GB/T 32718-2024Determination of defoliant residues in cotton fibers (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 for standardization documents" Drafting.

This document replaces GB/T 32718-2016 "Determination of Thidiazuron Residues in Cotton". Compared with GB/T 32718-2016, In addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) The scope was changed to add the determination of residues of five defoliants: thiamethoxam, diuron, defoliant, ethephon and cyproconazole (see Chapter 1, Chapter 1 of the 2016 edition);

b) Added sampling requirements (see 7.1);

c) The sample pretreatment method has been changed (see 7.2, 7.1, 7.2, and 7.3 of the 2016 edition);

d) Deleted the HPLC/DAD analysis method (see 7.4 of the 2016 edition);

e) Added HPLC-MS/MS analysis method (see 7.3, 7.4);

f) Added the types of defoliant substances (see Appendix A);

g) Added sampling requirements (see Appendix B).

1 Scope

This document describes the determination of thidiazuron, thiabendazole, and dimethoate in cotton fiber using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Test methods for residual amounts of defoliants such as chloranil, defoliant, ethephon, and cyproconazole.

This document is applicable to the determination of defoliant residues in cotton fibers.

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

GB/T 6682 Specifications and test methods for water used in analytical laboratories

3 Terms and definitions

The following terms and definitions apply to this document.

4 Principle

The defoliants in the samples were extracted by ultrasonic method using a mixed solvent of acetonitrile and water. The extract was filtered through a filter membrane and analyzed by HPLC-MS/MS.

The determination was carried out and the quantification was performed by external standard method.

5 Reagents

Unless otherwise specified, all reagents used in the analysis were analytical grade and grade 2 water as specified in GB/T 6682.

5.1 Acetonitrile, chromatographic grade.

5.2 Acetonitrile-water mixed solution: prepared in a volume ratio of 1:1.

5.3 Ammonia water: 0.1%.

5.4 Formic acid: 0.1%.

5.5 Preparation of defoliant standard solution.