Simultaneous Determination of 10 Photoinitiators in Milk by Solid-Phase Microextraction Coupled with Gas Chromatography/Mass Spectrometry.

Photoinitiators (PIs) are widely used in food packaging materials, can migrate easily from packaging materials to food, and cause food contamination. It is essential to establish a method of determining PIs residues in food. A new method for simultaneously determining 10 kinds of PIs in milk has been established by using solid-phase microextraction (SPME) combined with a simple method of protein precipitation as the pretreatment approach and gas chromatography/mass spectrometry as the detecting technique. The limits of detection for 10 PIs in different milks were between 0.05 and 1.4 μg/L (skimmed milk), between 0.07 and 2.2 μg/L (semi-skimmed milk), between 0.11 and 4.4 μg/L (whole milk), respectively. The recoveries were from 71.5% to 133.5%, and the relative standard deviations were less than 15%. Twelve kinds of packed milk with different brands and fat contents were determined using this method.