GB/T 36791-2018Determination of bromine in organic flame retardant—Oxygen bomb combustion-ion selective electrode method (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This standard specifies the method for the determination of bromine content in bromine-containing organic flame retardant chemicals by oxygen bomb combustion-ion selective electrode method.

This standard applies to the determination of bromine content in bromine-containing organic flame retardant chemicals.

This standard does not apply to insoluble bromides present in bromine-containing organic flame retardant chemicals or produced during combustion.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 6682 Analytical laboratory water specifications and test methods

GB/T 14402 Determination of combustion calorific value of building materials and products

3 Principle

The sample is fully combusted in an oxygen bomb combustion drum containing an alkaline solution under pure oxygen conditions, and the bromine is converted into bromide ions and absorbed by the alkaline solution.

The bromine content in the absorbing solution was then determined using a bromide ion selective electrode.

4 Reagents

4.1 Unless otherwise stated, the reagents used in this standard are of analytical grade, and the water used is the third grade water specified in GB/T 6682.

4.2 Potassium hydroxide solution [c(KOH) = 0.5 mol/L]. 2.8 g of potassium hydroxide was dissolved in 100 mL of water.

4.3 Hydrogen peroxide solution [c(H2O2)=3%]. 10 mL of a 30% strength hydrogen peroxide solution was diluted to 100 mL.

4.4 Bromide standard storage solution [c(Br)]=1.0mol/L. Potassium bromide is dried at 130 °C for 2 h in advance, and then accurately weighed 119.0 g, dissolve in water, then transfer to a 1000mL volumetric flask and dilute to volume, then obtain bromide standard storage solution.

4.5 Bromide standard solution A[c(Br)=100.0mmol/L]. Pipette 50.0mL bromide standard storage solution in a 500mL volumetric flask, dilute to the mark with water and mix well.

4.6 Bromide standard solution B[c(Br)=10.0mmol/L]. Pipette 50.0mL of bromide standard solution A in a 500mL volumetric flask, dilute to the mark with water and mix.

4.7 Ionic strength modifier [c(KNO3)=1.0mol/L]. Dissolve 101.1g of potassium nitrate (KNO3) in about 500mL of water and transfer into a 1000 mL volumetric flask, add water to volume.

5 Instruments

5.1 Bromide ion selective electrode, the concentration of bromide ion is required to be in the range of 5.0 x 10^-6mol/L~1.0mol/L, and the electrode potential and bromide ion concentration […]