeffective control of optical purity. CHIRALPLATE has beendeveloped several years ago in co-operation with DegussaAG, Hanau, Germany. Separation mechanismCHIRALPLATE is a TLC glass plate coated with a reversedphase silica gel, and impregnated with a chiral selector (a pro-line derivative, DP 31 43 726 and EP 0 143 147) and copper(II)ions. It allows multiple simultaneous separations, a great ad-vantage for routine applications and production control. Theseparation of optically active isomers is based on ligand ex-change: the chiral selector on the plate and the enantiomers tobe separated form diastereomeric mixed chelate complexeswith the transition metal ion (copper in the case of CHIRAL-PLATE). Complexes for the different antipodes have differentstabilities thus achieving chromatographic separation.
Chromatographic conditions for use of CHIRALPLATEOur CHIRALPLATE is a ready-to-use plate. No circumstan-tial dippings in different solvents or solutions are necessary.For amino acid derivatives most of the separations achievedso far have been run with a mixture of methanol – water –acetonitrile in the ratio 50:50:200 v/v/v (eluent A, developingtime about 30 minutes) or 50:50:30 v/v/v (eluent B, develop-ing time about 60 minutes). By changing the amount of ace-tonitrile in the developing solvent you can influence efficiencyand separation time. Lowering the acetonitrile concentrationrapidly increases separation times. U. A. Th. Brinkman etal.1) investigated the influence of the composition of differentbinary mixtures of acetonitrile and water on the separation ofdifferent amino acid racemates (see fig. below)
Though the above mentioned solvent mixtures are useful toseparate many substances, in special cases other eluentsmay be required 2). Thus leucine can be separated in a mix-ture of methanol – water (10:80 v/v, developing time about90 min); alanine and serine can be resolved with acetone –methanol – water (10:2:2 v/v/v, developing time ~ 50 min);N-carbamyl-tryptophan is separated with 1 mM cupric ace-tate solution containing 5% methanol (pH 5.8) 3) and enanti-omeric α-hydroxycarboxylic acids could be resolved usingdichloromethane – methanol (45: 5 v/v, developing timeabout 20 min) 2), 4).
Ordering information
Enantiomer separation of amino acids 2),6)
Quantitative determination (remission location curves) ofTLC-separated enantiomers of tert.-leucine: a) L-tert.-leu-cine, b) L-tert.-leucine + 0.1% D-tert.-leucine, c) L-tert.-leu-cine + 1 % D-tert.-leucine, d) external reference sampleLayer: CHIRALPLATE, eluent: methanol – water (10:80, v/v), detection: dip in 0.3% ninhydrin solutionquantification with scanner, 520 nm
a b c d
Dependence of the Rf values of the two antipodes of D,L-glutamine from the acetonitrile content of the eluent 1)
Rf
1.00
0.50
0.00
% CH3CN40 60 80 100
D
L
Glutamine
Designation Thickness of layer
Plate size [cm] Fluorescent indicator5 x 20 10 x 10 10 x 20 20 x 20
CHIRALPLATE RP-modified nano silica coated with Cu2+ ions and chiral reagent, for enantiomer separation
CHIRALPLATE 0.25 mm 811057 811059 811055 811058 UV254
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Special ready-to-use layers for TLC / HPTLC
293
For optimal separations and reproducible Rf values werecommend activation of plates prior to spotting (15 minat 100 °C) and use of chamber saturation for develop-ment. According to U. A. Th. Brinkman et al. 1), however, insome cases good separations can be achieved in 5 minuteswithout activation and without chamber saturation.Nyiredy et al. 5) described the application of CHIRALPLATEin forced-flow planar chromatography.Detection and quantitative determinationsDifferent detection methods are required for the differentcompounds separated: for proteinogenic and nonproteino-genic amino acids plates are dipped for 3 sec in a 0.3% nin-hydrin solution in acetone (or sprayed with ninhydrin sprayreagent), then dried for about 5 minutes at 110 °C. Red de-rivatives are formed on a white background. Vanadium pen-toxide is especially useful for post-chromatographic derivati-sation of α-hydroxycarboxylic acids. As shown by Günther 2),
6), quantitative evaluation of antipodes separated on CHI-RALPLATE is easily accomplished using a double beamscanner or a densitometer. In order to enhance specificityand sensitivity, post-chromatographic derivatisation with nin-hydrin or vanadium pentoxide is recommended. This methodallows determination of trace levels down to 0.1% of oneenantiomer in an excess of the other.Application of CHIRALPLATEApplications published so far include separations of
