Removal of anionic interferences using high-pH C18 solid-phase extraction for sensitive toxicant screening in household chemical products

Abstract

About 90 million chemicals are currently being developed worldwide and more than 100,000 chemicals are commercially distributed. Among them, household chemical products (HCPs) contain a number of constituents, most of which have not been officially revealed to public except only a few major compounds. The chemicals in HCPs may pose a potential risk to human public health and ecosystems. LC-MS is an effective technique to identify polar toxicants in HCPs. However, it is known that HCPs such as laundry detergent and cleaner contain a high concentration of anionic surfactants, which may interfere ionization of co-eluting analytes. In this study, we developed C18-based solid-phase extraction (SPE) at basic pH for effective removal of abundant anionic surfactants in HCPs prior to LC-MS. Four target HCPs, including a fungicide remover, a fabric softener, a laundry bleach, and a laundry detergent, were selected in order of sales rate. Basic SPE using 0.02% ammonium hydroxide solution was performed to remove anionic surfactants in HCPs as a flow-through. Extracted samples were analyzed using a UHPLC-LTQOrbitrap mass spectrometer, followed by toxicant identification using NIST 17 MS/MS spectral library. As a result, fatty acids and acyl ethanolamide were significantly reduced when using basic SPE compared to acidic SPE. Decamethylcyclopentasiloxane and 1-aminocyclohexanecarboxylic acid were detected in the fungicide remover and laundry bleach, respectively. Decamethylcyclopentasiloxane is a toxic compound that has reproductive toxicity and is restricted by REACH. 1-Aminocyclohexanecarboxylic acid is known to cause severe skin and eye irritation. This basic SPE-based method could facilitate a robust and sensitive analysis of toxicants in HCPs.