Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. इंटरनेट मानक “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda “Invent a New India Using Knowledge” “प0रा1 को छोड न’ 5 तरफ” Jawaharlal Nehru “Step Out From the Old to the New” “जान1 का अ+धकार, जी1 का अ+धकार” Mazdoor Kisan Shakti Sangathan “The Right to Information, The Right to Live” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” IS 3025-45 (1993): Methods of sampling and test (physical and chemical) for water and wastewater, Part 45: Sodium and potassium [CHD 32: Environmental Protection and Waste Management]
Transcript
Disclosure to Promote the Right To Information
Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.
इंटरनेट मानक
“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda
“Invent a New India Using Knowledge”
“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru
“Step Out From the Old to the New”
“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan
“The Right to Information, The Right to Live”
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”
“Invent a New India Using Knowledge”
है”ह”ह
IS 3025-45 (1993): Methods of sampling and test (physicaland chemical) for water and wastewater, Part 45: Sodium andpotassium [CHD 32: Environmental Protection and WasteManagement]
IS 3025 (Part 45 ) : 1993(Reaffirmed 2003)
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Indian Standard
METH.ODS OF SAMPLING AND TEST( PHYSICAL AND CI-IEMICAL ) FOR WATER
This Indian Standard ( First Revision) was adopted by the Bureau of Indian Standards, after thedraft finalized by the Environmental Protection Sectional Committee had been approved by theChemical Division Council.
Industrial wastes invariably contain significant quantities of sodium. Sodium salts beingextremely soluble get leached early from soil and rocks and tend to remain in solution. .
Sodium is not particularly significant in potable water except for those having an abnormalsodium metabolism. For high pressure boiler feed water even trace amounts of sodium are orconcern.
Potassium rocks, such as silicates, are more soluble in water than sodium forms. Most naturalwaters contains-less than 20 mgll of potassium, but water containing several hundred milligramsper litre are occasionally found. Potassium is essential to animal nutrition.
In the preparation of this standard. considerable assistance has been derived from standardmethods for the examination of water and waste water published by American Publi c HealthAssociation, Washington. USA, 16th edition, 1985.
The composition of the technical committee responsible for this preparation of the standard isgiven in Annex A.
For the purpose of deciding whether a particular requirement of this standard is complied with,the final value, observed or calculated" expressing the result of a test or analysis, shall be roundedoff in accordance with IS 2: 1960 'Rules for rounding off numerical values (revised)'. Thenumber of significant places retained in the rounded off value should be the same as that of thespecified value in this standard.
IS 3025 ( Part 45 ) : 1993
Indian Standard
METHODS OF SAMPLING AND TEST(PHYSICAL AND CHEMICAL) FOR WATER
AND WASTEWATERPART 45 SODIUM AND POTASSIUM
( First Revision)1 SCOPE 5 FLAME PHOTOMETRY METHOD
5.1 PriacJple
A flame photometer measures photoelectricallythe intensity of colour imparted to the flame ofa Meker-type burner where the sample isintroduced into the flame under carefullystandardized conditions. The intensity of colouris proportional to the sodium/potassium contentin the sample. Sodium and potassium aredetermined at a wavelength of 589 nm and766·5 nm, respectively.
5.2 Interferences
5.2.1 Radiation interference caused by elementsother than those being determined is the chiefcontributing factor for error in flame photometry. Of the elements encountered in theseanalyses, the major effect is due to interferenceof one alkali-metal on another. Some effectsape 'positive and some are negative, Amongthe other common ions capable of causinginterference are CI-, SO.I- and HC03- inrelatively higher concentration. The foreignelement effects cannot be' entirely compensatedwithout employing calibration standards closelyduplicating the composition of the sample orby applying an experimentally determinedcorrection in those instances where the samplecontains a single important interference. However, the effects may be minimized by operatingat the lowest practical sodium or potassiumconcentration range or by removal of theinterfering elements, For example, aluminiumhas a depressing effect on alkali-metal emission,which may be of serious consequence. Theamount of aluminium normally present in waterhas been found to have a negligible effect onalkali-metal determination. However, aluminiumin waste waters should be removed from thesolution prior to flame photometry if itsconcentration has been found by preliminarytests to exceed that of the alkali metal beingdetermined.