and others 7) – 14). Feldberg and Reppucci describe the TLCseparation of anomeric purine nucleosides on CHIRAL-PLATE 15). A review on the application of CHIRALPLATE hasbeen given by Günther 2). Procedures for the control of optical purity of L-dopa 16) andD-penicillamine 17) prove effectiveness of our CHIRALPLATEfor pharmaceutical applications. In addition to the separationof enantiomers CHIRALPLATE shows increased selectivityfor diastereomers as shown for D,L-alanyl-D-phenylalanineand L-alanyl-D,L-phenylalanine.Separations of other groups of optically active compoundsseem possible, if these compounds can be separated byligand exchange, i.e. if they can form chelate complexes withcopper(II) ions. The following tabulated summaries show some examples ofthe compounds separated so far. For applications see our in-teractive collection of chromatography applications on the in-ternet:
References1) Rapid separation of enantiomers by TLC on a chiral sta-
tionary phase. U. A. Th. Brinkman et al., J. Chromatogr. 330 (1985) 375 – 378
2) TLC enantiomeric resolution via ligand exchange. K. Günther, J. Chromatogr. 448 (1988) 11 – 30
3) Enantiomeric separation of N-carbamoyltryptophan by TLC on a chiral stationary phase. L. K. Gont and S. K. Neuendorf, J. Chromatogr. 391 (1987) 343 – 345
4) H. Jork and E. Kany, private communication 1987 (GDCh-Fortbildungskurs No. 301, Saarbrücken)
5) Applicability of forced flow planar chromatographic meth-ods for the separation of enantiomers on CHIRALPLATESz. Nyiredy et al., J. Chromatogr. 450 (1988) 241 – 252
6) Quantitative Auswertung von dc-getrennten Enanti-omeren. K. Günther, GIT Suppl. 3 (1987) 27 – 32
7) TLC enantiomeric separation via ligand exchange. K. Günther et al., Angew. Chem. 96 (1984) 514; Angew. Chem. Int. Ed. Engl. 23 (1984) 506
8) TLC enantiomeric resolution. K. Günther, J. Martens and M. Schickedanz, Naturwissensch. 72 (1985) 149 – 150
9) TLC separation of stereoisomeric dipeptides. K. Günther et al., Angew. Chem. 98 (1986) 284 – 285, Angew. Chem. Int. Ed. Engl. 25 (1986) 278 – 279
10)TLC enantiomeric resolution of α-alkyl amino acidsK. Günther et al., Z. Anal. Chem. 325 (1986) 298 – 299
11)Enantiomeric resolution of N-methyl-α-amino acids und α-alkyl-α-amino acids by ligand-exchange chromatogra-phy. H. Brückner, Chromatographia 24 (1987) 725
13)Resolution of 2-amino-5-thiomethyl pentanoic acid (ho-momethionine) with aminopeptidase from pseudomonas putida or chiral phosphoric acids. B. K. Vriesema et al., Tetrahedron Letters 26 (1986) 2045 – 2048
14)The importance of TLC as a rapid method for the control of optical purityR. Rausch, in "Recent advances of thin layer chromatog-raphy", F. A. A. Dallas, H. Read, R. J. Ruane and I. D. Wilson, Eds. Proceedings of the Chromatographic Soci-ety International Symposium on Thin Layer Chromatogra-phy 1987, Plenum Press, New York 1988, 151 – 161
15)Rapid separation of anomeric purine nucleosides by TLC chromatography on a chiral stationary phase. R. S. Feld-berg et al., J. Chromatogr. 410 (1987) 226 – 229
16)Resolution of optical isomers by TLC. Enantiomeric purity of L-dopa. K. Günther, J. Martens and M. Schickedanz, Z. Anal. Chem. 322 (1985) 513 – 514
17)Resolution of optical isomers by TLC. Enantiomeric purity of D-penicillamine. K. Günther et al., Arch. Pharm. (Wein-heim) 319 (1986) 461 – 465
18)Resolution of optical isomers by TLC: enantiomeric purity of methyldopa. K. Günther, J. Martens, M. Schickedanz, Arch. Pharm. (Weinheim) 319 (1986) 572
www.mn-net.com
Please ask for our catalogue ”Solutions for Chiral Chromatography" with numerous applications
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Special ready-to-use layers for TLC / HPTLC
294
Ready-to-use TLC plates SIL G-25 HR for separa-tion of aflatoxins For analytical detection of aflatoxins – the extremely toxicmetabolic products of mold – thin layer chromatography isused as a routine method. Detection is possible under UVlight. A test of numerous adsorbents and ready-to-use layersshowed, that our silica G-HR and the corresponding glassplates SIL G-25 HR give excellent results for the separationof aflatoxins. TLC separations with layers of silica G-HR arementioned in numerous publications. The layer of the glass plate SIL G-25 HR contains gypsum asbinder and a very small quantity of an organic highly poly-meric compound. The layer is considerably softer than for thestandard plate and therefore especially suited for separa-tions, where substance spots are to be scratched from theplate or for cases, where fast-absorbing layers are preferred.
