Packaging and storage
Preserve in tight,light-resistant containers.
Labeling
The label states that the product is Water-Soluble Vitamins with Minerals Capsules.The label also states the quantity of each vitamin and mineral in terms of metric units per dosage unit and where necessary the chemical form in which a vitamin is present and also states the salt form of the mineral used as the source of each element.Where more than one Assaymethod is given for a particular vitamin or mineral,the labeling states with which Assaymethod the product complies only if Method 1is not used.
Microbial enumeration á2021ñ
The total aerobic microbial count does not exceed 3000cfu per g,and the combined molds and yeasts count does not exceed 300cfu per g.Capsules also meet the requirements of the tests for absence of
Salmonellaspecies,
Escherichia coli,and
Staphylococcus aureus.
Weight variation á2091ñ:
meet the requirements.
NOTEIn the following Assays,where more than one Assaymethod is given for an individual ingredient,the requirements may be met by following any one of the specified methods,the method used being stated in the labeling only if Method 1is not used.
Assay for ascorbic acid,Method 1
Accurately weigh not fewer than 20Capsules in a tared weighing bottle.Using a sharp blade if necessary,carefully cut open the Capsules,without the loss of shell material,and transfer the contents to a 100-mLbeaker.Remove any contents adhering to the empty shells by washing if necessary with several portions of ether.Discard the washings,and dry the Capsule shells with the aid of a current of dry air until the odor of ether is no longer perceptible.Weigh the empty Capsule shells in the tared weighing bottle,and calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 100mg of ascorbic acid,to a 200-mLvolumetric flask,and proceed as directed in the
Assay for ascorbic acid,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,beginning with add about 75mLof metaphosphoric-acetic acids TSand calculating the content of ascorbic acid in each Capsule.
Assay for calcium ascorbate,Method 1
Proceed as directed in the Assay for ascorbic acid,Method 1.
Assay for sodium ascorbate,Method 1
Proceed as directed in the Assay for ascorbic acid,Method 1.
Assay for biotin,Method 1
Proceed as directed in the
Assay for biotin,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the
Assay for ascorbic acid,
Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 1mg of biotin,to a 200-mLvolumetric flask.Add 3mLof dimethyl sulfoxide,and swirl to wet the contents.Place the flask in a water bath at 60

to 70

for 5minutes.Sonicate for 5minutes,dilute with water to volume,mix,and filter.
Assay for biotin,Method 2
Proceed as directed in the
Assay for biotin,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the
Assay for ascorbic acid,
Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 100µg of biotin,to a 200-mLvolumetric flask,add 3mLof 50percent alcohol,and swirl to wet the contents.Heat the flask in a water bath at 60

to 70

for 5minutes.Sonicate for 5minutes,dilute with water to volume,mix,and filter.Dilute an accurately measured volume of the filtrate quantitatively,and stepwise if necessary,with diluted alcohol to obtain a solution having a concentration of about 0.1ng per mL.
Assay for cyanocobalamin,Method 1
Proceed as directed in the
Assay for cyanocobalamin,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the Assay for ascorbic acid,Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 100µg of cyanocobalamin,to a 250-mLflask.Quantitatively add 100.0mLof water,and carefully extract for 2minutes.Filter about 10mLof the extract,and use the clear solution.
Assay for cyanocobalamin,Method 2
Proceed as directed in the
Assay for cyanocobalamin,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the
Assay for ascorbic acid,
Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 1.0µg of cyanocobalamin,to an appropriate vessel containing,for each g of Capsule contents taken,25mLof an aqueous extracting solution prepared just prior to use to contain,in each 100mL,1.29g of dibasic sodium phosphate,1.1g of anhydrous citric acid,and 1.0g of sodium metabisulfite.Autoclave the mixture at 121

for 10minutes.Allow any undissolved particles of the extract to settle,and filter or centrifuge if necessary.Dilute an aliquot of the clear solution with water to obtain a final solution containing vitamin B
12activity approximately equivalent to that of the
Standard preparation.
Assay for folic acid,Method 1
Proceed as directed in the
Assay for folic acid,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the Assay for ascorbic acid,Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 0.4mg of folic acid,to a 50-mLcentrifuge tube.Add 25.0mLof Internal standard preparation,insert a stopper,shake by mechanical means for 10minutes,and centrifuge.Filter a portion of the clear supernatant,and use the filtrate.
Assay for folic acid,Method 2
Proceed as directed in the
Assay for folic acid,
Method 2under
Water-Soluble Vitamins Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed for
Assay preparationin the
Assay for ascorbic acid,
Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 0.3mg of folic acid,to a stoppered 125-mLflask.Add 10.0mLof a mixture of methanol and glacial acetic acid (9:1)and 30mLof a mixture of methanol and ethylene glycol (1:1),insert the stopper,shake for 15minutes in a water bath maintained at 60

