V olume 8 June, 1970 JOURNAL OF THE ASSOCIATION OF PUBLIC ANALYSTS Annual Report of Council for 1969 Presented qt the Annual General Meeting of the Association of Public Analysts held in London on 15th May,197O, by the Honorary Secrctary, Mr. F. A. Lyne. Although, as scientists, we may argue that logic decrees that 3lst December, 1969, does not mark the end ofa decade but that we must wait for another full year, the writing of "1970" seems to usher in a new era and it is tempting to raise one's eyes beyond the immediate events of the past twelve months to survey the road which we have travelled and to attempt to peer into the future. In a sense we may stand on a watershed in time. The century which has passed since Public Analysts came into being was a period of evolution, slow at first but with ever-increasing momentum in the last two decades, which has transformed the service from the dingy back room to the highly sophisticated modern laboratory able to keep pace with technological progress and to guard the public against new environmental hazards. Wlere major changes are contemplated involving the redeployment of tens of thousands of Local Government employees and the re-allocation of resources involving an annual expenditure of millions of pounds, the future of such a relatively minor function may seem to be of secondary importance, but we submit that the protection of the health and pockets of the population is as important as the other services provided by the authorities. In an article published in the National press, written by a well known Member of Parliament, the argument was put forward that the United States system ofthe Food and Drug authority, with its central organisation staffed by qualified scientists, doctors and administrators was more powerful and efficient than our own system administered as it is, on a more local basis. The argu- ment is not entirely one-sided. A central system can become ponderous, inflexible and expensive, but this Association is not committed to any par- ticular system. The criterion must be "what is best administered is best". Enoironmental Hazards Public opinion, particularly in the United States and now in Europe has been focused upon the problems associated with the impact of technology on our environment and the urgent need to arrest the erosion of our amenities before it is too late. The Duke of Edinburgh has ca11ed for action, and 1970 should be a signiflcant date in this campaign. There is talk of an "Environ- mental Year" to concentrate attention on the subject.
Transcript
V olume 8 June, 1970
JOURNAL
OF THE
ASSOCIATION OF PUBLIC ANALYSTS
Annual Report of Council for 1969
Presented qt the Annual General Meeting of the Association of PublicAnalysts held in London on 15th May,197O, by the Honorary Secrctary,Mr. F. A. Lyne.
Although, as scientists, we may argue that logic decrees that 3lst December,1969, does not mark the end ofa decade but that we must wait for another fullyear, the writing of "1970" seems to usher in a new era and it is tempting toraise one's eyes beyond the immediate events of the past twelve months tosurvey the road which we have travelled and to attempt to peer into the future.In a sense we may stand on a watershed in time. The century which haspassed since Public Analysts came into being was a period of evolution, slowat first but with ever-increasing momentum in the last two decades, which hastransformed the service from the dingy back room to the highly sophisticatedmodern laboratory able to keep pace with technological progress and to guardthe public against new environmental hazards.
Wlere major changes are contemplated involving the redeployment oftens of thousands of Local Government employees and the re-allocation ofresources involving an annual expenditure of millions of pounds, the future ofsuch a relatively minor function may seem to be of secondary importance, butwe submit that the protection of the health and pockets of the population isas important as the other services provided by the authorities.
In an article published in the National press, written by a well knownMember of Parliament, the argument was put forward that the United Statessystem ofthe Food and Drug authority, with its central organisation staffed byqualified scientists, doctors and administrators was more powerful and efficientthan our own system administered as it is, on a more local basis. The argu-ment is not entirely one-sided. A central system can become ponderous,inflexible and expensive, but this Association is not committed to any par-ticular system. The criterion must be "what is best administered is best".
Enoironmental HazardsPublic opinion, particularly in the United States and now in Europe has
been focused upon the problems associated with the impact of technology onour environment and the urgent need to arrest the erosion of our amenitiesbefore it is too late. The Duke of Edinburgh has ca11ed for action, and 1970
should be a signiflcant date in this campaign. There is talk of an "Environ-mental Year" to concentrate attention on the subject.
lo ANNUAL REpoRr oF rHE couNc[, 1969 [J.A.P.A., Vol. 8
Public Analysts are involved in several aspects of the problem particularlythe pollution of the atmosphere, the pollution of waterways and the pollutionor contamination of growing crops either accidentally or by chemical sprays.
Since the time of the industrial revolution the rivers in industrial areas havebeen regarded as cheap and convenient means of disposal for industrial wastesas well as the effiuents from sewage disposal plants.
Indiscriminate discharges have converted many of the rivers of NorthernEngland and the lower reaches of the Thames into biological deserts. Theseas into which they flow are in danger of falling into the same state unlessrapid and firm action is taken. Analysis forms one ofthe essential links in thechain of remedial measures, as the data so obtained forms the basis ofappraise-ment of the degree and nature of pollution and its probable source.
Atmospheric pollution is another environmental hazard and analysis iseven more important in this context as the degree cannot be assessed by visualobservation of the direct effect on vegetable or animal life. The pollution ofthe atmosphere of our cities by the ever increasing volume of exhausts frommotor vehicles is an aspect which has only been examined sporadically and notin depth, This is a study which could well be undertaken on a far greaterscale by Public Analyst's laboratories, disposed as they are throughout thecountry and normally located in the large cities.
Impending legislation, relating to the health of industrial workers arisingout of their environment or the materials which they handle, will require alarge amount of analytical control.
The subject of pesticide residues in crops has been mentioned in earlierAnnual Reports of this Association and the nationwide survey of the level ofpesticide residues ingested by the population should serve as a model forfuture surveys of a similar kind. The results of the first year's work have beenpublished and the results of the second year's investigation are expected to bepublished during 1970.
During 1969 the organo-chlorine pesticides came to be regarded withgrowing disquiet, leading to the ban on D.D.T. for use in the home, garden orin vapourisers. The use of Aldrin, Dieldrin and D.D.T. should be restrictedaccording to the recommendations ol the Advisory Committee on Pesticidesand other Toxic Chemicals. The problem is not a static one, new pesticidesare evolved and placed on the market, established ones fall into disuse or atleast into eclipse and the pattem of contamination changes. Although theinitial surveys show that the level o{ contamination in this country is signifi-cantly lower than in the United States, this is no argument for relaxing thevigil. Climatic variations may favour the proliferation of certain pests result-ing in heavier usage of pesticides or changes in agricultural practice may havethe same effect. It has been suggested that a third year's survey is unnecessaryin the light of the results of the work so far done, but such complacency isunjustified. The cost of vigilance is minute compared with the issues at stake.
These are some ofthe ways in which Public Analysts are contributing theirquota of effort to aid the fight for good environmental conditions.
/t
June, 19701
tr'oods
ANNUAI REPORT OF THE COUNCIL. 1969
Public Analysts were brought into being to ensure that lood was notadulterated. In the first half of the last century, gross, fraudulent and oftendangerous adulteration of food was rife. Over the last hundred years thissocial evil has almost entirely disappeared, but the need for Public Analystshas not lessened but rather increased. Their main concern nowadays is tomaintain reasonable standards of composition, to prevent false and misleadingclaims being foisted on the public and to guard against contamination arisingout of manufacturing or agricultural practices.
During 1969 there were few changes in legislation affecting the compositionof food. The one which attracted the most public attention was the ban oncyclamates as artificial sweeteners which was imposed at the end of the year.This was a precautionary measure following certain unconlirmed work whichalleged to show that consumption of massive amounts could give rise to irre-versable and progressive effects in the body. Further long term work is beingdone in this country to prove or disprove the validity of these flndings, but evenif they are found to be invalid, it is doubtful if cyclamates can be reinstated-"give a dog a bad name. . .". The fundamental problem is that of attemptingto prove a negative-that a given food additive cannot be harmful. By givingmassive doses of salt, evidence could be deduced that it could be harmful andshould be banned, although it has been in use for thousands of years and is infact an essential article of diet. A cynic might be tempted to speculate on theprobable fate of any other suggested artificial sweeteners or even on saccharinwhich has been in use for more than half a century.