TLC ready-to-use plates SIL G-25 TENSIDE for theseparation of detergents, alkanesulphonates, poly-glycols etc. and for assessment of fetal lung matu-rity The TLC separation of surfactants on layers of silica G – im-pregnated with ammonium sulphate – is recommended in anumber of publications. For either personnel or technical rea-sons many laboratories no longer have the possibility to pre-pare TLC plates with special impregnation. This is why wesupply a TLC glass plate coated with ammonium sulphateimpregnated silica G.For the assessment of fetal lung maturity it is essential to de-termine the ratio lecithin/sphingomyelin and detect the pres-ence of phosphatidylglycerol in amniotic fluid. Both determi-nations are possible after one TLC separation on SIL G-25TENSIDE.
TLC ready-to-use layers with kieselguhr
TLC ready-to-use layers with kieselguhr coating are not verysignificant. Kieselguhr is completely inactive and for this rea-son is mostly used for special separations after suitable im-
pregnation, e.g. impregnation with EDTA for separation oftetracycline broad-spectrum antibiotics (see DAB 8 and EABVol. II, p. 360).
For separation of M1 2-dimensional development: 1st dimensiondiethyl ether / methanol / water (940:45:15, v/v), chamber satura-tion; 2nd dimension chloroform / acetone (90:10, v/v)
G2G1
B2 B10.4
0.0
50 1004000
50
Investigation of amniotic fluid extracts for assessment of the neonatal respiratory syndrome
M.J. Whittle, A.I. Wilson, C.R. Whitfield, R.D. Paton, R.W. Logan,Br. J. Obstet. Gynaecol. 89 (1982) 727-732Exact prediction of the neonatal respiratory syndrome requiresdetermination of the lecithin/sphingomyelin (L/S) ratio as well asdetection of phosphatidylglycerol (PG) in amniotic fluid. CasesL/S ≥ 2 or < 2 and PG present or absent are of significance. Bothdeterminations are possibel in one TLC separation on SIL G-25TENSIDE.Layer: TLC glass plate SIL G-25 TENSIDE Laufmittel: 2-dimensional development
Migrationdistance: 2 x 10 cm in 30 minutes each, ascendingDetection: charring (10 min at 250 °C), then planimetric
determination of the L/S ratio, check whether PG present or absent400730
Designation Thickness of layer
Plate size 20 x 20 cm Fluorescent indicator25 / pack
SIL G-25 HR high purity silica 60 with gypsum, recommended for aflatoxin separationsSIL G-25 HR 0.25 mm 809033 –SIL G-25 HR/UV254 0.25 mm 809043 UV254
SIL G-25 Tenside silica G with ammonium sulphate for separation of surfactantsSIL G-25 Tenside 0.25 mm 810063 –
GUR N TLC ready-to-use layers with kieselguhr GUR N-25 0.25 mm 810074 –GUR N-25 UV254 0.25 mm 810073 UV254
MN www.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Special ready-to-use layers for TLC / HPTLC
295
Nano-SIL-PAH HPTLC ready-to-use layer for separation of polycyclic aromatic hydrocarbons
For TLC separation of polycyclic aromatic hydrocarbons(PAH) special TLC layers have been described 1) – 3), whichhave been impregnated or dipped with electron acceptors ofdifferent strengths. The PAHs act as electron donors and withthese electron acceptors form charge-tranfer complexes,which can be separated chromatographically. Funk et al. 4), 5)
developed a method, in which TLC ready-to-use plates aredipped with the electron acceptor caffeine and which sepa-rates the six PAHs according to the German drinking waterspecifications (TVO). This method of impregnation by dippingis also recommended in the German standard DIN 38407,part 7 “Determination of six polycyclic aromatic hydrocar-bons in drinking water and mineral water via HPTLC”. In or-der to save our customers the circumstantial dipping ofplates, we have developed the HPTLC ready-to-use plateNano-SIL-PAH. This plate can – without dipping – be directlyused for the method recommended in the German standardDIN 38407, part 7, because the layer already contains therequired electron acceptor. As adsorbent the plate is coatedwith our well-known nano-silica with 60 Å pore size and 2 –10 µm particle size. Due to the outstanding separation per-formance of Nano-SIL-PAH the six PAHs according to TVOcan be very well quantitated.References1) A. Berg, J. Lam, J. Chromatogr. 16 (1964) 157 – 1662) M. A. Slifkin, S. H. Liu, J. Chromatogr. 269 (1983) 103 – 1073) M. A. Slifkin, H. Singh, J. Chromatogr. 303 (1984) 190 – 1924) W. Funk et al., J. Planar Chromatogr. 2 (1992) 28 – 325) W. Funk et al., J. Planar Chromatogr. 2 (1992) 317 – 320
