GB/T 42426-2023 (English Version)

Standard No.: GB/T 42426-2023
Language: Chinese, English version preview
Release Date: 2023
Published By: General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest: GB/T 42426-2023

Scope: This document describes the determination methods of chemical vapor pressure test by dynamic method, static method, liquid vapor pressure gauge method, percolation method—vapor pressure balance, percolation method—Knudsen cell, percolation method—isothermal thermogravimetric, gas saturation method and rotation method. This document is applicable to the determination of vapor pressure of solids and liquids of 10-10 Pa~105 Pa, and is used for samples that are not decomposed under the determination conditions. If the above conditions are not applicable, refer to the vapor pressure estimation method in Appendix A. The comparison of vapor pressure test methods is shown in Table 1. Table 1 Comparison of vapor pressure test methods Test method Solid substance Liquid substance Expected repeatability Expected reproducibility Dynamic method Low melting point Applicable Maximum 25% Maximum 25% Static method Applicable Liquid vapor pressure gauge method Evaporation method—Recommended range of vapor pressure equilibrium 103 Pa~2×103 Pa 1%~5%1%~5% Applicable 5%~10%5%~10% Applicable Applicable 5%~10%5%~10%102 Pa~105 Pa Applicable Applicable Applicable Evaporation method—Isothermal thermogravimetric 10%~30%—10-10 Pa~1Pa Applicable Applicable Gas saturation method Applicable Applicable Rotation method Applicable Applicable Evaporation method—Knudsen cella 5%~20% Maximum 50%5%~30% Maximum 50%10%~20%—10%~30% Maximum 50%2×103 Pa~105 Pa

Introduction

Interpretation of Chemical Vapor Pressure Test Standards

GB/T 42426-2023 "Chemical Vapor Pressure Test" is an important national standard that aims to standardize the vapor pressure measurement methods of chemical substances. The standard describes in detail a variety of test methods and their scope of application, and provides specific experimental steps and data processing guidelines.

1. Background of Standard Formulation

With the rapid development of the global chemical industry, the assessment of chemical safety is particularly important. Vapor pressure is an important indicator for measuring the volatility of chemicals, which directly affects their diffusion, toxicity and storage safety in the environment. Therefore, it is of great significance to formulate a unified measurement standard.

2. Comparison of standard frameworks

Test method	Scope of application	Accuracy	Operation complexity
Dynamic method	Solid and liquid, recommended boiling point temperature determination	High	Higher
Static method	Applicable to 10Pa~105Pa range	Medium	Moderate
Liquid vapor pressure gauge method	Pure substances and solid samples	High	Low
Percolation method - vapor pressure balance	Low vapor pressure determination	Medium	High

3. Characteristics of various test methods

Dynamic methodDetermines vapor pressure by measuring the boiling point temperature of the sample at a specific pressure, and is suitable for low melting point solids and liquids. This method has high accuracy, but the operation is complicated.

Static methodUses a U-tube or pressure gauge to measure vapor pressure, which is suitable for the determination of multi-component samples, but the error is large under low pressure conditions.

4. Implementation Suggestions

Case Study: A chemical company chose the gas saturation method when testing a new pesticide. This method operates at room temperature, avoiding the impact of high temperature on sample performance, and ultimately accurately determines the vapor pressure of the pesticide.

Implementation Suggestions:

Choose a suitable method based on the properties of the sample
Ensure the calibration and maintenance of experimental equipment
Pay attention to personal safety during operation
Properly handle experimental waste

GB/T 42426-2023 history

2023 GB/T 42426-2023 Chemical Vapor Pressure Test