Extending analysis of environmental pollutants in human urine towards screening for suspected compounds

Today there is a large difference in the number of chemicals of commerce and the number of chemicals being monitored in environmental and human samples. During the last decades suspect screening methods have been developed to increase the number of monitored analytes. Peaks detected during high resolution mass spectrometry full scan measurements are compared to a list of suspect chemicals with known exact masses. These methods, however, have so far focused on environmental samples. Thus we present a method development for a suspect screening of human urine samples. The sample preparation techniques and instrumental analysis were tested by target chemicals with a wide range of properties. A combination of direct injection and QuEChERS extraction followed by liquid chromatography coupled to high resolution mass spectrometry was able to detect 33 of the 40 spiked target compounds at 30-120% absolute recovery. For suspect evaluation peaks were deconvoluted and aligned with the software MZmine followed by R script processing. Comparing detected and in-silico fragmentation, nine suspect chemicals could be tentatively identified in a pooled human urine sample and four of these were confirmed by a reference standard.