Ordering information · Glass plates
TLC ready-to-use layers with ion exchange resins
POLYGRAM® IONEX-25 precoated sheets are polyestersheets coated with a mixture of silica and a cation or anionexchange resin, respectively. Additionally these layers con-tain an inert organic binder. They are suited for separation ofamino acids, e.g. in protein and peptide hydrolysates, in
seeds and fodder, in biological fluids, for racemate separa-tion in peptide syntheses, for the separation of nucleic acidhydrolysates, aminosugars, aminocarboxylic acids, antibiot-ics, inorganic phosphates, cations and other compoundswith ionic groups.
Ordering information · POLYGRAM® polyester sheets
Separation of 6 PAHs according to German drinking water specifications (TVO)
Layer: Nano-SIL-PAHSample: 1 µl per 1 cm streak
(20 µg/ml per component)
Eluent: CH2Cl2, – 20 °CMigration distance: 8 cm in 20 minDetection: TLC scanner
Plate size [cm] 10 x 10 10 x 20 Fluorescent indicator Pack of 25 50
Nano-SIL PAH nano silica with special impregnation for PAH analysis
Nano-SIL-PAH 0.20 mm 811050 811051 –
Designation Thickness of layer
Plate size [cm] 20 x 20 Fluorescent indicatorPack of 25
IONEX TLC ready-to-use layers with mixed layers of ion exchange resins / silica
IONEX-25 SA-Na strongly acidic cation exchanger 0.20 mm 806013 –IONEX-25 SB-AC strongly basic anion exchanger 0.20 mm 806023 –
MNwww.mn-net.com
Ready-to-use layers for TLCReady-to-use layers for TLC
Special ready-to-use layers for TLC / HPTLC
296
Mixed layers · TLC ready-to-use plates TLC ready-to-use plates ALOX/CEL-AC-Mix-25 for sepa-ration of polycyclic aromatic hydrocarbons (PAHs)Polycyclic aromatic hydrocarbons (PAHs) are among themost frequent carcinogens in the environment. For this rea-son environmental agencies in most countries define maxi-mum allowable concentrations e.g. in drinking water, whichhave to be frequently controlled. A successful analytical pro-cedure is based on fluorescence measurement after TLCseparation on mixed layers of aluminium oxide G andacetylated cellulose. We supply corresponding glass plateswith mixed layers under the designation ALOX/CEL-AC-Mix-25. H. Hellmann [Z. Anal. Chem. 295 (1979) 24] notes that thefluorescence intensity of the individual compounds can varyconsiderably during separation as well as later on, which isimportant for the evaluation of a chromatogram.For separation of polycyclic aromatic hydrocarbons you canalso use layers of acetylated cellulose without addition of alu-minium oxide, our wettable TLC plate RP-18 W/UV254 or thespecially impregnated plate Nano-SIL-PAH.TLC ready-to-use plates GURSIL-Mix-25 UV254In thin layer chromatography, kieselguhr is not only used aspure adsorbent, but also as mixed layer with silica for theseparation of carbohydrates, antioxidants, steroids and pho-tographic developer substances. MACHEREY-NAGEL offersa TLC plate for this purpose under the name GURSIL-Mix-25UV254. These mixed layers show a reduced adsorption ca-pacity compared to plain silica layers and allow rapid separa-tions. Carbohydrates such as glucose, sorbitol and mannitolcan be separated on this layer with isopropanol/ethylacetate/water (83:11:6, v/v) as eluent. The eluent carbontetrachloride/glacial acetic acid (75:25, v/v) is suited for theseparation of photographic developer substances such aspyrocatechol, hydroquinone, pyrogallol, 1-phenyl-3-pyrazo-lidone and p-phenylene diamine.
