OMB Meeting Book - Jan. 11, 2018

2016.03 (Nov. 2017) - Chlor-02/04 Final Action Review FOR ERP USE ONLY DO NOT DISTRIBUTE

Put the wash solution (D. f) in the washing position if an auto sampler is used. Ensure that the volume of wash solution is adequate. Under continuous stirring and without touching the electrode, titrate the sample solution automatically with silver nitrate solution (C. g or D. a), up to the end potential, The consumption of silver nitrate solution (C. g or D. a) should be recorded automatically and can be read from the titrator software, or documented in the titrator operating records. For manual titration using a burette, add standardized silver nitrate solution (C. g or D. a), until the end potential has nearly been met. Continue to titrate slowly until the end point is met as observed on the meter with two small (about 0,05 ml) additions of silver nitrate solution.

(c). Determination of very low amounts of chloride

When determining low chloride (e.g. <10-20 mg/ 100g) concentrations, like in desalted whey powder, for greater precision a standardized 0,025 mol/l AgNO 3 (D. g) solution should be used for the titration,

(d). Blank test

To determine the reagent background content of chloride, perform a blank test using reagents substituting water (C. a) for the sample portion, The titrant consumption of the blank test obtained at the endpoint shall be less than 0.05 ml while using the standardized silver nitrate solution (D. a) and 0.2 ml when using the 0.025 mol/l standardized silver nitrate solution (D. g). Otherwise check the reagents and water involved in the procedures, and perform the blank test again until the criteria is achieved.

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