Methods to be Reviewed by OMB in 2016

(2.862.0010) equippedwith 800 Dosino (2.800.0010), 10mL dosing unit (6.3032.210) and

automatic propeller blending device or equivalent.

Reagents

(a)

Water

.-Reagent Grade.

(b)

Silver nitrate solution

.-0.1Mstandard titrant with certified concentration to 4 significant

figures. (c)

Potassium ferrocyanide trihydrate

.-Analytical reagent.

(d)

Zinc acetate dehydrate

.- Analytical reagent.

(e)

Nitric acid

.- Analytical reagent.

(f)

Ethanol

.- Analytical reagent.

(g)

Sodium chloride

.- Reference reagent.

Preparation of Solutions

(a)

Precipitating agent I

.- Dissolve 106 g potassiumferrocyanide trihydrate and bring to 1000

mL usingwater.

(b)

Precipitating agent II

.-Dissolve 220 g zinc acetate dehydrate and bring to 1000mL using

water.

(c)

Nitric acid solution

.-Add 100mL nitric acid to 300mL water and mix well.

(d)

Washing solution

.-Add 75mL ethanol to 25mL water and mix well.

(e)

Sodium chloride standard solution (NaCl SS)

.-Weigh 250mg (accurate to 0.01mg) NaCl

and dissolve inwater to total solutionweight of 25 g (accurate to 0.1mg). Mix well. Prepare

fresh before the titer check.

Sample Preparation

(a) Weigh 5 g (accurate to 0.1mg) powder sample (2 g for skim milk powder) or 20 g

(accurate to 0.1mg) liquid sample in 50mL centrifuge tube. Add 25mL 40

℃

water for powder

sample and dissolve thoroughly.

Candidates for 2016 Method of the Year