TLC ready-to-use plates SILCEL-Mix-25 UV254 for sepa-ration of preservatives Layers of polyamide 11 UV254 were successfully used formany years especially for the separation of food preserva-tives [see J. Clement et al., Z. Anal. Chem. 248 (1969) 182].Unfortunately, polyamide 11 is no longer produced. For thisreason we have developed – based on a publication of J. A.W. Gosselé [J. Chromatogr. 63 (1971) 433] a TLC glass platewith a mixed layer of cellulose and silica, which is extremelywell suited for the separation of preservatives (benzoic acid,sorbic acid, salicylic acid, p-hydroxybenzoic acid and lowerp-hydroxybenzoates).Our TLC glass plate SILCEL-Mix-25 UV254 with the mixedlayer of silica and cellulose is also very well suited for sepa-ration of numerous other antimicrobial compounds.
Ordering information
Determination of polycyclic aromatic hydrocarbons (PAHs) according to German drinking water specifications
Investigation of potential interference with other PAHs H. Kunte, Fresenius Z. Anal. Chemie 301 (1980) 287-289Layer: TLC glass plate ALOX/CEL-AC-Mix-25Eluent: 1st dimension: n-hexane / benzene* (9 : 1)
2nd dimension: methanol / diethylether / water (4 : 4 : 1)Detection: fluorescence* Instead of benzene we recommend the less toxic toluene.
401040
Separation of preservativesJ.A.W. Gosselé, J. Chromatogr. 63 (1971) 433For separation of preservatives mixed layers of silica and cellu-lose are especially suited. This paper also describes several vis-ualisation reagents for the substances investigated.Layer: TLC glass plate SILCEL-Mix-25 UV254Eluent: petroleum ether(40/60) / carbon tetrachlo-
Migration distance: 16 cm ascending, 2-fold development, chamber saturation
Detection: UV 254 nm401420
Designation Thickness of layer
Plate size [cm] Fluores-cent in-dicator
10 x 20 20 x 2050 / pack 25 / pack
Mixed layersGlass plates
Aluminium oxide G / acetylated cellulose ALOX/CEL-AC-Mix-25 0.25 mm 810054 810053 –
Cellulose / silica
SILCEL-Mix-25 UV254 0.25 mm 810043 UV254
Kieselguhr / silica
GURSIL-Mix-25 UV254 0.25 mm 810076 UV254
MN www.mn-net.com
Paper chromatographyPaper chromatography
Chromatography papers
297
Paper chromatography (PC) is the oldest chromatographictechnique. As with the other chromatographic proceduresseparation is achieved by partition of the mixture to be sepa-rated between two immiscible phases. The stationary phase,for PC the chromatography paper, is intensely penetrated bythe mobile phase through capillary action.In normal paper chromatography the cellulose of the paper,which is loaded with water, forms the stationary phase, asmobile phase organic solvents or solvent mixtures with limi-ted miscibility with water are used. Contrary, for PC with reversed phases (RP chromatography)the paper is impregnated with hydrophobic solvents (e.g. for-mamide, dimethylformamide, paraffin oil, undecane, siliconeoil), as mobile phase (eluent) hydrophilic solvents such as al-cohols are used.Strictly speaking the chromatography paper is only the sup-port for the liquid stationary phase, however, the propertiesof the paper have a considerable influence on the quality of aseparation. For a paper chromatographic analysis about 1 – 2 µl of the1 – 2% solution to be investigated is applied about 1.5 to2 cm from the edge of a strip of chromatography paper withthe aid of a micropipette and allowed to dry. Then the strip ofpaper is placed into a developing chamber (e.g. glass trou-gh) charged with a suitable solvent mixture, such that theeluent can ascend in the paper by capillary action, but thesubstance spots are above the liquid level. The eluent willpass the starting points and transport the substances throu-gh the stationary phase, in this case the paper. Due to thedifferent retention of substances on the paper surface sepa-ration of the mixture will be achieved.When the eluent has almost reached the other end of the pa-per, remove the strip from the developing chamber, mark thesolvent front with a lead pencil and dry the paper. As in thinlayer chromatography for PC substances have to be visua-lised after separation.Ascending, descending and circular techniques are also pos-sible in paper chromatography.