Title
Methods of sampling and test( physical and chemical) forwater and waste water: Part 1Sampling (first revision)Glossary of terms relating towater, sewage and industrialeffluents, Part 1Glossary of terms relating towater, sewage and industrialeffluents, Part 2
7022 ( Part 2 ) :1979
7022 ( Part 1 ) :1973
The Indian Standards listed below are necessaryadjuncts to this standard:
IS No.
3025 ( Part 1 ) :1986
3 TERMINOLOGYFor the purpose of this standard, definitionsgiven in IS 7022 (Part 1 ) : 1973 and IS 7022( Part 2 ) : 1979 shall apply.
4 SAMPLING AND STORAGE
The sampling and storage shall be done asprescribed in IS 3025 (Part I ) : 1986. Acidifythe sample to pH 2 with concentrated nitricacid. Store all samples/stock solutions inpolyethylene bottles.
This standard prescribes following three methodsfor determination of sodium and potassium:
a) flame emission photometric method usingeither a flame photometer or an atomicabsorption spectrophotometer in theflame emission mode;
b) atomic absorption spectrometric methodusing an atomic absorption spectrophotometer in flame absorption mode; and
c) gravimetric method for determination ofsodium and colorimetric method fordetermination of potassium.
2 REFERENCES
1
IS 3025 ( Part 4S ) : 1993
5.2.2 Self-absorption causes the curve ofintensity versus concentration to decrease inslope at higher concentrations tending to reduceaccuracy. Bracketing the unknown by knownstandard solution and inter-polar ing linearlybetween the two minimizes this interference soas to render it practically negligible.
5.2.3 Suspended matter which may interferemechanically by clogging the burner shall beremoved by filtration prior to analysis. Organiccolouring matter docs not cause interferenceand need not be removed.
5.2.4 Flame photometers operating on theinternal standard principle may require addinga standard lithium solution to each workingstandard and sample. Follow the manufacturersinstructions for the optimum lithium concentration.
5.2.4.1 Incorporate a non-ionic detergent in thestandard lithium solution to assure properaspirator function when using the internalstandard type flame photometer.
5.1.5 In the internal standard technique, potassium interferes with the sodium determinationif the potassium to sodium ratio is higher thanS : 1 and sodium interferes with the potassiumdetermination if the sodium to potassium ratiois higher than 5: 1. Calcium interferes if thecalcium to sodium/potassium ratio is higherthan 10: I. In such cases an approximateconcentration or the interfering ions may beadded to the sodium/potassium calibrationstandards. Magnesium interference does notappear until magnesium to sodium/potassiumratio exceeds 100 : 1.
S.3 Apparatus
5.3.1 Flame PhotometerEither direct-reading or internal standard typeor an atomic absorption spectrophotometer inthe flame emission mode.
5.3.2 Glassware
Rinse all glassware s with dilute nitric acid( 1 : 15 ) followed by several portions of deionized distilled water.
5.4 ReagentsUse deionized distilled water to prepare allreagents, calibrations, standards and dilutionwater.
5.4.1 Stock Sodium Solution
Dissolve in deionised distilled water, 2·542 g ofsodium chloride dried to constant mass at140C.C and make up to 1 000 ml with water.1 ml = 1 mg of sodium.
2
5.4.2 Stock Potassium Solution
Dissolve in deionised distilled water 1·907 g ofpotassium chloride dried at 110°C. and make upto t 000 ml with water, 1 ml == 1 mg ofpotassium.
S.4.3 Standard Lithium Solution
Weigh rapidJy 6·109 g of lithium chloride( uci ) or 9·93 g of lithium nitrate ( LiNO. )dried overnight in an oven at 105°C. Dissolvein water and make up to I 000 ml, 1 ml = 1 mgof lithium.
NOTE - Prepare a new calibration curve wheneverthe standard Ii thium solution is changed.
5.5 Procedure
S.5.1 Pretreatment of Polluted Waler and WasteWater Samples
Take 100 ml of sample in a beaker and add5 ml of concentrated nitric acid and evaporateto dryness. Repeat this operation once again byadding concentrated nitric acid. Dissolve theresidue in minimum volume of concentratedhydrochloric acid. Boil to dissolve, dilute to50 ml with water, filter and make up to 100 mi.
NOTE - No preliminary treatment of sample isneeded except filtration through an 11 em ashlessfilter paper of medium retentiveness jf the samplecontains only suspended rna tter as an impurity.
