GB/T 6488-2022Liquid chemicals—Determination of refractive index (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents" drafted.

This document replaces GB/T 6488-2008 "Determination of Refractive Index of Liquid Chemical Products (20°C)", and is consistent with GB/T 6488-2008 In addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) Changed the temperature range (see Chapter 1, Chapter 1 of the 2008 edition);

b) Added the principle of automatic refractometer (see 4.2);

c) Changed the requirements for Abbe refractometers (see 6.1, 5.1 of the 2008 edition);

d) Changed the correction method of Abbe refractometer (see 7.1, 6.2 of the 2008 edition);

e) Added automatic refractometer measurement method (see 7.2);

f) Added the content of the test report (see Chapter 8).

1 Scope

This document describes a method for determining the refractive index of liquid chemical products using an Abbe refractometer and an automatic refractometer.

This document is suitable for liquefaction of transparent or translucent, temperature range of 20°C~60°C, refractive index range of 1.3000~1.7000 Determination of industrial products.

2 Normative references

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, dated citations documents, only the version corresponding to that date applies to this document; for undated references, the latest edition (including all amendments) applies to this document.

GB/T 6682 Analysis Laboratory Water Specifications and Test Methods

JJG130 Working glass liquid thermometer

JJG625 Abbe Refractometer

JJG2003 Thermocouple

3 Terms and Definitions

The following terms and definitions apply to this document.

4 Principles

4.1 Abbe's refractometer The light from the measured material enters the prism and is refracted, then it conforms to the formula (1) of the law of refraction. sini (1) where. i ---incidence angle; r --- refraction angle;

N --- the refractive index of the prism; n ---Refractive index of the measured substance.

From the optically sparser medium to the optically denser medium, the incident angle is greater than the refraction angle, so that the incident angle i=90°, and substituting into formula (1), we get.