,and cool.Filter,discarding the first few mLof the filtrate.
Assay for calcium pantothenate,Method 1
Proceed as directed in the
Assay for calcium pantothenate,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the Assay for ascorbic acid,Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 15mg of calcium pantothenate,to a centrifuge tube.Transfer 25.0mLof the Internal standard preparationto the centrifuge tube,and shake vigorously for 10minutes.Centrifuge,filter,and use the clear filtrate.
Assay for calcium pantothenate,Method 2
Proceed as directed in the
Assay for calcium pantothenate,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the Assay for ascorbic acid,Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 50mg of calcium pantothenate,to a 1000-mLvolumetric flask containing 500mLof water.Add 10mLof 0.2Nacetic acid and 100mLof sodium acetate solution (1in 60),dilute with water to volume,and filter.Dilute an accurately measured volume of this solution quantitatively,and stepwise if necessary,to obtain a solution having about the same concentration as that of the Standard preparation.
Assay for calcium pantothenate,Method 3
Proceed as directed in the
Assay for calcium pantothenate,
Method 3under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the Assay for ascorbic acid,Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 10mg of calcium pantothenate,to a 250-mLvolumetric flask,add 10mLof methanol,and swirl the flask to disperse the Capsule contents.Dilute with water to volume,mix,and filter.
Assay for niacin or niacinamide,pyridoxine hydrochloride,riboflavin,and thiamine,Method 1
Proceed as directed in the
Assay for niacin or niacinamide,
pyridoxine hydrochloride,
riboflavin,
and thiamine,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the
Assay for ascorbic acid,
Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 10mg of niacinamide and 2.5mg each of pyridoxine hydrochloride,riboflavin,and thiamine hydrochloride,to a 50-mLcentrifuge tube.Add 25.0mLof
Diluting solution,and mix,using a vortex mixer,for 30seconds to completely suspend the powder.Immerse the centrifuge tube in a hot water bath maintained at 65

to 70

,heat for 5minutes,and mix,using a vortex mixer,for 30seconds.Return the tube to the hot water bath,heat for another 5minutes,and mix,using a vortex mixer,for 30seconds.Filter a portion of the solution,cool to room temperature,and use the clear filtrate.
[NOTEUse the filtrate within 3hours after filtration.
]
Assay for niacin,Method 2
Proceed as directed in the
Assay for niacin,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
[NOTEThis preparation is suitable for the determination of niacin or niacinamide,pyridoxine hydrochloride,and riboflavin,when present in the formulation.
]Accurately weigh not fewer than 20Capsules in a tared weighing bottle.Using a sharp blade if necessary,carefully open the Capsules,without loss of shell material,and transfer the contents to a beaker.Remove any contents adhering to the shells by washing with several portions of ether.Discard the washings,and dry the Capsule shells with the aid of a current of dry air.Weigh the empty Capsule shells in the tared weighing bottle,and calculate the net weight of the Capsule contents.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 2mg of riboflavin,to a 250-mLvolumetric flask.If riboflavin is not present in the formulation,use a portion equivalent to about 2mg of pyridoxine.If pyridoxine is not present in the formulation,use a portion equivalent to about 20mg of niacin or niacinamide.Add 100.0mLof
Extraction solvent,and mix for 20minutes,using a wrist-action shaker.Immerse the flask in a water bath maintained at 70

to 75

,and heat for 20minutes.Mix on a vortex mixer for 30seconds,cool to room temperature,and filter.Use the clear filtrate.
Assay for niacinamide,Method 2
Proceed as directed in the
Assay for niacinamide,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Prepare as directed for Assay preparationin the Assay for niacin,Method 2.
Assay for pyridoxine hydrochloride,Method 2
Proceed as directed in the
Assay for pyridoxine hydrochloride,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Prepare as directed for Assay preparation in the Assay for niacin,Method 2.
Assay for riboflavin,Method 2
Proceed as directed in the
Assay for riboflavin,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Prepare as directed for Assay preparationin the Assay for niacin,Method 2.
Assay for thiamine,Method 2
Proceed as directed in the
Assay for thiamine,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the Assay for ascorbic acid,Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the contents,equivalent to about 2mg of thiamine,to a 250-mLvolumetric flask.Add 100.0mLof 0.2Nhydrochloric acid,shake for 15minutes with a wrist-action shaker,and heat to boiling for 30minutes.Cool to room temperature,filter,and use the clear filtrate.
Assay for niacin or niacinamide,pyridoxine hydrochloride,riboflavin,and thiamine,Method 3
Proceed as directed in the
Assay for niacin or niacinamide,
pyridoxine hydrochloride,
riboflavin,
and thiamine,
Method 3under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Proceed as directed in the
Assay for ascorbic acid,
Method 1,through calculate the average net weight per Capsule.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 7.5mg of niacin or niacinamide,1.2mg of pyridoxine hydrochloride,0.4mg of riboflavin,and 1.2mg of thiamine hydrochloride,to a stoppered 125-mLflask.Add 10.0mLof a mixture of methanol and glacial acetic acid (9:1)and 30.0mLof a mixture of methanol and ethylene glycol (1:1).Insert the stopper,shake for 15minutes in a water bath maintained at 60

