GB/T 35665-2017 in English

Interpretation of GB/T 35665—2017 National Standard of the People's Republic of China

Overview

This standard was proposed by the China Meteorological Administration to standardize the determination of formate and acetate ions in atmospheric precipitation samples. This standard combines the advantages of ion chromatography and provides a scientific and systematic analysis process.

Measurement principle

Ion chromatography separates formate and acetate ions through an anion exchange column and uses a conductivity detector for quantitative analysis. The key to this method is:

• The configuration of the ion chromatograph, including the suppression column and gradient elution system.
• Establishment of calibration curve ensures good linear relationship (r²≥0.99).
• In the process of sample analysis, test solution and blank sample are interspersed to ensure data reliability.

Reagents and instruments

The standard has strict requirements for reagent preparation:

Sample Collection and Analysis

Sterilization measures (such as adding chloroform) should be taken immediately after sample collection, and the samples should be analyzed as soon as possible. Before sample analysis, the samples should be filtered through a 0.45 µm filter membrane to remove suspended particles and microbial interference.

Quality Control and Evaluation

To ensure the accuracy of the analysis results, the standard requires the implementation of the following quality control measures:

1. Stability test:Each batch of samples needs to be interspersed with the analysis of the test solution, and it is determined whether the measurement results are within the range of ±20%.
2. Precision evaluation:Three test solutions and three precipitation samples were analyzed twice, and the relative standard deviation (RSD) was calculated.
3. Accuracy assessment: Use standard samples of known concentration for verification to ensure that the relative deviation is within ±30%.