Methods to be Reviewed by OMB in 2016

AOAC Official Method 2015.07

Chloride in Infant Formula and Adult/Pediatric Nutritional Formula

Potentiometric Titration Method

First Action 2015

(Applicable for determination of chloride in all forms of infant, adult, and/or pediatric formula

including powders, ready to feed liquids, and liquid concentrates.)

Caution

Refer to Material Safety Data Sheets prior to use of chemicals. Use appropriate

personal protective equipment when performing testing.

Principle

Samples are treated with potassiumferrocyanide and zinc acetate to precipitate protein,

acidifiedwith nitric acid, and titrated using silver nitrate as titrant. The endpoint of titration is

determined by the potentiometric method on a silver titrode with silver sulfide coated electrode.

Chloride content is calculated in the sample via the titrant volume at the endpoint.

Apparatus

(a)

Analytical Balances

.-Accurate to 0.1mg and 0.01 mg.

(b)

Centrifuge

.-Tabletopwith rotor to fit 50mL conical tubes.

(c)

Centrifuge tubes

.-50mL, conical, polypropylene.

(d)

Pipette

.-10mL, grade A.

(e)

Volumetric flasks

.-50, 100, 500, and 1000 mL glass.

(f)

Graduated cylinders.-

25mL, 100mL, and 500 mL, glass.

(g)

Beaker

.-120mL, Metrohm sample beaker (6.1459.300) or equivalent.

(h)

Silver titrode

.-Metrohm Ag titrode (6.0430.100) or equivalent.

(i)

Automatic potentiometric titration system

.-Metrohm 862 Compact Titrosampler

Candidates for 2016 Method of the Year