Reliable screening of pesticide residues in maternal and umbilical cord sera by gas chromatography-quadrupole time of flight mass spectrometry

The widespread use of pesticides induces heavy adverse effects on human health, especially for the pregnant women and the newborns. In this study, a screening method has been developed for the determination of multi-pesticides in maternal and umbilical cord sera. All pesticides in sera were collected using solid phase extraction (SPE), and analyzed by gas chromatography-quadrupole time of flight mass spectrometry (GC-QTOF MS). To set up the quality criteria, a database of 50 pesticides was created and the accurate masses of 3 up to 5 representative ions with their intensity ratios were included for each pesticide. In addition, a novel "identification points" (IPs) system relying on the accurate MS1 and MS2 spectra was used to interpret the data for each suspected pesticide. The methodology was then applied to a pair of maternal and umbilical cord sera. A total of six pesticide residues were screened out successfully. In conclusion, GC-QTOF MS combined with an accurate mass database seemed to be one of the most efficient tools for systematic pesticide analysis.