Determination of Long Chain Chlorinated Paraffins in Soils and Sediments by High-Performance Liquid Chromatography (HPLC) High Resolution Mass Spectrometry (HR-MS)

Long-chain chlorinated paraffins (LCCPs) have gained attention due to their bioaccumulation and toxicity. However, their determination is hindered by low vapor pressure and limited elution from gas chromatography columns. In this study, ammonium acetate (CH3COONH4) was employed as the mobile phase additive and directly applied to high-performance liquid chromatography coupled with Orbitrap high resolution mass spectrometry (HPLC-Orbitrap HRMS). Acetate adducts [M + CH3COO](-) were selected for quantifying the LCCPs. The mass spectral parameters, such as the radio frequency lens percentage, vaporizer, ion transfer tube temperature, and spray voltage, were optimized. A new analytical strategy for LCCPs was established based on HPLC-Orbitrap HRMS. The accuracy, limits of detection (LOD), and limits of quantification (LOQ) were equal to 94.8% to 109.4%, 7.9 to 16.0 pg/mu L, and 26.3 to 53.3 pg/mu L for the LCCPs, respectively. The linear range was between 0.04 and 10.0 ng/mu L with R-2 values of 0.999 for the LCCPs. The relative standard deviations for intra-day and inter-day precision were from 0.5% to 3.3% and from 0.7% to 7.2%, respectively. This method was validated using 20 sediment and soil samples. For the first time, highly chlorinated (Cl->15) and longer carbon chain length (C->36) homologues of LCCPs were observed in soil. The method was suitable for determining LCCPs while avoiding modified instruments and eliminating the incompatibility of CH2Cl2 with the HPLC mobile phase. Further measurements are required of sediment, soil, and air to better characterize LCCPs in the environment.