5.5.2 Precautions
Place the instrument away from direct sunlightor constant light emitted by an overhead fixturein an area free of drafts. dust and tobaccosmoke. Avoid contamination from corks, filterpaper, perspiration, soap, cleansers, cleaningmixtures and inadequately rinsed apparatus.
5.5.3 Instrument Operation
Follow manufacturer's instructions for selectingproper photocell and wavelength, adjusting slitwidth and sensitivity, appropriate fuel and airor oxygen pressures and the steps for warm-up,flame background, rinsing of burner, aspiratingand igniting samples and measuring emissionintensity.
5.5.4 Direct-Intensity Meaaurement
Prepare a blank and sodium/potassium standardsin stepped amounts by diluting the stock solutions described in 5.4.1 and 5.4.2 for any of thefollowing applicable ranges: 0 to 1·0 mgll, 0 to10 mg/l, or 0 to 100 mg/l, so that within eachrange there are equally spaced standards intenths of the maximum. Starting with thehighest calibration standard and workingtowards the most dilute standard, measureemission at 589 nm for sodium and 766·5 nm for
,potassium. Repeat the operation with bothcalibration standards and samples enough number of times to secure a reliable average readingfor each solution. Construct a calibration curve,by plotting emission intensity (scale reading)versus concentration of each calibration standard on a linear graph paper. Preferably use thebracketing approach described in 5.5.6. Determine sodium/potassium concentration of thesample solution from the respective calibrationcurve.
5.5.5 Internal-Standard Measurement
Add an appropriate volume of standard lithiumsolution to carefully measured volume of sample( or diluted portion), each sodium/potassiumcalibration standard and the blank, and thenfollow all the steps described in 5.5.4.
5.5.6 Bracketing Approach
From the calibration curve, select and preparesodium/potassium standards that immediatelybracket the emission intensity of the sample.Determine emission intensities of the bracketingstandards (one standard slightly less and theother slightly greater than the sample) and thesample as simultaneously as possible. Repeatthe determination on bracketing standards andsamples.
5.6 Calculation
5.6.1 For direct intensity measurement ( 5.5.4 )and internal standard measurements ( 5.5.5. ) :
Sodium ( or potassium ), Sodium ( or potas-mg/l = sium ) in mg/l in
portion x D
5.6.2 For bracketingapproach s?dium (B-A)(s-a)( or potassium), = ---- .----- --- +A X Dmgj l ( b - a )
whereB = sodium (or potassium) in upper
bracketi ng standard, mg/I;
A = sodium (or potassium) in lowerbracketing standard, mg/};
b = emission intensity of upper bracketingstandard;
a = emission intensity of lower bracketingstandard;
s = emission intensity of sample; and
( sample in ml + 1D = dilution ratio « Idistilled water in ml
L sample in ml J
5.6.3 Repeat the calculation for the second setof data and average the two values to obtainthe concentration of sodium ( or potassium ).
3
IS 3025 ( Part 45 ) : J993
6 ATOMIC ABSORPTION SPECTROMETRYMETHOD
6.1 Principle
This method js hascd on the fact that when asolution containing salts of sodium and potassium is introduced in the flame, the intensity ofthe transmitted radiation will decrease inproportion to the extent of the concentration ofthese clements in solution. A hollow cathodelamp made of the element to be determinedprovides the source of radiation. The applicationrange of th is method is 0·20 to 4·0 mg/l whenusing the 766·5 nm resonance tine for potassiumand 0·20 to 3·0 mg/l when using the 589·6 nmresonance line for sodium.
6.2 Interference
6.2.1 No chemical interferences have beenfound. Sodium and potassium are partiallyionized in air-acetylene flame (to suppressionization add potassium nitrate or potassiumchlor ide to give final concentration of 2 000 p.glml of potassium in the solution, itl whichsodium has to be measured and add anyone ofthe cesium nitrate, cesium chloride. sodiumnitrate and sodium chloride to give a final concentration of 1 000 p.g/ml of cesium or 2 000~g/ml of sodium as the case may be, in allsolutions including blank where potassium hasto be measured). Presence of appreciablecoucentrat ions of mineral acids in the solution,reduce the absorbance reading for both sodiumand potassium. Hydrochloric acid, sulphuricacid, nitric acid and phosphoric acid causedecrease in the reading. Influence of nitric acidand sulphuric acid is mainly due to 'changes inphysical properties and the aspiration rates ofthe solution. The influence of hvdrochloric acidand phosphoric acid is Que to the evaporationprocess in the flame.
