GB/T 23741-2025 in English

Standard Revision Background and Technological Evolution

GB/T 23741-2025, the latest national standard for the determination of barbiturates in feed, integrates and replaces the two older standards, GB/T 20363-2006 and GB/T 23741-2009. This revision reflects significant advancements in feed safety testing technology in China. Key technical changes include: expansion of the method's scope of application, enhanced detection sensitivity, optimization of sample pretreatment procedures, and standardization of data processing methods.

Comparative Analysis of Detection Methods

Analysis of Key Technological Innovations

The new standard achieves several significant technical breakthroughs: First, the adoption of the LC-MS/MS method increases detection sensitivity by 50-fold, enabling more effective monitoring of trace barbiturate residues in feed; second, the use of isotope internal standard quantification significantly improves the accuracy and reliability of test results; third, the optimized sample pretreatment process significantly reduces matrix interference and improves detection efficiency.

Key Technical Points of Sample Pretreatment

The standard specifies a detailed sample preparation process: After extraction with acetonitrile, the sample is cleaned up using a specialized solid-phase extraction cartridge containing a variety of fillers, including N-propylethylenediamine (PSA), C18, synthetic graphitized carbon black, and an enhanced fat-removing adsorbent, to effectively remove interfering substances in the feed matrix. The cleaned sample is concentrated by nitrogen purge before analysis.

Chromatographic Condition Optimization Analysis

For the LC-MS/MS method, the standard recommends the use of a C18 column (100mm×2.1mm, 1.8μm) and gradient elution using acetonitrile-0.005mol/L ammonium acetate solution as the mobile phase. Mass spectrometry detection employed electrospray negative ionization mode and multiple reaction monitoring (MRM) mode, with characteristic ion pairs and optimal collision energy set for each barbiturate.

Method Validation and Quality Control

The standard requires that the correlation coefficient for establishing the standard curve be no less than 0.99. Under repeatability conditions, the absolute difference between two independent test results of the LC-MS/MS method should be no greater than 20% of the arithmetic mean, while the HPLC method requires no greater than 10%. Such strict quality control requirements ensure the reliability and comparability of the test results.

Implementation Recommendations and Application Guidance

For testing laboratories of different sizes, we recommend that: laboratories equipped with liquid chromatography-tandem mass spectrometry prioritize LC-MS/MS for greater sensitivity and accuracy; for routine monitoring, HPLC can be used for initial screening. In actual operations, special attention should be paid to the preparation and storage conditions of standard solutions to ensure the accuracy of test results.

Significance and Impact of Standard Implementation

The implementation of GB/T 23741-2025 will greatly enhance China's monitoring capabilities for barbiturate residues in feed, providing strong technical support for feed product quality and safety. At the same time, this standard aligns with advanced international testing methods, providing technical support for China's feed export trade and helping to break down technical trade barriers.