Identification of an Analytical Method Interference for Perfluorobutanoic Acid in Biological Samples

Abstract

The investigation of per- and polyfluorinated alkyl substances (PFAS) in environmental and biological samples relies on both high- and low-resolution mass spectrometry (MS) techniques. While high-resolution MS (HRMS) can be used for identification and quantification of novel compounds, low-resolution MS is the more commonly used and affordable approach for studies examining previously identified PFAS. Of note, perfluorobutanoic acid (PFBA) is one of the smaller PFAS observed in biological and environmental samples and has only one major MS/MS transition, preventing the use of qualitative transitions for verification. Recently, our laboratories undertook a targeted investigation of PFAS in the human placenta from high-risk pregnancies utilizing low-resolution, targeted MS/MS. Examination of placental samples revealed a widespread (n = 93/122 (76%)) chemical interferent in the quantitative ion channel for PFBA (213 → 169). PFBA concentrations were influenced by up to ∼3 ng/g. Therefore, additional chromatographic and HRMS/MS instrumentation was utilized to investigate the suspect peak and putatively assign the identity of the interfering compound as the saturated oxo-fatty acid (SOFA) 3-oxo-dodecanoic acid.

PFAS and Precursor Bioaccumulation in Freshwater Recreational Fish: Implications for Fish Advisories

“…The TOP assay oxidizes FBSA to the C3 PFCA (PFBA), which can be challenging to measure at low concentrations in biological tissues. Short-chain PFAS coelute with many biological molecules in LC-MS/MS analysis due to their small size . This coelution with matrix interferences affects ionization efficiency and increases the background, leading to reduced and variable recovery and higher detection limits.…”

“…7:3 FTCA was detected by LC-MS/MS in >90% of fish samples measured but was excluded from further evaluation due to the presence of a biological interference identified by HRMS (SI Section 1.13). Some biological molecules can interfere with quantification of certain PFAS if they have the same nominal mass in unit resolution . Complementary measurements using HRMS are useful since interfering molecules in biological samples can be distinguished from PFAS using exact mass measurements.…”

“…Some biological molecules can interfere with quantification of certain PFAS if they have the same nominal mass in unit resolution. 36 Complementary measurements using HRMS are useful since interfering molecules in biological samples can be distinguished from PFAS using exact mass measurements.…”

Trophic Magnification of Short-Chain Per- and Polyfluoroalkyl Substances in a Terrestrial Food Chain from the Tibetan Plateau

“…The sample pretreatment methods, instrumental parameters, and quality control for analysis of PFASs and stable isotopes are presented in the Supporting Information (Texts S2–S5 and Table S2). Because endogenous compounds might cause interference in the quantification of PFASs in biological samples by triple-quadruple mass spectrometry (MS), , high-resolution Orbitrap MS was employed to monitor whether there was interference with the analyzed PFASs in muscle samples (Text S3). Method detection limits (MDLs) of PFASs for all sample types are listed in Table S3.…”

Emerging and Legacy Per- and Polyfluoroalkyl Substances in an Elderly Population in Jinan, China: The Exposure Level, Short-Term Variation, and Intake Assessment

“…The optimized mass spectrometry parameters for the target compounds are shown in Table S1. In addition, considering that the potential interference of PFBA existed in the biota samples, 27 PFBA was confirmed using high-resolution mass spectrometry. The related information is shown in the Supporting Information (Text S2 and Figure S2).…”