6.1.2 Concentration of aluminium, phosphate,sulphate and silicate up to 160 mgj l do notinterfere with low concentration of sodium,namely, to 2 to 10 mg/}, But it is found thatslight decrease in absorption occurs in thepresence of high concentration of phosphates.But the same amount of aluminium, phosphate,sulphate and silicate do not interfere wirhpotassium, determination in the presence ofaluminium chloride ( 1M ).
6.3 Apparatus
Atomic absorption spectrophotometer in theabsorption mode, set up and operated accordingto the manufacturer's instructions, equippedwith an appropriate burner for air-acetyleneflame and hollow cathode lamps for sodium andpotassium determinations.
IS 3025 ( Part 45 ): 1993
100 to 400 200 to 800
Working range, pglm!r--.----A.----~
Sodium Potassium0·15 to 0·60 0·5 to 2-00-5 to 2·0 1-5 to 6·0
range shall be as below:War.length, nm
A
'Sodium Potassium589·0 766·5589-6 769·9
330·2 ) 404.4330·3 )
NOTE - By rotation of burner on S89 nm and589·6 om for sodium and on 766·' nm and 769·9 omfor potassium, measurements can be taken for 20 tojO I4/m1. Ho\\'ever. the working range and also thesensitivity may vary for different instrument• pecifica t ion.
'.5.5 Prepare calibration curve by plotting theabsorbance reading against the sodium (orpotassium) concentrations.
6,,5.6 Aspirate the test solution and read thesodium ( or potassium) concentration from thecalibration curve.
6.7 Calculations
Sodium (or Potassium). mgll = ex ~1
whereC: = sodium (or potassium) concentration
from the calibration curve, mg/l,Y = volume of the original sample taken for
analysis, ml, andVI = volume of the volumetric flask (100 ml).
7 GRAVIME1"RIC METHOD - FOR SODIUM
7.1 PriDclpleSodium is precipitated as sodium zinc uranylacetate hexahydrate, [ NaC.H.O•.Zn (C.H.O.)•.3UO. ( CIH~O. )1. 6H:lO] by adding a largevolume of zinc uranyl acetate reagent previously saturated with the sodium salt to a smallvolume of the concentrated sample.
7.1 IDterfereDce
Lithium interferes by forming a slightly solublesalt with the reagent, potassium interferes iCthereare more than 25 mg in the I ml solution beingtested. Organic acids, such as oxalic, citricand tartaric, interfere, as anions such as phosphate that give precipitates with the reagent.Sulphate must be absent when much potassiumis present because potassium sulphate is onlyslightly soluble in the reagent. If the potassiumand sulphate concentrations are known, themaximum possible error due to the precipitationof potassium sulphate can be calculated.Usually this error wiH be negligible becausethe potassium concentration in potable wateris low and also because the calculation factor,
6.5.4 Preparation of Calibration Curves
Aspirate the blank and calibration solutionsand aspirate distilled water in between. Carryout the measurements using an air-acetylene( oxidizing) flame. The wavelength and working
6.4.6 Standard Potassium Solution
Take appropriate aliquots of the stock potassium solution (4.5.2) in a series of 100 mlvolumetric flasks to give a range of standardsolutions in the working range. Add 10 ml ofsodium chloride solution ( 6....2 ) and dilute to100 ml to have about 20001£1/1 of sodium inthe working solution.
6•.t ReageDts
6.4.1 POlalslum Chloride Solution
Dissolve 40 g of potassium chloride in distilledwater and make up to 1 litre.
6.4.2 Sodium Chloride Solution
Dissolve 50 g of sodium chloride in distilledwater and make up to 1 litre.
6•.t.3 Stock Sodium Solution - See 5.4.1.
6.4.4 Stock Potassium Solution - See 5.4.1.
6•.t.5 Standard Sodium Solution
Take appropriate aliquots of the stock sodiumsolution ( 5.4.1 ) in a series of 100 ml volumetricflasks to give a range of standard solutions inthe working range. Add 10 ml of potassiumchloride solution ( 6....1 ) and dilute to 100mlto have about 2 000 p,g/I of potassium to suppress ionization while working in air-acetyleneflame.
'.5 Procedure
6.S.1 Preparation ofSample Solution - See 5.5.1.
