Determination of melamine in milk and dairy products by microchip-based high-field asymmetric ion mobility spectrometry combined with solid-phase extraction

This article presents a method for sensitive, fast and quantitative determination of melamine in milk and dairy products using high-field asymmetric ion mobility spectrometry (FAIMS). The solid-phase extraction (SPE) technology was used for purification after the sample was extracted by organic solvents, and followed by the analysis of FAIMS . The measurement parameters and variables that affect the FAIMS detection have been investigated, and optimum conditions have been obtained as follows: the carrier gas flow rate is 1.6   L   min −1 , the headspace sampler temperature is 150   °C, the pressure is 1   atm, and the humidity is 2.0   g   m −3 . The results showed that the SPE–FAIMS method can detect melamine in samples with a concentration down to 0.1   mg   kg −1 . The ion intensity has a linear relationship with melamine concentration in the range from 0.3   mg   L −1 to 25   mg   L −1 , with a good linearity of 0.9975. The limits of detection (LOD) and limits of quantification (LOQ) are 0.1   mg   kg −1 and 0.3   mg   kg −1 in milk and dairy products, respectively, and the relative standard deviation is less than 8.0%. The results demonstrated that FAIMS has great potential as a powerful tool for food analysis and safety inspection.