A non-target chemometric strategy applied to UPLC-MS sphingolipid analysis of a cell line exposed to chlorpyrifos pesticide: A feasibility study

A non-target chemometrics study based on the application of Multivariate Curve Resolution Alternating Least Squares (MCR-ALS) method to a data set obtained by ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-MS) has been applied to the study of human prostate cancer (DU145) cell line samples treated with the organophosphate pesticide chlorpyrifos (CPF). Full scan UPLC-MS data sets were segmented in 17 different chromatographic windows and submitted to a non-target detailed study. Every one of these chromatographic windows of the different analyzed samples (treated and non-treated with CPF) was column-wise augmented in a new data matrix with their m/z values in the common column mode to preserve the fulfillment of the assumed spectral bilinear model. MCR-ALS was used to recover the elution and mass spectral profiles of the pure components present in each of the analyzed chromatographic windows. ANOVA (p ≤ 0.05) was then applied to compare the areas under the concentration profiles of the MCR-ALS resolved components in the CPS treated and control samples. This analysis allowed the detection of those sphingolipids having their concentration in cells modified by the presence of CPS compared to control samples where this contaminant was absent. Positively identified sphingolipids included sphingomyelins, dihydrosphingomyelin and C16 ceramide. The strategy described in this work is proposed for a general non-target UPLC-MS MCR-ALS analysis of the effect of environmental contaminants in cells in lipidomic and metabonomic studies.