6.5.2 Preparation of Test Solutions
Take 10 ml of the sample in a 100 volumetricflask. Add 10 ml of potassium chloride solution( 6.4.1) if sodium is to be determined and10 ml of sodium chloride solution (6.4.2) ifpotassium is to be determined. Make up to themark using distilled water.
6.5.3 Preparation of Blank Solution
Prepare appropriate blank solutions as in 6.4.5,6.4.6 and 6.5.1 using the sante reagents and samevolume of distilled water instead of the sodium( or potassium) solutions or the sample.
A x 14-95- ml of sample
0-014 9S,'Cor converting mass of sodium is verysmall. Upon evaporation of the sample, silicamay become partially dehydrated and precipitate out. Except in extreme cases, the errorcaused by silica will be negligible due to thefollowing reasons:
a) the precipitation of silica is not complete;b) some of the dehydrated silica adheres
stongly to the glass surface of the beakerand is not transferred to the crucible tobe weighed with the sodium salt;
c) the high ratio of mass of the triple saltto that of sodium and the slight increasein the mass of precipitate due to precipitated silica has a relatively small effecton the calculated sodium concentration.A method for compensation of errorscaused by precipitation of uranyl phosphate and silica is described in theprocedure.
7.3 Apparatus
7.3.1 Beakers - 20-ml borosilicate.
7.3.2 Fritted Glass Crucible - 30-ml borosilicateof medium porosilicate of medium porosity: orporous porcelain crucibles.
7.3.3 Vacuum pump or aspirator, with manifoldand individual petcocks,
7.4 Reageets
7.4.1 Zinc Uranyl Acetate Reagent
Mix 2-7 ml of glacial concentrated acetic acidwith 100 ml distilled water. Add 10 g uranylacetate dihydrate, [ DOl ( C.HaO, ). 2H 10] and30 g of zinc acetate dihydrate [ Zn ( C,HaO. ),2H.0] and warm to dissolve. On cooling, add2 to 3 mg of sodium chloride, let stand for 24hours more, and filter off the precipitate ofsodium zinc uranyl acetate, thus leaving thereagent saturated with the triple salt, Store ina pyrex bottle.
7.4.1 Ethyl Alcohol Wash Solution
Saturate 95 percent ethyl alcohol with puresodium zinc uranyl acetate and decant or filterthe solution just before use. Prepare the sodium zinc uranyl acetate by adding 25 ml zincuranyl acetate reagent to 2 ":11 sodium chloridesolution ( 10 mg NaCl), stir and collect theprecipitate in a s.intered glass cruci~le a~dwash three times With concentrated acetic acidand finally three times with diethyl ether.
7.4.3 Diethy/ Ether
7.5 ProcedureIf necessary, remove any suspended .matter fromthe potable water sample by filtration. Select
5
IS 3025 ( Part ~5 ) : 1993
a sample volume containing less than 8 mg ofsodium and less than 2S mg of potassium.Pipette the clear sample into 120 or SO-mlpyrex beaker and evaporate to dryness on asteam or hot water bath. Cool the residue toroom temperature, add 1·0 ml distilled water,rub with a stirring rod. If the residue fails todissolve, add more I·O-m) increments of distilled water to dissolve it. Ignore a featheryturbidity of calcium sulphate because of itssubsequent solubility in the zinc uranyl acetatereagent.
Treat with zinc uranyl acetate reagent in theratio of 10 ml reagent for each 10 ml incrementof distilled water required to dissolve theresidue. Mix, cover the beaker and let standfor I h. Stir periodically to prevent the formation of a supersaturated solution. Collect theprecipitate under suction in a weighed mediumporosity sintercd glass crucible. Substitute aporous-bottomed porcelain filtering crucible ifdesired. Drain the filter as dryas possible undersuction. Wash the beaker, crucible, and precipitate five to eight times with 2 ml portionsof zinc uranyl acetate reagent. Drain thecrucible completely after the last wash toremove traces of the zinc uranyl acetatereagent. Wash five times with 2-ml portions ofethyl alcohol wash solution. Conclude thewashing with three small portions of diethylether.