This is not, however, a plea for more liberal use of food additives. As ageneral principle, Public Analysts are against a proliferation of permitted foodadditives and would like to see them restricted to a minimum. We thereforewelcome the review by the Food Additives and Contaminants Committee of theuse of butylated hydroxytoluene as an antioxidant and the uses of the anti-biotics nisin, nystatin and tetracyclines which are permitted preservatives incertain foods. The use of antibiotics in this manner may encourage thedevelopment ofresistant strains ofbacteria which may not be capable ofcontrolby antibiotics should occasion arise. Our experience is that, although legal,the use of these substances has been very limited.
The labelling of food poses many difficult problems, but the criterion mustalways be whether a given label is likely to mislead an intending purchaser.Proposals to amend the existing labelling ofFood Order (1953) have been besetby repeated postponements and further amendments which always seem tolessen the force of the proposed Regulations. An example of this is the use ofthe term "home made". Original proposals would not have permitted the application of this term to mass-produced foods, but in the latest Regulations thisban has been discarded. How "ready" is a "ready meal" ? Initially a"readymeal" only required heating up, but it is now being extended to include pre-paration which could take perhaps 30 minutes. We deplore the gradualdebasement of these terms and feel that Labelling Regulations should be
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28 ANNUAL REpoRr or rHE couNcrI,, 1969 p.A.p.A., Vol. 8
formed to prevent it. Many other well-intentioned proposals such as arequirement to print certain essential information in a certain size of type on acontrasting background are eventually watered down to vague terms as ,.con-spicuous" or "clear and conspicuous", which axe open to a range ofinterpretations. This use of undefined general terms always leads to virtuallyunsurmountable difficulties, because Local Authorities are very reluctant totake legal proceedings the outcome of which depends on the interpretation ofthe meaning of words in legal documents.
DrugsEadier Annual Reports have recounted the efforts of this Association to
establish the principle that the control of drugs should be in the hands of inde-pendent Authorities as in the case of the Food and Drugs Act. The effect ofthe Medicines Act will be to temove them from the Food and Drugs Act, sothat the latter will become a Food Act. This narrowing of the scope is indirect contrast to the U.S. legislation where the main Act is extended to includecosmetics. The Medicines Act is not yet operative as a great deal of pre-liminary work is necessary before the "appointed day" can be fixed. It isgratifying to note that this Association has been consulted regarding thecomposition of the main Commission and no doubt will be regarding theExpert Committees.
" Bteathalizet Tests"Public Analysts are frequently called upon to make independent tests on
specimens of blood taken under the Road Safety Act. Criticisms of the pro-cedure have been voiced in our Annual Reports, particularly the report for1967. Many legal decisions have created loopholes in the Act although morerecent decisions in the House of Lords have had the effect of plugging some ofthese.
There has been some improvement in the procedure in that a higher pro-portion of samples are received in properly sealed envelopes, often beafing theadvice that, if the accused wishes it to be analysed, it should be kept in a coolplace and submitted for analysis within 5 days. Howevo a sealed envelopecan readily be unsealed and resealed and the capsule can be opened and re-closed without any apparent sign of tampering.
Not only is the capsule far from "temper proof" but owing to the methodand material of construction, it permits evaporation. Alcohol being morevolatile than blood evaporates more readily and analysis after a lapse of timeresults in a lower flgure. This lower figure is of little use to the defence as itcan be swept aside by saying that it was "due to evaporation". Many defend-ants are so convinced of their innocence that they do not have recourse to anindependent analyst until a Summons is received several weeks after the event,The Road Safety Act requires that the specimen shall be placed in a "suitablecontainer". Is a container which cannot be sealed and which permits evapora-tion "suitable" ? An adverse ruling on this point hy the High Court could wreck
June, 19701 ANNUAL REpoRT or rne couNctr-, 1969
this system. No great ingenuity would be required to devise a suitable con-tainer which would be free from the serious defects of the present one.
The Royal Institute of Chemistry in conjunction with this Association andin consultation with the Home Office has produced a more comprehensivebrochure giving a list of laboratories willing to analyse the defendant's sample.This should be in the hands ofall Police Forces who should be in a position toadvise defendants accordingly.
?oysThe Toys (Safety) Regulations, 1967, designed to prevent the use of toxic
paints on toys or the use of highly inflammable plastics (celluloid) except forcertain specified applications (table tennis balls), have been the subject ofdiscussion beiween this Association and the Government Laboratory. Twoyears of experience have revealed difficulties and imperfections. Thin printedfilms contain perhaps only one tenth the amount of pigment per unit surfacearea when compared with brush-painted toys, but are subject to the samelimits for metal content.
Would it not be more logical to express the limits on an area, rather thanon a weight of film? Unfortunately the difficulty of accurate measurement ofsurface area of small irregular toys makes the logical method impracticable.The selection of toxic metals specified in the Regulations includes some whichare of low toxicity but excludes some of high toxicity ; amendments should bemade.
From the point ofview of enforcement, difficulties arise because ofvariationin composition not only from toy to toy but also even over the surface of thesame toy. Unlike Foods or Drugs, toys cannot be divided into three identicalparts.
Fertilizers and Feeding StufisAfter a period of relative stagnation following the 1926 Fertilisers and
Feeding Stuffs Act, the last few years have seen vast changes in the requirementof the Act as laid down in Regulations made under the Act and the presentAgricultural Bill before the House will eventually replace the Act. ln additionto major constituents of the product, minor components such as trace elements,drugs (including coccidiostats, anti-blackhead drugs, hormones, etc.) andother additives must be declared and require checking. This has placed anenormous extra burden on the shoulders of Public Analysts acting in theircapacity as Official Agricultural Analysts, but at the same time makes the Actmore effective and meaningful.
The new Agriculture Bil1, if it goes through in its present form, promises tobe a more effective instrument than the present Fertilisers and Feeding StuffsAct. This Association has made representations designed to efect furtherimprovements.
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30 ANNUAL REpoRr oF rHE couNcr, 1969 [J,A.p.A., Vol. 8
Tlad.e Descfiptions ActThis Act, which came into force at the end of 1968, makes it an offence to
supply with any goods offered for sale a statement, whether written orverbal, that in any way misdescribes the goods or is inaccurate as regards theirquality, fitness for purpose, or in almost all other particulars. The responsi-bility of enforcing the Act is laid on Local Authorities, and this has thrown aheavy burden on their Officers. In particular, it has meant that public Analystsare receiving a wide variety of products for analysis, including petrol andparafrn, paints, fabrics, cosmetics and household cleaning materials. Someof these problems cannot be soived by chemical analysis; but public Analystsare meeting the challenge well and are exercising much ingenuity in devisingmethods of analysis and investigation that will answer the necessary questions.This increase in their duties, however, is straining the resources of their labora-tories, and if the work under this Act continues to grow at the present rate, anincrease in staff will be inevitable.
During 1969 the views of this Association were sought by various Govern-ment Departments, in particular the Ministry of Agriculture, Fisheries andFood, the Ministry of Health, the Home Office, etc., on a variety of topicsarising mainly out of proposed legislation or amendments to existing legislation.
We also maintained close contact with the Local Authorities Associationsand with kindred professional and scientific bodies. Our members serve onmany committees outside the Association, such as those ofthe British StandardsInstitution and the Codex Alimentarius, to name but two.
