GC-Orbitrap-HRMS with ROIMCR and MSident targeted and non-targeted analysis of persistent organic pollutants in fish-based certified reference materials

The use of fish-based reference materials allows the validation of analytical methods used for the monitoring of persistent organic pollutants (POPs) in environmental samples. Thus, the aim of this work has been to apply and validate the Regions of Interest Multivariate Curve Resolution (ROIMCR) procedure, in a first instance, to quantify POPs using two fish-based certified reference materials (CRM) provided by the Institute of Reference Materials (IRMM); and also to identify, with the MSident program, the presence of more POPs in the same samples. Samples were extracted and analyzed by gas chromatography coupled to an Orbitrap mass spectrometer (GC-HRMS). A targeted analysis was performed to quantify the four certified POPs: hexachlorobenzene (HCBz) and hexachlorobutadiene (HCBu) in ERM®-CE100 and pentachlorobenzene (PeCB) and α, β, γ, and δ-hexachlorocyclohexane (HCH) in ERM®-CE103. Quantitative estimations obtained with ROIMCR method were compared with those obtained using the instrument vendor's Xcalibur software. Two tailed t-tests were performed and good agreement was observed between the two approaches and with the certified values. A non-targeted analysis approach was then performed to characterize other unknown POPs present in the samples. Data processed with the ROIMCR method in the non-targeted acquisition mode was complemented with the MSident chemical identification procedure, which allowed the annotation of several polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), phthalates, and polychlorinated biphenyls (PCBs). The presence of some of these compounds was confirmed with the analysis of validation standard mixture samples containing 43 POPs. The ROIMCR methodology herein proposed allows, in a first instance, the quantitative analysis of multiple unknown contaminants present in the analyzed fish-based certified samples by using GC-HRMS data and also, combined with the MSident program, enables a qualitative analysis which could provide a comprehensive assessment of POP pollution patterns in fish or other environmental samples.