Continue suction for a few minutes until thediethyl ether is dry. Wipe the outside and innerbottom ring of the crucible with a cloth if saltshave crystallized there. Transfer the crucibleto the balance and weigh after 10 to 15 min andagain 10 min latter to check on the constancy ofthe mass. Return the crucible to the suctionapparatus and dissolve the sodium zinc uranylacetate by passing 100 ml warm distilled waterin small portions through the filter. Dry thecrucible with ethyl alcohol wash 501uI00 anddiethyl ether, as previously directed, andreweigh. The difference in the mass before andafter the distilled water treatment representsthe mass of the sodium zinc uranyl acetants.
chloride ( 241 mgtl Cl), nitrite (0·25 mgtl N),nitrate ( 1·1 mgtl N ), sulphate ( 259 mg/ I S04)and 42·S mg/l total alkalinity (contributed byNaHCOa ) was analyzed ill four laboratories bythe gravimetric method with a relative standarddeviation of 11·3 percent and a relative errorof 0·5 percent.
Potassium is determined calorimetrically byprecipitating it with sodium cobalt nitrite,oxidizing the dipotassium sodium cobalt nitratewith standard potassium dichromate solutionin the presence of sulphuric acid measuring theexcess dichromate calorimetrically.
8.2 Interference
Ammonium ion interferes and should not bepresent. Silica causes no difficulty unless asilica gel is formed" either during evaporationor when the sample becomes acidic upon addition of the reagent. If this occurs, as evidencedby turbidity in the final coloured solution,filtration will be necessary. Other substancesnormally present in water do not interfere.
8.3 Minimum Detectable ConcentratioD
This method can detect 0·5 mg potassium whena IS-em light path is used. This represents apotassium concentration of 5 mg/l when a100-ml sample is taken for analysis.
8.4 Apparatus
8.4.1 Colorimetric Equipment
One of the following is required:
a) Spectrophotometer, for use at l12S nm,providing a light path of I em or longer.
h) Filter photometer, providing a light pathof I ern or Nessler tubes, matches, lOO-mltall from.
8.4.2 Centrifuge8.4.3 Centrifuge Tubes - 25 rnl,
8.4.4 Small-diameter stirring rods, 2 to 3 rom,to stir the precipitate in the centrifuge tube.
8.5 Reagents
8.S.1 Nitric Acid -- concentrated IN.
8.5.2 Trisodium Cobalt Nitrite Solution
8.5.3 Nitric Acid - O·Oi N.
Dilute 10 ml of 1 N nitric acid in 11 withdistilled water.
6
8.5.4 Standard Potassium DicIJromate-O·IOOON.Dissolve 4·904 g anhydrous potassium dichromate in distilled water, and make up to I 000 mi.This solution is stable for long period.
8.5.5 Sulphuric Acid - Concentrated.
8.5.6 Stock Potassium Solution
Dissolve 1·907 g potassium chloride dried at110°C and dilute to 1 000 ml with deionizeddistilled water. 1 ml = 1·00 mg potassium,
8.5.7 Standard Potassium Solution
Dilute 1·00 ml intermediate potassium solutionwith deionized distilled water to 100 ml; 1-00ml = 10·0 p.g potassium. Use this solution forpreparing the calibration curve in the potassiumrange of 0·1 to 1-0 mg/l.
8.6 Procedure
8.6.1 Sample Volume
If the sample contains from 100 to 700 lng/Ipotassium, use a 10-ml portion. If it containsless, concentrate a large portion by evaporationto about 5 ml, transfer to a 25 ml centrifugetube, and make up to 10 mi.
8.6.2 Colour Production
At room temperature, add with mixing, 1 rnl of1 N nitric acid and 5 ml trisodium cobalt nitritesolution. Let stand for 2 h. In as much asthe composition of the precipitate depends onthe time allowed for precipitation as well ason the temperature; keep the time constants(± IS min) for all samples. A variation of 10°Cin either direction will give an error of 2 percentcentrifuge for JO minutes. Decant and washthe precipitate with IS ml of 0'01 N nitric acid;using a small diameter stirring rode mix toensure complete contact between precipitateand wash solution; centrifuge again, decant.and add with mixing 10 ml standard potassiumdichromate solution and 5 In} concentratedsulphuric acid. Cool to room temperature.Make up to 100 ml with distilled water. Filterif, the solution is turbid.
8.6.3 Preparation of Standards
Pipette 1, 2, 3, 4, S, 6 and 7 ml standard potassium solution into 2S-ml centrifuge tubes; diluteeach to 10 ml and produce standards containing1·0 to 7·0 mg potassium.