The Journal of the Association of Public Analysts has a world-wide circu-lation although the numbers are relatively small. In this respect it reflects theAssociation's position as a small specialist Association, wide-ranging in itsinterests and probably exercising an influence out of proportion to its numericalsrze.
We like to think that the spirit of service to the community which inspiredthe small handful of dedicated men who founded the then Society of publicAnalysts nearly 100 years ago, is still alive in us today, for on the efforts of sofew so much depends.
June, 19701 AN INVESTIGATION INTO PARAF'FIN QUALITY
An Investigation into Paraffin Quality
67 R. Fuocr aNo P. V. NrcHoLAs
(City ancl County of Bristol, Scientific Adviser's Departnent, Bristol)
The quality olparaflln used in wick-fed, unflued space heaters is discussed.Analytjcal results are given for a variety of fuels and sonle techniques usedin quality assessment and in the detection of adulteration are reviewed.
The fuel obtained by refining the kerosene distillation fraction ol crudepetroleum oil is generally termed paraffin. Most producers market a paraffindescribed as premium quality suitable for unflued, wick-fed, domestic spaceheaters. A British Standard defining paraffin for use in such appliances appearsto be urgently needed, and it is understood that one will be available laterthis year.
It is the Authors' contention that premium paraffin produced rvith unffuedappliances in mind shor-rld conform to higher standards of quality than regulargrade paraffin or burning oil, which is more suitable for use in flued appliancessuch as domestic central heating boilers. Important criteria relating toquality are the smoke and flash points, sulphur and aromatic contents and thechar valuel. With regard to appliance efficiency, the smoke point will affectthe quantity of smoke and soot produced. and the char value the life of thewick. Too low a smoke point may make it necessary to work below the maxi-mnm flame height possible fi'om the appliance and consequently reduce thecalori{ic output.
A Ministry of Defence Specification' sets out test limits for a grade ofparaffin (designated Grade A) preferred for wick-fed appliances and the largemajority of reputable producers ensure that their premium product conformsto the values given in this specification. Table I shows specified propertiesand typical limits adopted by many premium paralfin producers.
3l
TABLE ITYPICAL LIMITS ADOPTED BY MANY PREMIUM PARAFFIN PRODUCERS
Value adopted.. Mininrum of 35 m. . Maximum of 10 mg/kg. . Minimum ol 115'F. . Maximum of 0.06 per cent. by weight. . Level of 6-8 per cent. by weight. . Maximum of 0.820
.. Minimum of 15 per cent. by volume
. . Maximunr o1300'C
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32 R. -FUDGE AND P. V. NICHOLAS [.A.P.A., Vol. 8
GIVEN IN B.S. 33OO
Vahe quoted25 to 30 mmt0 ro 20 mg/kgAbove 100 F0.10 to 0.15 per cent. by weight
The B.S. 3300 Specification for unflued paraffin space heaters3 gives figuresfor a "test" paraffin shown in Table II.
TABLE IIVALUES OF QUALITY CRITERIA FOR A TEST PARAFFTN
PropertySmoke poinlChar value .. ..Flash point..Sulplrur conteni ..
The Specification states that "the test parallin has been prepared solely inorder to reveal various characteristics of the appliance under test". The testparaffin should not be used in testing the appliance for luel consumption, heatoutput or odour. ln these instances the fuel recommended by the appliancemanufactr-rrer is used.
It is the Authors' opinion that at least one large company appears to usethis type ol specification lor its "premium" paraffin, although thc figures are thosegenerally accepted for a regular grade paraffin for flued appliances, and tl.reterm "premiun" should not be used to describe a luel ofthis quality. In certaincircumstances the use ofparaffin ofthis nature in unflued heaters may constitutea health hazard ar.rd the sale of such palaffin as premium fuel is considereddetrimental to the consumer. The consumer is obviously lurther prejudicedif a branded prcmium paraffin is mixed with "other paraffin", particularly ilthe "other paraffin" is of inferior qLrality and adversely affects the performanceof the fuel. The Trade Descriptions Act, 1968, appears to be contravcned evenif the "other paraffin" is of prcmium grade and this arises if an economicalsource of such paramn is available.
In reviewing the nature of the "other paramn" it is usefui to consider otherproducts obtained from crude petroleum oil (Table Ill).
Two separate gr4des can be obtained from the kerosene fraction (approxi-mate boiling range 150-260' C). With comparatively little further refining itcan be sold as "regular" grade for use in flued appliances (B.S. 2869: Class C)a,or as aviation fuel. With more severe refining, to reduce the aromatic content,
June, 19701 AN INVMTIGATION INTO PARAFFIN QUALITY 33
a "premium" grade of high smoke point is produced by several major oilcompanies, for use in unflued appliances.
The most heavily taxed member of the Gas Oil and Kerosene groups isthe Diesel Oil used as a road vehicle fuel and consequently the other fuelsir, this group are requircd by the Customs and Excise Authorities to containchemical markers to enable their detection in admixtures with road vehicle fuel.
The marking of kerosene is required under The Hydrocarbon Oil Duties(Rebates and Reliefs) (Amendment No. 2) Regulations, I9675. The prescribedmarkers and proportions are:
"not less than one and three quarter pounds of Quinizarin (1,4-di-hydroxyanthraquinone) and not less than six pounds of Furfural(furfuraldehyde) to every one hundred thousand Imperial Gallons ofkerosene."
Aviation luel and special kerosenes that are relatively expcnsive, togetherwith tractor vapourising oil, are not required to contain markers. The markingis fulther waived in tlte case of dycd parallns, provided that the producersreveal to the Customs and Excise Authoritics the identity and propcrties ofthe particular dye incorporated in their paralins. Horvever, parallin fordomestic use, premium or regular grade, should contain the markers furfuraland quinizarin unless excmption has been grantcd by the Customs and ExciscAuthorities.
It is ll.reoretically possible for any of the members of the kerosene and gasoil fractions to be used to adulterate premium paraffin. The addition of thegas oils to any great extent is prohibited by such factors as its higher distillaiionend point and char value, which would cause a marked diffcrcnce in thebehaviour of the fuel. Regular grade paraffin is more sr:itable as an adulterantof premium fluel, and since it costs less its addition is economically viable.The addition of rcguiar grade paraffin to a dyed premium paraffin, which isexempt from the addition ol the chemical markers. should introduce thcmarkers into the sample.
Information concerning all facets of possible contraventions of the TradeDcscriptions Act is obtained if a measure of the aromatic content is madc andconsidered in conjunction with thc tests for the presence of markers andauthentic dye ofthe producer. The possible contraventions are inferior quality,adulteration with an inferior paraffin, or complete srjbstitution in an attemptto imitate a well known coloured brand.
Aladdin Pink paraffin produced by Shell-Mex & B.P. Ltd. is unusual inthat its registered tradc names are also Pink and Pink Aladdin. Consequentlyany paraffin sold as "Pink" should be entirely Aladdin Pink which is annnmarked premium fuel, dyed pink.
Apart from delibcrate adLllteration with other oils, the nature of the paraffinrvhich may be available to the consuner is shown diagramrnatically in Figure lUnclassified paralln in the diagram relers to unmarked and undyed paraffinof varl,ing quality, or special kerosenes, tractor vapourising oil, etc.
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34 R. FUDGE AND P. V. NICHOLAS [J.A.P.A., Vol. 8
ParafnnI
C,assified(Special interest under llre
Trade Descriptions Act, 1968)I
I
I
Unclassified(see text)
rremium icrade A)I
I
Regular (Grade B)
G",,l.,i,,.I
AdulteratedI
By subltitution
I
Substituted with Substituted withunclassified regular gradc
Fig.. l. Theoretical composition of paramn mixtures.
