This standard specifies the method for determining the content of chelating agents in detergents. The content of chelating agents shall not exceed 2% (m/m). This method is applicable to the determination of the content of ethylenediaminetetraacetic acid (EDTA) and its salts in detergents. GB/T 15916-1995 Determination of the content of surfactant chelating agents Titration method GB/T15916-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Surfactants
Determination of chelating agent content-Titrimetric methodbzxZ.net
Surface active agents-Determination of chelating agent content-Titrimetric methodGB/T15916-1995
This standard is equivalent to the international standard IS04325-1990 Soaps and detergents-Determination of chelating agent content-Titration method". 1 Content and scope of application
This standard specifies the method for determining the chelating agent content in detergents. The chelating agent content shall not exceed 2% (m/m). This method is applicable to the determination of ethylenediaminetetraacetic acid (EDTA) and its salts in detergents. The applicability of this method should be confirmed before determining the content of other chelating agents or the content of EDTA in the presence of other chelating agents. 2 Reference standards
GB/T6368 Determination of pH value of aqueous surfactant solution - Potentiometric method GB/T6372 Sample separation method for powdered surfactant and detergent GB/T6682 Specifications and test methods for water used in analytical laboratories GB/T13173.1 Sample separation method for detergents
3 Principle
Dissolve the sample in water, adjust the pH value of the solution to 4.6, and titrate it with copper sulfate standard titration solution using 1-(2-pyrazo)-2-phenol as an indicator.
4 Reagents and materials
4.1 Laboratory distilled water (GB/T6682): Grade 3 water; 4.2 Hydrochloric acid (GB 622) solution: c(HCl)=5 mol/L 4.3 Acetic acid solution: pH=4.6\, mix equal volumes of acetic acid (GB670) solution, c(CH.CO0H)=0.4 mol/L and sodium hydroxide (GB629) solution, c(NaOH)=0.2 mal/L 4.4 Copper sulfate (CuSO,5H,O) (GB665) standard titration solution: c(CuSO,)=0.0100 mol/L, weigh 2.522 g of copper sulfate pentahydrate (CuSO5H,0) with a purity of 99% (m/m)2, accurate to 0.001 g, dissolve in water, dilute to 1000 mL, and mix. Instructions for use:
1] pH = 4.65 in ISU 4325.
2) The purity of IS04325 is at least 99.5% (m/m). Approved by the State Administration of Technical Supervision on December 20, 1995 and implemented on August 1, 1996
GB/T15916-1995
4.5PAN [1-(2-pyridyl azo)-2-phenol indicator solution: 0.1%
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