Investigation of the Effects of Labware Contamination on Mass Spectrometry-Based Human Serum Lipidome Analysis

Polypropylene
microcentrifuge tubes (MCTs) are increasingly used
in lipidome sample preparation. In the absence of a comprehensive
study evaluating ramifications of plasticware utilization in mass
spectrometry-based lipidomic analyses, we conducted a systematic analysis
to elucidate potential negative effects ascribable to labware contamination
in serum lipidomics. During serum lipid extractions, tested glassware
introduced 24 labware contaminants. In contrast, Eppendorf polypropylene
MCTs contributed 485 contaminant features, many of which could be
erroneously putatively identified as lipids via their m/z values. Eppendorf MCTs contamination engendered
severe ion-suppression of 40 low abundance serum lipids, while generating
mild to modest lipid ion-suppression across a multitude of higher
abundance coeluting lipids. Less compatible polypropylene MCTs from
an alternative manufacturer introduced a staggering 2,949 contaminant m/z values, severely affecting 75 coeluting
serum lipids and causing more frequent and pronounced ion-suppression
instances. Furthermore, by performing serum extractions with varied
initial volumes, it was ascertained that labware-induced lipid ion-suppression
is a dynamic phenomenon, contingent on both lipid and labware contaminant
concentrations where low-abundance lipids are disproportionately impacted
by coelutes of suppressive contaminants. In addition to lipid ion-suppression,
the identification and quantification of 7 fatty acid endogenous serum
lipids were compromised by the leaching of structurally identical
surfactants from MCTs. MCTs artificially introduced 10 additional
primary amides extraneous to serum samples. Utmost caution is imperative
in interpreting data concerning primary amides and fatty acids when
employing plastic labware. Through this investigation, we aspire to
elevate awareness regarding the pernicious impact of labware contamination
on lipidome analysis.