ExperitnentqlSamples of paraffin, described as either Aladdin Pink or Pink Paramn
were examined, together with samples marketed by other producers. Thesamples were taken under the Trade Descriptions Act, 1968.
Appan.atus1. Inlra Red Spectrophotometer.
2. Liquid cell, semi-permanent with 0.5 mm teflorr spacer and sodiumchloride windows.
3. Spectrophotometer with l-cm glass cells.
4. Lovibond Tintometer with 4 cm glass cells.
5. Smoke Point Lamp and Specified Wick.6. Flash Point Apparatus-Abel Petroleum Testing Apparatus.
Reagents1. Sodium hydroxide soltrtion: A 5 per cent. solution in distilled water.2. Hydrochloric ocid solution: A solution ol concentrated hydrochloric
acid and distilled water (l : l).3. Cyclohexane: Spectroscopically pure.
4. Aniline acetote reagent: Add 100-ml of aniline, A.R., to 900 ml ofglacial acetic acid. Store in a dark bottle.
Test Proceduresl. oerrnuruarroN oF eurNrzARtN coNTENT
Extract a 50-ml quantity of the paraffin with three portions of a mixtureof 5 ml of sodium hydroxide solution and 5 ml of butanol. Run the aqueousIayers into a separating funnel containing 6 ml of hydrochloric acid solution
L
BY addition
Plus regular Pluslrade unclassified
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June, 1970] AN rNvEsrrcArroN rNro eARAFFTN euAI-rry 35
and extfact the acid mixture with exactly l0 ml of cyclohexane. Plot theabsorption spectrum of the orange cyclohexane extract from 420 lo 540 mp.Absorption peaks characteristic of quinizaril are 463, 476, 487, 508 and521 mp. Determine the quinizarin quantitatively by comparing the intensityof absorption at 521 mpL of the extract with standard solutions of the markerin cyclohexane6,'.
As a qualitative test, the formation of a violet colour in the initial aqueouslayer indicates quinizarin, but the presence ol the characteristic absorptionpeaks should be established.
2. euALtrATIvE TEsr FoR FURFURAL
Shake 15 ml of the paraffin with 1 ml of aniline acetate reagent. Theformation of a red lower layer indicates the presence of furfurals. To over-come any interference due to the parafhn colour, distil a suitable quantity ofthe fuel to 220'C and carry out the test on the distillate-
3. EsrrMATroN oF col-ouREstimate the colour of the paraffin using a Lovibond Tintometer and
express the result in the relevant units.
4. ASSESSN{ENT oF THE ARoN{ATrc CoNTENT
Draw some ofthe sample into a hypodermic syringe, preferably one with aLuer Lock fitting, and transfer it to the liquid ce1l. Scan the Infra ReC spectrumfrom 650 to 2000 cm 1, adjusting to 100 per cent. transmittance at 2000 cm-1.Examine the spectrum with particular reference to the intensity of absorptionat 805 and 1605 cm 1. Wash the cell through with 50 to 100 times its volumeof chloroform and remove the last traces of solvent with an air or vacuum line.
5. sMoKE PorNT
Carry out the Smoke Point determination in accordance with the festMethod I.P. 57'g.
6. r'tasn poINt
Obtain a value for the Flash Point in accordance with Test Method LP. 170e.
7. sPECrFrc cRAvrrYDetermine the Specific Gravity in the usual manner.
Resurts ond DiscussionMarkers were lound in fourteen of the twentyone Pink Paraffins examined,
indicating the possibility of the addition of "other paraffin", and the tests forthe authentic Aladdin Pink dyero suggested the presence of some AladdinParaffin in the samples. The results compare lavourably with the Consumers'
36 R. FUDGE AND P. V. NICHOLAS [J.A.P.A., Vol. 8
TABLE IVCHARACTERISTICS OF VARIOUS COMMERCIAL PARAFFINS
Esso Blue Paralfinsll f.,o BIue \egative \egarive 0 62l t..o BIue 0 824 Esso Blue 0.E25 Esso Blue 0.626 Esso Blue 0.527 Esso Blue 0.72E Esso Blue 0.629 Esso Blue 0.730 Esso Blue 0.731 Esso tslue 0.j3l Esso BIue 0.833 Esso Blue 0.63,1 Esso Blue O./35 Esso Blue 0.736 Esso BIue 0.8
Association findingsll, although the percentage of .,adulterated,, samples isgreater, Markers were not found in the fifteen Esso Blue samples, oi thoseof the other producers.
3.14.03.0
2.8
June, 19701 AN INVESTTGATION INTO PARAFFIN QUALITY
7a
Premium grade paramn
t250
Fie. 2a
Wavelengrh,rm
Wavenumber
Fig.2b
Fig. 2. Infra-red spectra of petroleum fractions.
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E
F
E
F
80
aa
50
,"]
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38 R. FUDGE AND P. V. NICHOLAS [J.A.P.A., Vol. 8
100
90
30
EioF40
l0
20
0
0
7A
Tractor vapoLrrising oi
250
Fie.2c
WavelenSth pm
80
5ro
30
20
t500 250
Wavenumber
Fig, 2. Infra-rcd spectra of petroleum iiactions.
June, 19701 AN INVESTIGATION INTO PARAFFIN QUALITY 39
. Furfural polymerises on exposure to light, and its apparent concentrationin a. marked paraffin may fall. Consequeitty the quiniiirin concentration isused to estimate the level of ,.other paramn,,. fn. -irlmu. quantity ofgu.rri1"Ill requ-ired in paraffin is 1.75 pglml but to allow Jor up to doublethis addition.a figure of 3.50 pg/ml was usid to calculateihe vatues in Table V.r nrs rs consrdered to grve a reasonable degree of benefit to the supplier.
TABLE VESTIMATED COMPOSITION OF MIXED PARAFFIN SAMPLES
"Adulteration" with "other paraffin', may arise by intent or by contamina_tion. -The latter may occur at various stages and de a". i" the interchange
of fuels in storage tanks, or incorrect use-of dyes and markers. A limit off.O fe1 991r of-"other paraffin', could be held to indicate iadulteration,,,
sincethe addition of less would not be economically beneficial.
. .k3nlntiol of the. analytical data in Tabje IV, with particular referenceto the Infra Red transmission and Smoke point, illusirates that the ..other paia-ffin", where^present, is premium in quality. An exception is sampte g where thepresenc€ of regular grade paraffin is indicated. Simple 2l did not contain:T..11j1.-l,j:
Aladdin pink dy-e, and the dara illustrate, ttut tte fuer h soreiyregurar grade,' as are samples 40 and 43. The Smoke point values are a furtheimeasure of the aromatic content and substantiate these conclusions.
, I!".]4r Red Spectra (Fig.2 a-d) show the difference in the absorptiondue to the increase in aromatic content from premium grade paraffin throughto petrol. The absorption band at 650_g50 cm-r shows t'he incieasing intensiiyof the characteristic aromatic substitution pattern. oitrerentiaiion ofl paramninto its grade is based on the intensity ofabsorption at gOjcmliana 1605 cm-1.At these wave numbers there is a significant change in the absorption intensitydue to the difference in aromatic content of p..iir. and reguiar grades. '
Specific Cravity tests provide little concluiive informatioriregariing adul-teratio^n of the pink paraffins examined,fgures for the genuine sariples r:angingfrom_0.777 to 0.779, and for the adultJrated sample's fro- b.zZS to O.ZA:.The Tintometer colour assessment produces some evidence to support adultera-,io? rin:: the, colour intensity_ is reduced by the addition- oi-non_dyed fuel.