Thus high quality filter paper is the medium for the separa-tion process in PC. Papers used for PC are generally calledchromatography papers, however, they are basically specialhigh-quality filter papers. As raw material for chromatographypapers mostly linters are used, i.e. short cotton fibres, whichare no longer suited for textile application, but they are espe-cially suited for the manufacture of filter papers. As compa-red to pulp linters possess an intrinsic high purity and a veryhigh content of α-cellulose. Last but not least linters are ad-vantageous, because they have relatively long fibres andthus allow a defined grinding. This is an important prerequisi-te for the manufacture of homogeneous and flawless papers.Chromatography papers and cartons have to be treated ca-refully. For example they should never be touched with fin-gers, because in addition to water the human skin transpira-tes salts, fats, amino acids and other substances, which caninterfere with the separation.Chromatography papers should not be bent sharply, becau-se this will decrease the capillary action. For this reasonsheets should preferably be stored flat, in any case never rol-led to narrow.Due to the manufacturing process in the paper machine thefibres will assume a preferred direction. For this reason everychromatography paper will show slightly different absorptiveproperties in different directions: in the direction of the fibresthe absorption is generally higher than vertical to it. This iswhy for chromatography one should always work in the direc-tion of higher absorption. For our sheets 58 x 60 cm this isthe longer edge.If for smaller cuts of a sheet the preferred direction can nolonger be determined from the ratio of the edges, simply ap-ply a drop of water to the paper: the spot will assume an el-liptical shape, the longer axis showing the preferred direc-tion.The most important parameters for chromatography papersare weight, thickness and migration distance. For chromato-graphy papers the migration distance is usually given inmm / 30 minutes, though normally in the paper industry themigration distance according to Klemm is used, i.e. the hei-ght of a strip of 15 mm width, which is wetted in 10 minuteswhen dipped in dist. water of 20 °C.
Ordering information
*) This paper is extracted with organic solvents
For further papers, filters and membranes, feel free to ask for our catalogue ”Filtration“
Code Weight [g/m2]
Thickness [mm]
Description Flow rate Size [cm]
Pack of Cat. No.
MN 214 140 0.28 smooth 90 – 100 mm/30 min 58 x 60 100 sheets 817001MN 218 180 0.36 smooth 90 – 100 mm/30 min 58 x 60 100 sheets 817002MN 260 90 0.20 smooth 120 – 130 mm/30 min 58 x 60 100 sheets 817003MN 261 90 0.18 smooth 90 – 100 mm/30 min 58 x 60 100 sheets 817004MN 827 270 0.70 soft carton 130 – 140 mm/10 min 58 x 60 100 sheets 817005MN 866 650 1.70 soft carton 100 – 120 mm/10 min 38 x 38 100 sheets 817006MN 866 650 1.70 soft carton 100 – 120 mm/10 min 80 x 80 100 sheets 817007MN 214 ff 140 0.28 MN 214 defatted * 90 – 100 mm/30 min 56 x 58 100 sheets 817008