,and cool.Filter,discarding the first few mLof the filtrate.
NOTECommercially available atomic absorption standard solutions for the minerals,where applicable,may be used where preparation of a standard stock solution is described in the following Assays.Use deionized water where water is specified.Where atomic absorption spectrophotometry is specified in the Assay,the Standard preparationsand the Assay preparationmay be diluted quantitatively with the solvent specified,if necessary,to yield solutions of suitable concentrations adaptable to the linear or working range of the instrument.
Assay for calcium
Proceed as directed in the
Assay for calciumunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Dilute 100mLof polysorbate 80with alcohol to 1000mL.
Assay preparation
Transfer 5Capsules to a 100-mLvolumetric flask.[NOTEFor hard gelatin Capsules,accurately weigh not fewer than 20Capsules.Using a sharp blade if necessary,carefully open the Capsules,without loss of shell material,and transfer the contents to a suitable container.Remove any contents adhering to the empty shells by washing with several portions of ether.Discard the washings,and allow the Capsule shells to dry.Weigh the empty Capsule shells,calculate the net weight of the Capsule contents,and transfer an accurately weighed portion of the Capsule contents,equivalent to about 5Capsules,to a 100-mLvolumetric flask.]Add about 15mLof water,10mLof 6Nhydrochloric acid,and about 1mLof Polysorbate 80solutionto the flask,and heat on a hot plate or steam bath,with intermittent swirling,until the Capsules are completely disintegrated or the contents are dissolved.Boil gently for an additional 15minutes.Cool,dilute with water to volume,and filter,discarding the first 5mLof the filtrate.Dilute this solution quantitatively,and stepwise if necessary,with 0.125Nhydrochloric acid to obtain a solution having a known concentration of about 2µg of calcium per mL,adding 1mLof Lanthanum chloride solutionper 100mLof the final volume.
Assay for chromium
Proceed as directed in the
Assay for chromiumunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Prepare as directed in the Assay for calcium.
Assay preparation
Proceed as directed for Assay preparationin the Assay for calcium,except to prepare the Assay preparationto contain about 1µg of chromium per mLand to omit the use of the Lanthanum chloride solution.
Assay for copper
Proceed as directed in the
Assay for copperunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Prepare as directed in the Assay for calcium.
Assay preparation
Proceed as directed for Assay preparationin the Assay for calcium,except to prepare the Assay preparationto contain about 2µg of copper per mLand to omit the use of the Lanthanum chloride solution.
Assay for fluoride,Method 1
Proceed as directed in the
Assay for fluoride,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Remove the contents of a counted number of Capsules by cutting open the Capsules,using a sharp blade if necessary.Mix,and determine the weight of the contents.Transfer an accurately weighed quantity of the contents,equivalent to about 200µg of fluoride,to a 100-mLvolumetric flask.Add 10.0mLof 1Nhydrochloric acid,25.0mLof 3M Sodium acetate solution,and 25.0mLof Sodium citrate solution,dilute with water to volume,and mix.
Assay for fluoride,Method 2
Proceed as directed in the
Assay for fluoride,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Accurately weigh not fewer than 20Capsules in a tared weighing bottle.Using a sharp blade if necessary,carefully open the Capsules,without loss of shell material,and transfer the contents to a 100-mLcontainer.If necessary,remove any contents adhering to the empty shells by washing with several portions of ether.Discard the washings,and dry the Capsule shells with the aid of a current of dry air.Weigh the empty Capsule shells in the tared weighing bottle,and calculate the net weight of the Capsule contents.Transfer an accurately weighed portion of the Capsule contents,equivalent to about 1mg of fluoride,to a 100-mLvolumetric flask.Proceed as directed for
Assay preparationin the
Assay for fluoride,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,beginning with add 15mLof water.
Assay for iodide,Method 1
Bromine water
To about 20mLof bromine in a glass-stoppered bottle,add 100mLof water.Insert the stopper into the bottle,and shake.Allow to stand for 30minutes,and use the supernatant layer.
Procedure
Remove the contents of a counted number of Capsules by cutting open the Capsules,using a sharp blade if necessary.Mix,and determine the weight of the contents.Transfer an accurately weighed quantity of the contents,equivalent to about 3mg of iodine,to a nickel crucible.Proceed as directed for
Procedurein the
Assay for iodide,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,beginning with Add 5g of sodium carbonate.
Assay for iron