I o obtain the char value and sulphur content involves the use of equipment
40 R. F'UDGE AND P. V. NICFIOLAS [J.A.P.A., Vol. 8
normally not available in a Public Analyst's Department and although it wouldbe useful to know these values a quality assessment can be made without them.Further evidence to differentiate grades of parafrn may be obtained fromdistillation data1, such as the percentage recovery at 2d0" C and the fina1boiling point.
The inconsistent Flash Points show that the figures are not so valuablein quality assessment as the Smoke Point and Infra Red data, although ffashpoint should be determined to ensure that it meets the B.S. minimum of100. F.Such variations in properties may depend on the nature of the refining appliedto the paramn.
ln order to study the effect of adding regular grade paraffin to premiumgrade, tests were carried out on mixtures of genuine pink paraffin and regulargrade fuel, with the results noted in Table VI.
TABLE VIANALYTICAL DATA FOR MIXTURES OF REGULAR AND
Regular Paramnpet (ent. hy tolune
0l02030405060708090
100
This information may serye as a guide in estimating the level of regulargrade paraffin in pink admixtures.
ConclusionsAnalysis to assess quality and detect adulteration of premium paraffin is
practicable. This is necessary, for although most producers' premium fuel isof good quality and suitable for use in space heaters, the iituation is un-satisfactory because inferior and adulterated fuel is being sold. An articleentitled "Premium for Safety" appearing in a recent edition of the OmcialJournal of the Oil Appliance Manufacturers Associationl2 contained the state-ment that "only premium fuel should be used in an oil heater,,, and that theprincipal test for quality is always the Smoke Point, when comparing paramnsin this country. The article also indicated that an increasing number bf shop-keepers and hawkers are selling suitably dyed regular grades of paraffin ispremium quality.
A committee, on which the Institute of Petroleum, Appliance Manufac-turers and Weights and Measures departments are represented, is meeting atpresent to establish a British Standard for premium paraffin.
PREMIUN'I PARAFFINSInfra RedColour, Transmission atRed Yellorv Snloke Point 805 cm-r 1605 cm 1
June, 19701 AN INVESTIGATIoN INTo PARAFFIN QUALITY 4I
3.
_ The-comments made by the Consumers' Associationll adequately summarisethe action required to protect the collsllmer:
"Deflnite standards need to be set up for premium par.affin and aclear indication should be given of which type is being iold. Furtherpolicing is needed, even though Weighis and Measures lnspectors havealready prosecuted in a number of cases.,,
The Authors thank the Gloucestershire County Council Weights andMeasures Department for co-operation in sampling; Shell-Mex and B.p. Ltd.for technical information; Mrs. J. Graveling for her analytical assistanceand Mr. E. G. Whittle, the Scientific Adviser, for permission to publish thispaper.
Referenees1. Wood,,E. C., "Monthly tsulletin of rhe Association of public Analysts,,, London, 1969,p. 161 lPriwte circulation\.2. "Mini\rry ol Delence Spccificarion: DEF 2403-A. Kerosene (Burning Oil),,, H.M.S.O.,
London- I961.
4.
5.6.7.8.9.
10.11.12.
"Briri)h SlandirJ ll00 : 19b3. Specjficdljon-for Kcrosene rparamn) for use in UnflueJ SpaceHcalers ( oollng and Boiling ApplixncE. for Donreslic L.e". Briti!h Slandard, ln\tiluiion,?. Park Srreer. London W I
"british Standa;d 2869. t96'7. perroleum Fucls for Oil Engines and Burners. DomesticFuel Oil, Class C". B.itish Standard! lnsritution,2. park-Srrcet. London. W.l.*Renort ol rhe Corernment Chem,\1. rlq67)". H.\4.S.O., London, l96g n. J0.
I reld. K.. and Cod \. E. W.. 4haly5t. tgob,9t,2R7.Harrisun. R. B..and Hecl.rn6n. L. 1.. Anal)rt.l96l. 86,566.Har.r.on. R. 8., Pallr311an, J F., and Ro.e. il. \.. Anatrr. t96l- 86 5f,t"Slaqdard Merhod. lor Te'ting Perroleum and ,rs projucr., l909', fhe lnslirure ol pelro_
leum- London.Shell-Mex and B.P. Lrd., Shell-Mex House, Srrand, London, W.C.2(pj.it ate CL,nmunication)."Which:"', The Consumers Association, London, 1969. p. 3l l."OA,\4A Ne"s: No. t7", Thc Orl Appliance Manufaciuiers'Association, Londoo, January,
1970.
p.A.P.A., Vol. 8
A Comparative Evaluation of the A,-Tetrahydrocannabinolcontent of Cannabis Plants
by M. J. or. Flussnr MeuNoen(Laboratory of the Govemment Chemist, London, S.E.l)
An evaluation of the A0-tetrahydrocannabinol content of cannabis seed_lings and mature plants has been achieved by comparative T.L.C. of theisolated A0-tetrahydrocannabinol component following visualisation witha Fast Blue B spray. Other components have some value in determininggeographical origin of cannabis plants.
, The chemical composition of cannabis and its resin has been the subjectof considerable analytical and theoretical study. Much of this work is eitherinconclusive or conflicting. Thus the statements that the male plant does notproduce resin (Bredemannl and Murphyr) are in direct conflict with those ofValle and colleaguess, who concluded that, on a weight basis, tliey were equallyactive. Similarly, the biogenesis of tetrahydrocannabinol (THC) is disputed'.The discovery that all parts of a cannabis plant (except lignified items) wouldre_spond to a simple field test and a modified Duquenois reagenta,i, regardlessof the country of origin or gender of the cannabis plant, hai led to a furtherstudy of the major components by thin layer chromatography (TLC)6. Thisanalysis is rapid and has ample sensitivity to monitor single flowers, seedhusks or a lew square millimetres ol leaf. Thirty such examinations can becarried out on the same 200 mm width sheet with ease, thus eliminating someofthe subtle differences in chromatographic conditions in a series olestimitions.
Proced.uresThe TLC conditions operated were those prer,iousll described6. Eastman
Chromagram Sheet 6061 was used throughout uith either toluene or xyleneas the mobile phase.
For qualitative work, sheets measuring 100 mm x 50 mm were used,and 400-ml beakers covered with inverted petri dishes (or not covered at all)as developing ranks. For quantitative work. sheets measuring 100 mm200 mm were used in conventional, fnll-sized and covered tanks; in eithercase, the solvent travels to the top ofthe sheet (about 95 mm), in approximately30 minutes.
PREPARATION OF THE SAMPLE
Many of the samples were too small for a normal, bulk-sampling methodand were treated individually as follows. The herbal material was translerredto a small test tube and thoroughly crushed with a small glass rod, finallypressed into a wad and the glass rod removed. Sulficient light petroleum ether(boiling range 40'-60" C) was added just to cover the wad. The mixture was
M. J. DE FAUBERT MAUNDER
June, 19701 CHEMICAL COMPOSITION OF CANNABIS
stired with a pointed glass rod until homogeneous and allowed to stand for5 min., the tube being firmly corked. At the end of this period, any solventlost by evaporation was replaced, the mixture remixed, and the wad recom-pressed with the original glass rod. The herbal wad compresses further thanits original size after soaking, leaving a clear supernatant liquid suitable fordirect sampling without clogging the micro-pipette.
Micro-samples, for example, single flowers, were treated to the samesampling procedure except that solvent losses were made up as they occurred,so that the sample did not dry out at any time. It was not found possibleaccurately to weigh or measure an aliquot of solvent to add to the sample,with the volatile solvent used, and thus measurement by visual volumes wasadopted. Changing to a less volatile solvent caused an unacceptable loss ofresolution in spotting the sample due to solvent spread on the sheet.