8.6.4 CO/OIlT MeasurementMeasure the colour either photometrically orvisually.8.6.4.1 Photometric measurementUse the longest light path available with theinstrument to measure the absorbance or
transmittance of the sample and standards by aspectrophotometer with 2 em light path. Preparethe calibration graph in the range of 2 to 7 mgpotassium. Por a filter photometer with aIS-ml light path, prepare the calibration curvein the range of 0-5 to 7 mg potassium.
8.6.4.2 V1SUQI Colour Comparison
Compare the sample against the standards inthe range from 2 to 7 mg potassium. Protectfrom dust and strong light to preserve stability
of the solutions for at least one week.
8.7 CalcalatioBPotassium ( K ), (mg of potassium )mg/l, percent = Ifrom calibration J
curvel sample in rnl x 1000
8.8 PreclsioD and AccuracyBoth visual and spectrophotometric readingswith a 2 em light path can be made with anestimated accuracy of ± O· 5 mg potassium.
7
IS 3025 ( Part 45 ) : 1"3
National Environmental Engineerinl Research Institute( CSIR ), Nalpur
Ministry of Rural Development
Directorate General Factory Advice Service & Labour Institutes.Bombay
National Thermal Power Corporation Ltd. New Delhi
Shriram Institute for Industrial Research, Delhi
Indian Petrochemicals Corporation Ltd, Vadodara
Indian Council of Agricultural Research, New DelhiNational Council for Cement & Building Materials, New Delhi
Central Scientific Instruments Organiza tion ( CSIR ), Chandigarh
DR K. R. RANOANA...IIAN ( Alternate toShri N. S. Tiwana)
ADVISER ( PRE )ADDL ADVISER ( PRE ) ( ..jltern(Jt~ )
DR A. L. AOOARWAL
DR T. CHAKRABARn ( Alternate)DRA. ALAM
SHRI S. C. AHLUWALIASURI A. D. AONIHOTRI ( Alternate)
DR S. K. AWASTHISHRI D. C. BHATT ( ~/te,nale )
SRRI R. K. BANERJEESaal p. K MAIR ( Alternate )
SRRI B. BASUDR S. MUKHERJEE ( Alternate)
SHRIV.S.BHATNAGARDR M. S. N. SRINIVAS ( Alternate )
SRRI S. CHAKRAVORTI
DR M. H. FULEKAR ( Alternat~)
SHRI M. OOPALXRISHNADR S. RAHUT ( Anemate )
SHaI S. GOURISHANKARSRRI S. BALAOURUNATHAN ( Alternate)
DR HARISH CHANDRA
SHRI B. K. JAINDR ( MS ) B. SWAMINATHAN ( Alternate)
SHRI S. K. JAINSHRI R. K. MALHOTRA ( Alternate)
SHRI P. M. KULKARNIDR A. K. WAGLE ( Alternate)SHRI A. LABIRI
SHRI B. B. DAVE ( Atternate )SRRI M. K. Looa
SRRI D. N. P. SINGH ( Alternat )DR W. MADHA VAKRISHNA
SaRI S. RAJAMANI ( Alternate)Sml S. K. MAIKA
SHRI A. SAHA ( Alternate )DR P. K. MATHUR
DR P. M. MODAICPROF H. Vf.ERAMANI ( Alternate)
SHRI K. P. NYATISHRI L. PANEERSELvAJ,f ( Alternate )
PROF B. PADMANABHAMVRTHY
DR T. S. PATEL
SHRI C. V. RAIYANI ( Altemat« )OR V. V. RAO
DR M. ATCHAYYA ( Alternate)
National Test House, Calcutta
Bharat Heavy Electricals Ltd, Hyderabad
Industrial Toxicology Research Centre ( CSIR ), LucknowThe Fertilizer Association of India. New Delhi
Indian Oil Corporation Ltd ( R&D Centre ), Faridubad
Thermax Ltd, Pune
Hindustan Lever Ltd, Bornbav
Projects & Development India Ltd, Sindri
Central Leather Research Institute ( CSIR ), MadJas
Flakt India Ltd, Calcutta
Bhabha Atomic Research Centre ( IGCAR). Kalpakkam (TN)Indian Institute of Technology, Bombay
National Productivity Council, New Delhi
Jawaharlal Nehru University, New DelhiNational Institute of Occupational Health ( ICMR ),
