Reliable screening and confirmation of 156 multi-class illegal adulterants in dietary supplements based on extracted common ion chromatograms by ultra-high-performance liquid chromatography-quadrupole/time of flight-mass spectrometry

Abstract

An analytical method for the reliable screening and confirmation of 156 illegal drugs (58 erectile dysfunction drugs, 49 synthetic steroids, 26 anabolic steroids, and 23 anti-histamine drugs) in supplementary diets using ultra-high-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UHPLC-Q/TOF-MS) was developed. Various types of supplements (liquid, capsule, powder, pill and tablet) with complicated matrices were pretreated by simple liquid–liquid extraction. The wide scope of 156 target compounds was effectively determined within 15min in the positive ion mode, detecting the compounds at a sub-ppb level. Their MS/MS spectra were preferentially investigated to find diagnostic common ions according to the structural similarity of diverse adulterants. For the rapid screening of multiple classes of the target adulterants, extracted common ion chromatograms (ECICs) based on specific fragments of similar molecular moieties were attempted. A database including the elemental compositions, retention times, and MS/MS spectra was built for the confirmation of adulterants. The established method was validated in terms of the linearity, limits of detection (LOD), precision, and accuracy. The linear correlation coefficient and limit of detection ranged from 0.9880 to 1 and from 0.02 to 16.04ng/mL, respectively. The precision and accuracy of intra- and inter-day experiments for the spiked samples at the range of 0.2 and 16.0ng/mL were from 0.16 to 13.50% and 0.19–11.48%, respectively, with relative standard deviation. Mean recoveries ranged from 81.6 to 124.7%, and relative standard deviation was less than 9.20%. The screening and confirmation method demonstrated the usefulness of UHPLC-Q/TOF-MS combined with ECICs as a promising approach for the analysis of multi-class adulterants. Finally, the established method was successfully applied for the monitoring of several types of dietary supplements in routine analysis.