SN/T 5437-2022 in English

Analysis of standard technical framework

Key technological breakthroughs

The standard innovatively uses liquid chromatography-mass spectrometry/mass spectrometer combined with isotope internal standard method (diphenhydramine-D3), and by optimizing the extraction solvent ratio and SCX column purification process, the quantitative limit of complex matrices such as pork is reduced to 5 μg/kg, and the milk matrix is even reduced to 1 μg/kg.

Operational points

Recommendations for the implementation of the standard

1. Laboratories need to regularly verify the nebulizer gas flow rate (recommended 8 L/min) and collision energy (256→167.1 channel maintained at 60 eV) of the electrospray ion source
2. For high-fat samples (such as pig intestines), it is recommended to add a n-hexane defatting step
3. The standard working solution should be prepared and used immediately to avoid degradation of the formic acid-acetonitrile system

Technology evolution analysis

Compared with the 2008 version of the Ministry of Agriculture standard, the progress of this standard is reflected in: ①Introducing isotope internal standards to compensate for matrix effects ②Using 1.8 μm ultra-high efficiency chromatographic columns to increase throughput ③Adding verification data for special matrices such as pig kidneys. In the future, it can develop in the direction of multi-residue joint testing.