GB 5009.233-2016 English PDF (GB5009.233-2016)

Delivery: 3 seconds. Download true-PDF + Invoice.
Get QUOTATION in 1-minute: Click GB 5009.233-2016
Historical versions: GB 5009.233-2016
Preview True-PDF (Reload/Scroll if blank)

GB 5009.233-2016: Method for analysis of hygienic standard of vinegar
GB 5009.233-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard -
Determination of Free Mineral Acid in Vinegar
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 Analysis steps ...5
5 Analysis result ...5
6 Others ...5
National Food Safety Standard -
Determination of Free Mineral Acid in Vinegar
1 Scope
This Standard specifies the method for determination of free mineral acid in vinegar.
This Standard applies to the determination of free mineral acid in vinegar
2 Principle
When there is free mineral acid (such as sulfuric acid, nitric acid, hydrochloric acid),
the concentration of hydrogen ions increases, and the color of the indicator can be
changed.
3 Reagents and materials
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 Reagents
3.1.1 Thymol blue.
3.1.2 Methyl violet (C25H30N3Cl).
3.1.3 Sodium hydroxide (NaOH).
3.1.4 Ethanol (CH3CH2OH).
3.2 Preparation of reagents
3.2.1 Sodium hydroxide solution (4 g/L): take 2 g of sodium hydroxide to dissolve in
water; add water to 500 mL.
3.2.2 Thymol blue test paper: take 0.10 g of thymol blue to dissolve in 50 mL of ethanol;
add 6 mL of sodium hydroxide solution (4 g/L); add water to 100 mL. Use the solution
to soak the filter paper; then dry it, and store for later use.
3.2.3 Methyl violet test paper: weigh 0.10 g of methyl violet to dissolve in 100 mL of
water; immerse the filter paper in this solution; take it out and dry it; store for later use.