GB 5009.234-2016 English PDF (GB5009.234-2016)

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GB 5009.234-2016: Method for analysis of hygienic standard of soybean sauce
GB 5009.234-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard -
Determination of Ammonium Salt in Foods
ISSUED ON: AUGUST 31, 2016
IMPLEMENTED ON: MARCH 01, 2017
Issued by: National Health and Family Planning Commission of the PRC
Table of Contents
Foreword ...3
1 Scope ...4
2 Principle ...4
3 Reagents and materials ...4
4 Instruments and apparatuses ...5
5 Analysis steps ...5
6 Description of the analysis result ...5
7 Precision ...6
8 Others ...6
National Food Safety Standard -
Determination of Ammonium Salt in Foods
1 Scope
This Standard specifies the method for determination of ammonium salt in soy sauce.
This Standard applies to the determination of ammonium salt in soy sauce.
2 Principle
Heat and distill the sample in the alkaline solution to free the ammonia, which is
absorbed by the boric acid solution; then use hydrochloric acid standard solution to
titrate and calculate the content.
3 Reagents and materials
3.1 Reagents
Unless otherwise specified, all the reagents in this method are analytical reagents, the
water is grade-1 water that is specified by GB/T 6682.
3.1.1 Magnesium oxide (MgO).
3.1.2 Boric acid (H3BO3).
3.1.3 Methyl red (C15H15N3O2).
3.1.4 Bromocresol green (C15H14Br4O5S).
3.1.5 Ethanol (C2H5OH).
3.2 Preparation of reagents
3.2.1 Boric acid solution (20 g/L): weigh 20.0 g of boric acid; add water to dissolve;
dilute to 1 000 mL.
3.2.2 Hydrochloric acid standard titration solution [c(HCl)] = 0.100 mol/L.
3.2.3 Mixing indicator solution: 1 part of methyl red-ethanol solution (2 g/L) and 5 parts
of bromocresol green-ethanol solution (2 g/L); prepare when it is needed.