SPOTTING
A1l samples were spotted on to the sheet in multiples of 0.5 pl, maintaininga maximum spot diameter of 1 mm. Spots in excess of 1 mm in diameterwere nol ulilised for quantitative measurements.
VISUALISATION
Developed chromatograms were allowed to dry naturally in air. The chromo-gen was freshly prepared for each batch of chromatograms by diluting a 0.1 percent. aqueous solution of Fast Blue B salt with reagent grade methanol (l : 3),and spraying it on to the chromatogram with an intensity sufficient to dampenbut not soak the sheet. After allowing the sheet to dry naturally in air, thedeveloped spots were measured.
The volume of sample applied was adjusted in subsequent expedments toapproximate to the area and intensity of a standard spot. Calculations weremade from a series of these standard spots by interpolation.
Where appropriate, the chromatogram was examined under ultravioletradiation of wavelength 360 mp before spraying with the chromogen.
REFERENCE STANDARD
From a typical, 500-9 sample of Nigerian herbal cannabis,25 g of fruitingtops were selected at random, and a solution was prepared from this bulkedsample in the same way as the samples for analysis. The supernatant liquidwas poured off and stored in a well-stoppered vessel in the dark.
A solution containing l0 mg of A,-THC per ml in light petroleum etherwas prepared as an absolute reference standard.
CONFIRMATION OF IDENTITY
Confirmation of the identity of chromatograph spots, and of the identityor origin of a cannabis sample, was obtained by preparing a chromatographof the sample in two dimensions. For this purpose a 2 per cent. solution ofdiethylamine in toluene was used as the second solvent system.
43
44 M. J. DE FAUBERT MAUNDER [.A.P.A., Vol. 8
Results
QUALITATIVE AND DIAGNOSTIC PATTERNS
THC is well resolved from the other major components of cannabis, fiveof which have been noted previously6. Toluene in an equilibrated tankproduces the following Rf values:
TABI,F T
R{ VALUES OF THE ACTIYE PRINCIPLES OF CAN\ARISComponent
Cannabidiol (CBD)A'.THC ..Cannabinol (CBN)"Unknown" I .."Unknown" 2 .. ..
+ After spraying with a nethanolic solLltion of Fast Blue B.
The "pattern" produced by these flve spots may be used in a diagnosticmanner to identify tl.re geographical origin of the sample, provicled this patternis related to the gross physical appealance of the sample. The pattern of spotsvaries in the relative intensity and the presence of minor componenls. Extraspecificity is possible with two-dimensional TLC using a 2 per cent. solntionol diethylaminc in Loluene as the second solvent. A host ol new unknown,and extla diagnostic spots and streaks are developed from the starting point,and some of the five major spots, in particular, the rrvo "Unknowns" 1 and 2are revealed as having been overlapping spots rLsing the first solvent. lnter-ference with the THC spots was not noted rvith the samples used lor quantitativeestimations-
Cannabinol (CBN) is present in r,ery small amounts in fiesh Middle-Eastern plants and resins, and forms a major component in n:arlv every otherloreign source, but English-grown plants are a notable e]:ceptjon uitless grownin a warm situation. Thc CBN content of a prcpil-ed soluiion incrcasesgradually with time while the le-THC content decreases. Samples of herbalmaterial, resin and prcparcd solutions, do not deleriorate very rapidly rvhenstored away lrom strong sunlight, alter an initial drop in lo-THC contentover the first lew months. Lerncrr found ihat the _\r-THC content droppedby 5 per cent. per month, and badly-stored material was found to deteriorateat a rate consistent r.vith this in the present investigations.
Cannabidiol (CBD) is not detectable in a number of samples, although itis a major component lrom plants and resins grown in the Middle East. Thetotal absence of CBD from a number of diverse samples, particularly plantsgrown South of the Sahara, even after a storage ol several years, suggeststhat it has a different biogenesis and is only produced by certain sr:b-speciesof cannabis. Most ol the analytical work, and the theory derived from it,appears to have been based in the past on Hashish ol Middle East origin,which is particularly rich in CBD.
The "pattern" of components lrom different portions of the same plantmay vary. This effect would be entirely masked by any process of comminution
June, 19701 CHEMICAL COMPOSITION OF CANNABIS 45
of the entire sample before analysis. The "pattern" variations may be asextreme as the complete absence of one component, and the identity of verysmall herbal samples, with respect to geographical origin, was not possibleunless the gross physical appearance ofa large sample (in excess ol I00 mg) couldbe determined. Resins already represent a composite sample and in this casesampling error is less important.
The only componcnts common to all samples examined were Ae-THC andthe "Unknowns" I and 2. In a number ofcannabis plants grown in England,these were the only components detectable with Fast Blue B spray, althoughoccasional caroterroids were detected visually, and other spots with ultravioletradiation. The "Unknorvns" I and 2 appear to be present in an approximatelyconstant proportion to the THC content, with a total area and intensitycomparrble wirh the THC <pot.
Co\-TENT oF le-trTuHyonocANNABINoL
The le-THC is not immcdiately detectable in fresh yor-rng leaves. Apartfrom carotcnoids and the occasional spot shown by ultraviolet radiation, nospots are developed by Fast BILre B spray with fresh young leaves lrom Englishplants, except for a pink streak from thc starting point to an Rt value ofapproximately 0.2. and the "Unknowns" I and 2. However, the samc leavesdried naturally in air lor a few da1,s, or a light petroleum extract allowed toevaporate and stand. rvill contain lr-THC, and this was shown in a ser.ies ofchromatograms orer a period of days. As the -\r-THC spot appears, andincreases in intensity. the pink streak decreases in intensity, and finally dis-appears. A similal effect rvas noted with very lresh samples of cannabis resin.where a strong ofange streak from the starting point to an Rf value of approxi-matel), 0 2 is a characteristic of and may not be noted for the same samplea ferv weeks later.
-\.'U-THC was detected in all non-lignified parts of thc plant after drying,and in mature leaves and flowers ilr the living plant, regardless of the maturityor gender ofthe plant as a lvhole. [t is even detectable in germinated seedlingswithout fully-developed cotyledons if these are dried for a few hours. Seed-lings, regardless of the features exhibited by the mature parent plant, alwayscontain detectable amounts of A9-THC before other. components, and at thisage. growing conditions can be standardised in a laboratory.
The A'g-THC content ol a range of samples has been estimated and rcturnedas a percentage of a standard "flowering top" from an authentic Nigeriansource. Nigerian cannabis has a Ar-THC content typical of most samplesavailable on the illicit market and contains very lew other components de-tectable with Fast Blue B. The results from sub-samples of this standardsource, before bulking, varied within a range of 10 to 200 per cent. of thefigr:re for the bulked samples. A typical series of nine sub-samp.les gavepercentage figures of-25; 175;75:50; 150; 100t 100; 100; l0; against abulked sample, that is, more than a ten-times variation in magnitude. This
?
4t) M. J. DE FAUBERT MAUNDER [J.A.P.A., Vol. 8
is an indication of the variation possible from different parts of the same plant,particularly where the ratio of components is concerned in elucidating thecharacteristic "patterns" of components. Bulked samples produced consistentresults within the accuracy of the method, but since there are subjective errorsin sampling, and handling losses before receipt are unpredictable, a moresophisticated method of quantitative sample preparation than that specifiedabove is considered unjustified. The absolute accuracy of the figures in Table IIcan have no real meaning when variations between samples are also con-sidered, but the relative order of magnitude of the figures presented is anindication of the average A9-THC content to expect from a range of samples,It will be noted that some samples, grown under conditions previously con-sidered to be adverse, can contain as much A'0-THC as samples grown undergood conditions.
