Studies of Labware Contamination during Lipid Extraction in Mass Spectrometry-Based Lipidome Analysis

In lipidomic analysis, plasticware is increasingly being used for lipid extraction and other sample processing procedures over glassware. However, a systematic investigation of the consequences of plasticware use on mass spectrometry (MS)-based lipidome analysis is lacking. In this work, we present an analytical approach for detecting and comparing solvent and labware contaminants encountered in lipidomic workflows. It is shown that the contaminant profiles varied widely between microcentrifuge tubes from different manufacturers. The most suitable polypropylene tubes tested introduced 847 labware-originating contaminant m/z's when three different manufacturing batches were tested for Folch lipid extractions. Of particular concern is that 21 primary amide and fatty acid surfactants were introduced that were identical to biological endogenous lipids, 16 of which had not been previously reported as leachables from polypropylene materials. Alternatively, the use of borosilicate glassware and PTFE-lined screw caps introduced 98 different contaminant m/z's across three manufacturing batches tested for Folch extractions. Despite the overwhelming number of labware contaminants introduced, current databases and literature only facilitated the identification of 32 contaminants. To address the dearth of publicly available contaminant information, we provide a comprehensive labware contamination repository containing high-resolution m/z values, adductation information, retention times, and MS/MS spectra. This resource should prove to be valuable for researchers in detecting and distinguishing contaminants from analytes of interest. A companion paper presents a detailed study of how labware contamination can lead to ion-suppression effects on coeluting lipids and interference in the analysis of endogenous lipids, such as those from human sera.