Ahmedabad
Dharmsi Morarji Chemical Co, Ltd, Bombay
SaRI P. S. RAMANATHAN
SHRI D. N. V. RAODR N. N. SHARMA (Alternate)
REPRESENTATIVE
SIIRJ S. A. ROO!SHaI V. S. MAHAJAN ( Alternate)
SaRI P. R. SAMADDARSRRI p. K. SIN ( Alternate )
DR K. D. SHARMASHRI C. D. BANKER ( Alternate)
SHRI S. C. SHARMASHRI R. N. GUPTA ( Alternate)SRRI M. SUBDA RAO
DR T. CHANDINI ( Alternate)SURI SURENDER KUMAR
SRRI R. PARTHASARTHY ( Alternate)SUPERINTENDINO ENGINEER
EXECUTIVE ENGINEER ( Alternate)SURr J. M. TULI
SHRI S. N. C'HAKRABARTI ( Alternate )DR R. K. SINGH,
Director ( Chem )
IS 3025 ( Part 45 ) : 1993
Pesticides Association of India, New Delhi
Tata Chemicals Ltd. Bombay
National Malaria Eradication Programme ( DOHS ), DelhiMunicipal Corporation of Greater Bombay
Central Mechanical Ensg Research Institute ( CSIR ), Durgapur
Direetora te General of Technical Development, New Delhi
India Meteorological Department, New Delhi
Ministry of Environment & Forests
Indian Chemical Manufacturers Association. New Delhi
Panchayat Raj Department, Government of Andhra Pradesh,Hyderabad
Engineers India Ltd, New Delhi
Director General, DIS ( Ex-officio Member)
Member SecretarySHRI T. RANOASAMY
Joint Director ( Chern ), DIS
Water Environment Subcommittee, CHD 012: 01Convener
DR Y. P. KAICAR
MembersSHRIS.B.C.AoARWALA
SHRt A. K. GUPTA ( Alternate)SHRI A. BASU
SHRl A. K. JINDAL ( Alternate)DR E. K. JAYANARAYANAN
SHR) K. K. M ITTU ( Alternate):)HRI S. ISLAMSHRl F. LAL KANSAL
SHR) B. R. BANSAL ( Alternate)PROF K. J. NATH
PROF A. K. AOHYA ( Alternate)DR S. R. PANDE
DR S. R. JOSHI ( Alternate)DR p. M. PHIRXE
DR M. V. NANOTI ( Ahernat« )SHRI S. PRAKASH
SURI S. S. RAMRAKHYANI ( Alternate)SURI D. N. V. RAO
DR N. N. SHARMA ( Alternate)SURI R. V. RAO
SHRt p. K. SHARMA ( Alternate)REPRESENTATIVEREPRESENTATJVEREPRESENTATIVEDR R. SENGUPTA
DR R. C. TRIVEDI ( Alternate)DR R. SETH
DR S. RATAN ( Alternate)SUPERINTENDING ENGINEER
EXECUTIVE ENOINEER ( Alternate)SHRIS.R.TAMTA
SHRI K. RAJAOOPALAN ( Altemate )DR p. N. VISWANATHAN
Ministry of Environment &. Forelta
Bharat Heavy Electricals Ltd, Hyderabad
Thermax Ltd, Pune
Mohan Meakin Ltd, Mohan Nalar
Cen tral Pulp and Paper Research Institute, SaharanpurPunjab Pollution Control Board, Patiala
All India Institute of Hygiene &. Public Health, Calcutta
National Environment Engineering Research Institute ( CSIR ),Nagpur
National Environment Engineering Research Institute (CSIR).Nagpur
Delhi Water Supply &t Sewage Disposal Undertaking, New Delhi
Tata Chemicals Ltd, Bombay
Central Water Commission, Ne" Delhi
Ministry of Rural DevelopmentShriram Institute for Industrial Research, DelhiU. p. Jal Nigam, LucknowCentral Pollution Control Board, Delhi
Banaras Hindu University, Varanasi
Panchayat Raj Department, Goverment of Andhra Pradesh,Hydcrabad
Central Ground Water Board. New Delhi
Industrial Toxicology Research Centre ( CSIR ). Lucknow
9
Bureau of Indian Standards
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This Indian Standard has been developed from Doc: No. tHO 012 (0050).
Amendments Issued Since Publication
Amend No. Date of Issue
BUREAU OF INDIAN STANDARDS
Text Affected
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