Proceed as directed in the
Assay for ironunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Prepare as directed in the Assay for calcium.
Assay preparation
Proceed as directed for Assay preparationin the Assay for calcium,except to prepare the Assay preparationto contain about 5µg of iron per mLand to omit the use of the Lanthanum chloride solution.
Assay for magnesium
Proceed as directed in the
Assay for magnesiumunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Prepare as directed in the Assay for calcium.
Assay preparation
Proceed as directed for Assay preparationin the Assay for calcium,except to prepare the Assay preparationto contain about 0.4µg of magnesium per mL.
Assay for manganese
Proceed as directed in the
Assay for manganeseunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Prepare as directed in the Assay for calcium.
Assay preparation
Proceed as directed for Assay preparationin the Assay for calcium,except to prepare the Assay preparationto contain about 1µg of manganese per mLand to omit the use of the Lanthanum chloride solution.
Assay for molybdenum,Method 1
Proceed as directed in the
Assay for molybdenum,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Prepare as directed in the Assay for calcium.
Assay preparation
Proceed as directed for Assay preparationin the Assay for calcium,except to take a number of Capsules or a portion of Capsule contents equivalent to about 1000µg of molybdenum and to make appropriate dilutions to obtain a final concentration of about 10µg of molybdenum per mL,omitting the addition of the Lanthanum chloride solution.
Assay for molybdenum,Method 2
Proceed as directed in the
Assay for molybdenum,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Procedure.
Procedure
Remove the contents of a counted number of Capsules by cutting open the Capsules,using a sharp blade if necessary.Mix,and determine the weight of the contents.Transfer an accurately weighed quantity of the Capsule contents,equivalent to about 40µg of molybdenum,to a 200-mLbeaker,marked
I.Proceed as directed for
Procedurein the
Assay for molybdenum,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,beginning with To another 200-mLbeaker,except to read Capsules in place of Tablets.
Assay for phosphorus
Proceed as directed in the
Assay for phosphorusunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Remove the contents of a counted number of Capsules by cutting open the Capsules,using a sharp blade if necessary.Mix,and determine the weight of the contents.Transfer an accurately weighed quantity of the Capsule contents,equivalent to about 100mg of phosphorus,to a suitable flask.Proceed as directed for
Assay preparationin the
Assay for phosphorusunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,beginning with add 25mLof nitric acid.
Assay for potassium
Proceed as directed in the
Assay for potassiumunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Prepare as directed in the Assay for calcium.
Assay preparation
Proceed as directed for Assay preparationin the Assay for calcium,except to prepare the Assay preparationto contain about 1µg of potassium per mLand to omit the use of the Lanthanum chloride solution.
Assay for selenium,Method 1
Proceed as directed in the
Assay for selenium,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Remove the contents of a counted number of Capsules by cutting open the Capsules,using a sharp blade if necessary.Mix,and determine the weight of the contents.Transfer an accurately weighed quantity of the Capsule contents,equivalent to about 1000µg of selenium,to a suitable flask.Proceed as directed for
Assay preparationin the
Assay for selenium,
Method 1under
Oil-and Water-Soluble Vitamins with Minerals Tablets,beginning with and add about 12mLof nitric acid.
Assay for selenium,Method 2
Proceed as directed in the
Assay for selenium,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Assay preparation.
Assay preparation
Remove the contents of a counted number of Capsules by cutting open the Capsules,using a sharp blade if necessary.Mix,and determine the weight of the contents.Transfer an accurately weighed quantity of the Capsule contents,equivalent to about 20µg of selenium,to a suitable flask.Proceed as directed for
Assay preparationin the
Assay for selenium,
Method 2under
Oil-and Water-Soluble Vitamins with Minerals Tablets,beginning with Add 10mLof nitric acid.
Assay for zinc
Proceed as directed in the
Assay for zincunder
Oil-and Water-Soluble Vitamins with Minerals Tablets,except to read Capsules in place of Tablets and to use the following
Polysorbate 80solutionand
Assay preparation.
Polysorbate 80solution
Prepare as directed in the Assay for calcium.
Assay preparation
Proceed as directed for Assay preparationin the Assay for calcium,except to prepare the Assay preparationto contain about 2µg of zinc per mLand to omit the use of the Lanthanum chloride solution.