Conclusions
A'g-THC is the first cannabinoid component to be detected in growingcannabis plants and is frequently the only major component, apart from twounknowns, to be found in plants grown in England. Male plants, and plantsgrown under very adverse conditions, can contain Ae-THC in amounts com-parable with those in plants grown in hot climates. This principle is detectablein seedlings, and in leaves without resin glands, and an apparently decreasingcontent in the same leaves during growth is ascribed to dilution of an initialconcentration as the leal matures.
The absence of appreciable amounts of other cannabinols may accountfor the poor response to classical tests for "potency". Cannabidiol appearsto play no part in the biogenesis of Ag-THC, and cannabinol is a decompositionproduct of Ae-THC.
Cannabis from various geographical areas may be identified from the dis-tinct chromatographic "patterns", provided this is related to gross physicalappearance. The chromatographic pattern formed by the presence of minorcomponents, and the relative intensities ofthe three major components A,-THC,CBD, CBN, is different for each major growing area, and can confirm thegross physical appearance, which is frequently quite distinctive. The patternmay be distorted with small samples due to the natural variation in a plantwith different parts at various stages of maturity, and a bulked sample olat least 100 mg is recommended for reproducible results with herbal material.Figures obtained with resins are more reproducible.
Extra specificity for identifying geograpl.rical origin is provided by two-dimensional chromatography. An incidental conclusion drawn from thistwo-dimensional work is that analysis of cannabis involving thin layer chro-matography with solvent systems including diethylamine is unsuitable forconfirming the presence of the major cannabinoids because of the ovedappingof a host of unknown spots and streaks of similar Rf value and colour.
June, 19701 CHEMICAL COMPOSITION OF CANNABIS
rABLE IITHE AO-TETRAHYDROCANNABINOL CONTENT OF SAMPLES OF ENGLISH
CANNABIS RELATIVE TO A TYPICAL NICERIAN "FRT'ITING TOP''GrowingConditions Ag-THC*
Natural (1969) f100Grown in laboratory (1969)
I5
l5Killed by drought 2
25Low illumination 2Grown in Essex during the very
wet and cold Summer of 1968in the open _
Grorvn in Essclduring the verywet and cold Summer of 1968in the open _
Clolvn io Liverpool in a green-house during Sumnrer of 1965
Grown in laboratory (1969)
Grown in Surrey in a greenhouseduring Summef of 1962
Grown in laboralory (1969)weak seedlings did not survive
the fi.st-leaf stage10. Small seedlings ..
small leaflarge leaf
ll. Fruiting plant ..fruiti.g topsmall leaf
12. No. ll siblings ..
.. Grown in laboratoiy (1969), from
. . seed ofJamaican origin
5 nir nir2".. One of manv seized illi.it im-
ports from"South Africa75
.. Crorvr, in laboratory (1969): " ,rro"
nil tracei" "t
47
l.)
6.
7.
flowe$ . .
small leafflowering top .. ..lrurtlng topseed husks
9. No. 7 siblingsmall seedling .. ..
CBDnil
CBNstrong
trace
nil
strong strong
SampleNigerian: "fruiting top"No. I siblings .. ..
small leafflowering top ., ,.fruitiag top .. ..seed husks
No. 5 siblingsmall seedling.- ..
Flowering female plant
nil nil
251"5"
501
25
10075755025
5
252
202020
these plants proved io liemonoecious, beadng both maleaDd female flowers with fruit
Same pattem asNos. 6, 9 and l0
* Expressed as a percentage o[ sample No. l.. 1 This stand-ard-corresponds- to a solurion of about 5 mg of Ag-THC per ml. At an averagebulk.densiry ol q.9^c_p-ef ml for compressed herbal cannabis. the staridard is approxirnateJyequal to 17 mg of A'-THC per gramme of Nigerian herbal caonabis.
I Extra unknown spot with Rr value intermediate between Ag-THC and CBN and havitrg thesam€ colour and intensity as A0-THC.
Referencesl. Bredemann, G., Schwanitz. F., and von Sengbusch, R.. Bull. Narcot.,l956, E(l), ll.2. Murphy, H.B. M., Bull. Nar.or,, 1963, I5(l). 15,
1. yuf]9, {.R., Lapa,-A. 1., and Barros, G. G., l. Phorm. PharmacoL, 1968, 20,798.4. de Faubert Maunder, M. J., J. Assoc. Publ, Analysts, 1969.7.24,'5. de Faubert Maunder, M. l.,Bull. Narcot., 1969 2l(41,37.6. de Faubert Maunder, M. !., J. Pharm. Pharmacol., 1969,21.134.7. Lemer. P.. Bull, Narcor., 1969,21(3), 39.
-
48 M. S. GREEN p.A.P.A., Vol. 8
Notes on Clearing Methods for the Determinationof Nitrate and Nitrite in Canned Baby Foods
Dy M. S. GnmN
(County Laboratory, County Hall, Preston, Lancs.)
Details are given of a modified clearing nrethod prior to the determinationof nitrite and nitrale in ca ned baby foods. The results of the analysisof 22 baby foods are tabulated.
As a result of work published by Fogdenl, the Lancashire laboratory tookan interest in the subject and evidently had less initial success with the methodof Follett and Ratc1iff'z than the members of the Leicestershire laboratory.
In the first series of analyses of canned baby foods for nitrate content,the method of Follett and Ratcliff which was originally developed for meatproducts was employed. A few of the baby foods gave difficulty in preparingclear extracts and gave very high results. In endeavouring to repeat and confirmthese figures, widely varying results could be obtained from slight variations inthe clearing procedure. This suggested that the potassium aluminium sulphateclearing agent left varying amounts of interfering compounds in solution. Apaper by Schall and Hatchef was published at this time which also stated that"existing methods, when applied to the determination of nitrate in animalfeeds gave erratic results, usually with a gross positive error, due to inter-ference from soluble proteinaceous material."
Adriaanse and Robbersa use zinc sulphate and ferrocyanide as clearingreagents for meats and soils and state that no loss of nitrate is caused providedthat the zinc solution is used first. They also warn that ascorbic acid interferesin the nitrite determination and they remove this with active carbon. Thisprocedure may possibly be necessary when dealing with some of the dried,fortified baby products.
A modified method, based on the methods of Follett and Schall is givenbelow. It was found that duplicates became more consistent and recoveriesexceeded 90 per cent. An EDTA buffer is used, having the advantage of beingable to remove cadmium salts from the column during the reduction byforming complexes, thus eliminating the 20-30 min. acid-water-buffer washingsteps between samples.
Reagents
1,. Extracting solution: Dissolve 50 g of CdCl, and 50 g of BaCl, indistilled water aod dilute to I litre. Adjust to pH I with hydrochloricacid.
2. Buffer solution: Dissolve 37 g of EDTA di-sodium salt in distilledwater, adjust to pH 9.6 with sodium hydroxide solution and diluteto 1 litre.
I
June, 19701 NITRATE IN CANNED BABY FOODS
3. Column eluent: Dilute 25 ml of the buffer solution to 500 ml withdistilled water.
4. Sulphanilamide solution: 0'5 per cent. Dissolve 1'25 g of sulphanil-amide in 250 ml of hydrochloric acid (l * l).
5. Coupling agent: A,0.5 per cent. aqueous solution of N-(1-Naphthyl)-ethylenediamine hydrochloride, Store in a brown glass bottle in arefrigerator.
7. Sodium hydroxide: A 10 per cent. aqueous solution.
Metl;odMix 10.0 g of the food with 140 ml of water and 50 ml of the extracting
solution, and allow to stand for at least t hr., stirring occasionally. Addl0 ml of 10 per cent. sodium hydroxide solution and filter immediatelythrough a Whatman No. 4 fllter paper.
