Changing the source on many an LC/MS/MS instrument from ESI to APCI, and vice versa, involves cooling the source, manual removal and installation of the new source, followed by heating of the new source to the operating temperature, resulting in low throughput for analyses utilizing both ESI and APCI sources. Conversely, the PerkinElmer QSight LC/MS/MS features a dual ESI and APCI source, allowing for the collection of data in two complementary modes, thus maximizing output from a single injection. This study demonstrates that the QSight 220, with its dual independent sources capable of measuring in both ESI and APCI modes, can cover different classes of compounds with lower limits of quantitation, even in a complex matrix.