Evaluation of Matrix Effects in Quantifying Microbial Secondary Metabolites in Indoor Dust Using Ultraperformance Liquid Chromatograph–Tandem Mass Spectrometer

Liquid chromatography–tandem mass spectrometry (LC-MSMS) for simultaneous analysis of multiple microbial secondary metabolites (MSMs) is potentially subject to interference by matrix components. We examined potential matrix effects (MEs) in analyses of 31 MSMs using ultraperformance LC-MSMS. Twenty-one dust aliquots from three buildings (seven aliquots/building) were spiked with seven concentrations of each of the MSMs (6.2 pg/μl–900 pg/μl) and then extracted. Another set of 21 aliquots were first extracted and then, the extract was spiked with the same concentrations. We added deepoxy-deoxynivalenol (DOM) to all aliquots as a universal internal standard. Ten microliters of the extract was injected into the ultraperformance LC-MSMS. ME was calculated by subtracting the percentage of the response of analyte in spiked extract to that in neat standard from 100. Spiked extract results were used to create a matrix-matched calibration (MMC) curve for estimating MSM concentration in dust spiked before extraction. Analysis of variance was used to examine effects of compound (MSM), building and concentration on response. MEs (range: 63.4%–99.97%) significantly differed by MSM (p