GB/T 5009.26-2003 in English

Technical analysis of standard methods

Gas chromatography-thermal energy analyzer (GC-TEA) and Gas chromatography-mass spectrometer (GC-MS) are the core equipment of this standard. The detection objects include four compounds such as N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), and the minimum detection concentration can reach 0.1μg/kg.

Method comparison and selection guide

Key operation precautions

Reagent purity control:Dichloromethane needs to be redistilled until TEA detection has no response to avoid false positive interference;Concentration step:Use KD concentrator to control the temperature ≤55℃ to prevent the target from volatilizing and losing.

Technical evolution background

The 2023 version of the standard mainly modifies the scope of application of pretreatment methods and the requirements for result expression, adds food detection matrix, and expands the detection range by 200%. By introducing a C₁₈ solid phase extraction column to optimize the purification steps, the recovery rate was increased by %pillar-box

Actual application case

A brewery found that the NDMA content curve of conventional samples fluctuated abnormally. By optimizing the amount of sodium hydroxide added during extraction (adjusted to 2 mol/L in the experiment), the false negative problem was successfully solved, and the recovery rate was verified to be increased from 65% to 92%.