A fully automatic cross used solid-phase extraction online coupled with ultra-high performance liquid chromatography-tandem mass spectrometry system for the trace analysis of multi-class pharmaceuticals in water samples.

A fully automatic system, which integrated cross used solid-phase extraction with ultra-high performance liquid chromatography-tandem mass spectrometry, was developed and validated for the simultaneous determination of multi-class pharmaceuticals (62 in total) in Milli-Q water, tap water, lake water, and ground water. The online system allowed the cross-utilization of two SPE columns without significant carryover and achieved an automatic, sensitive and fast analysis, requiring about 14 min per analysis. The features of the online system were systematically investigated and the analytical conditions were fully optimized. Sixty-two pharmaceuticals were divided into two groups (acidic and basic) under different extraction conditions to increase the extraction efficiency. Under optimal conditions, all the correlation coefficients were greater than 0.9929. The LODs and the LOQs were in the range of 0.00119-0.623 ng L and 0.00475-2.49 ng L, respectively. The RSDs% for the intra-/inter-day precision were less than 10.6% and 15.6%, respectively. The system recoveries ranged from 80.7 to 119.9%. Compared with the offline SPE method, the online cross used SPE-UHPLC-MS/MS method obtained higher sensitivity and reduced manual operations. Compared with the existing online SPE systems, this system can reduce the time per analysis. Finally, this online system was applied to the analyses of three real water samples. Based on the results, the online cross used SPE-UHPLC-MS/MS system as an automatic, sensitive and efficient technique showed great promise for the future in the trace analysis of multi-class pharmaceuticals in complex aqueous samples.