DETERMINATION OF MTRATE
Mix 45 ml of the filtrate with 5 ml of buffer solution. Accuratelymeasure 20 ml of this mixture on to the cadmium reducing column. Washthe column with the dilute EDTA eluting solution and collect 100 ml ofeluate. Transler 10 ml of the eluate to a 50-m1 volumetric flask and diluteto approximately 40 ml. Add 5 ml of sulphanilamide solution and allowto stand for 3 minutes. Add 2 ml of the coupling solution, make tovolume and mix. Allow the mixture to stand for 20 minutes, then measurethe extinction ofthe solution at 540 m1, using a 1-cm or 4-cm cell. Convertthe readings to microgrammes of NOr- by reference to a calibration graphprepared by similarly treating aliquots of a standard sodium nitrite solution.A suitable range of concentrations of the standard would contain theequivalent of 1 to 30 pg of NOr- (for a 4-cm cell) or from 10 to 120 pg(when using a 1-cm cell). A blank determination should be run each dayas this tends to increase as the column becomes contaminated. Beforeusing the column again, after being stored, it is necessary to wash it with25 ml of 0.1 N HCl. This is followed by the dilute EDTA eluting solutionuntil tests on l0 ml of the eluate show low and steady nitrite readings.The nitrite in the reduced solution is corrected for the reagent-column
blank and also for any nitdte present in the cleared solution before reduction.It is finally converted to the equivalent of nitrate (NOr-) in the original sample.Allowance is also made for the original moisture content of the sample, thisbeing determined separately.
DETERMINATION OF NITRITE
A suitable aliquot ofthe original filtrate is tested directly with the sulphanil-amide and the coupling reagent as described for the determination of nitrate,the extinction of the solutions for light of wavelength 540 mp being employedas before.
49
50 M. S. GREEN [.A.P.A., Vol.8
ResultsThe nitrate contents of 22 samples of canned baby foods examined by this
modified method are shown in Table I. The nitrite content (as NOr-) wasless than 5 parts per million in every case.
TABLE IMTRATE CONTENTS OF SOME CANNED BABY FOODS
Nitrate content (as NOi)parts pet million
Type of Baby Food
Tomato and Beef .. ..Chicken BrothVegetable and Beefveal Dinner. .
Vegetables and BeefVegetables and Be€f
t197193l10
732724422
2005
15067
160l533332l4l27
230
Vegetable and BaconVegetable and Lamb BrothCarrots
Tomato and BeefMixed vegetables ..Baked Ham DinnerBeef DinnerOxtail and VegetableJunior Vegetables .. ..Caulifl ower Cheese (Instant)
References
l, Fogden, L. A., and Fogden, M. W., "/. lsroc. Publ. Analystt. 1969, 1.133,2. Follett, M. J., and Ratcliff, P. W.. J. Sti. Food Aeri.., 1963. 14. 138.3. Schall, E. D., and Hatcher, D. W.,./. ,ls.roc. O.ll. Anal!,t. Chefiists, 1968,51.763.4. Ad aanse, A., and Robbcrs, J. 8., "/. Sri. Food A?tic.. 1969. 20.321.
7
June, 19701 BOOK REVIEWS
Book ReviewsCsslflcll AN,q.Lvsrs or- INDUSTRTAL WArERs. By JAr'{Es W. MCCoy. Fp. 292 * xi, New
York: The Chemical Publishing Company. 1969. Price $15.00.
This useful iittle book shoulcl find a place on the shelves of every laboratory which hasto deal with industrial waters. It provides a wealth of information on both the theoreticaland practical aspects of the subject and will be cl especial interest to those for whom suchanalyses are only a small and occasional part of their work. The section on the Analysisof Deposits should be olpalticular interest to Public Analysts and other consultant chemists.
The book is divided into four parts. The flISt deals with the theory of water treatnentand provides a brief introduction to the basic principies involved. Part Two is concefiredwith the analysis of industrial waters and the interpretation ol results; the determinationof some fifteen constituents is given in some detail. The third section relates to the use ofspecial procedures, inciuding the analysis of foul waters and includes methods for theevaiuation of ion-exchange resins.
The fourth and final part sets out a scheme for the systemic anaiysis of scales, sludgesand deposits and helps to shorten the task by indicating the most likely constituents of de-posits from various parts of the system. This is based on the author's own experienceand covers most of the materials Iikely to be encountered.
The book is intelligibly written and appears to be free from major misprints: each ofthe four sections is followed by a copious list of rclerences. Nlost of the procedlrres arebased o1,l ordinary wet methods of analysis and the use of physical instruments is confinedto those likely to be found in the smaller laboratory. The size and format of the volumemake it admirably suited to bench use. S. J. BusH
ALL ABour DRUGS. By FRA\Z BERGEL and D. R. A. DAvrEs. Pp. 203 * x. London:Thomas Nelson and Sons Ltd. 1970. Price 42s.
This book atten'rpts the formidable task of fullilling the promise of its title with referenceto thc misused and addictive drugs in a little over 200 pages. Nine chapters each dealingwith different groups of drugs from stimulants, tranquilliserc and hallucinogens to cannabis,opium and cocaine, accoLlnt for four-fifths ofthe book, the remainder consisting olrcferences,index and five appendices, three of which give tabulated information of drug soruces, nlodeof action, legal controls and chemical names.
The book is aimed primarily at the general public with the intention of b dging the gapbetween them and the meCical and social workers who have the unenviable task of sortingout the chaos resulting fron drug misuse. Clearly the principal difficulty lies in the simpli-fication of a complex subject, educating the reader in medico-scientiflc and "drop-out"jargon whilst maintaining an interesting and readable script. On all these courts the authorsare to be coogratulated, the wealth of jnformatioo packed into these pages makes the booka fltting addition to the Iibrary shelf ofany organisation whose activities are likely to becomeinvolved with this problem. Inevitably the non-professional reader will still require agenuine thirst for knowledge if he is to stay the course.
In addition to details of habituation, toierance, addictiorl and dependence which mayresult from the misllse of the drugs considered, each chapte! gives the origin, history, medi-cinal use and pharmacological action together with the national and interrational legislationused for their control. The addicted reader may then obtain further supplies of informationvia the very conlprehensive Iist of rcferences.
Once criteria, againstwl'rich misuseable diugs may be evaiuated, have been established, thereader is obliged to consider alcohol, tobacco, aspirjn, barbiturates and er€n the caffeinein tea and cofee, which results in a better appreciation of the problem and the realisationthat many possiblc avenues of potential drug misuse remain.
Appendix A, "Notes on Chemistry and Analysis", gives some useful textbook data onthe internationai measurement of proof spirit and the percentage of active principle in
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52 BOOK REVIEWS [J.A.P.A., Yol. 8
naturally-occuffing drugs together with notes on the chemical structure of the syntheticcompounds covered. However, in the absence of chemical formulae and within the limitationof the 13 pages allotted to it, the non-graduate is unlikely to suryive the chemistry. Theanalytical notes are of little value, often only listing (without references) instrumental tech-niques by means of which tbe assay may be caEied out.
Public Analysts (not surprisingly) are referred to several times, a reminder that theycan become professionally involved in these matters at any time. On these occasions oneis completely dependent upon the quality of background information given-this bookhelps to complete that background and forges the link between the "drop-out" societyand the toxicological textbook.
The reviewq found this book, when taken in conjunction with caffeine and nicotine,to be most interesting reading. A. J. HARRISoN
l
ERRATUM
In the issue Vol. 7, No. 3, (September) 1969, figure 4 of an article by I. M.Mackie, was incorrectly printed. The corrected figure is printed below.
