Department of Environmental Science and Analytical Chemistry, Stockholm University , Svante Arrhenius väg 8, SE-10691 Stockholm, Sweden.
Institute for Chemical and Bioengineering, Swiss Federal Institute of Technology, ETH Zurich , Vladimir-Prelog-Weg 1, CH-8093 Zürich, Switzerland.
Environ Sci Technol. 2017 Sep 19;51(18):10633-10641. doi: 10.1021/acs.est.7b02269. Epub 2017 Aug 28.
Accurate quantification of short-chain chlorinated paraffins (SCCPs) poses an exceptional challenge to analytical chemists. SCCPs are complex mixtures of chlorinated alkanes with variable chain length and chlorination level; congeners with a fixed chain length (n) and number of chlorines (m) are referred to as a "congener group" CCl. Recently, we resolved individual CCl by mathematically deconvolving soft ionization high-resolution mass spectra of SCCP mixtures. Here we extend the method to quantifying CCl by introducing CCl specific response factors (RFs) that are calculated from 17 SCCP chain-length standards with a single carbon chain length and variable chlorination level. The signal pattern of each standard is measured on APCI-QTOF-MS. RFs of each CCl are obtained by pairwise optimization of the normal distribution's fit to the signal patterns of the 17 chain-length standards. The method was verified by quantifying SCCP technical mixtures and spiked environmental samples with accuracies of 82-123% and 76-109%, respectively. The absolute differences between calculated and manufacturer-reported chlorination degrees were -0.9 to 1.0%Cl for SCCP mixtures of 49-71%Cl. The quantification method has been replicated with ECNI magnetic sector MS and ECNI-Q-Orbitrap-MS. CCl concentrations determined with the three instruments were highly correlated (R > 0.90) with each other.
准确量化短链氯化石蜡（SCCPs）对分析化学家来说是一个特殊的挑战。SCCPs 是氯代烷烃的复杂混合物，具有可变的链长和氯化程度；具有固定链长（n）和氯原子数（m）的同系物被称为“同系物组”CCl。最近，我们通过对 SCCP 混合物的软电离高分辨质谱进行数学反卷积，解析了各个 CCl。在这里，我们通过引入 CCl 特定的响应因子（RFs）来扩展该方法，这些 RFs 是从具有单一碳链长和可变氯化程度的 17 个 SCCP 链长标准品计算得出的。对每个标准的信号模式在 APCI-QTOF-MS 上进行测量。通过对正态分布对 17 个链长标准品信号模式的拟合进行两两优化，得到每个 CCl 的 RF。通过对 SCCP 技术混合物和环境样品进行加标验证，该方法的准确度分别为 82-123%和 76-109%。计算的和制造商报告的氯化度之间的绝对差异为 -0.9 至 1.0%Cl，用于 49-71%Cl 的 SCCP 混合物。该定量方法已经使用 ECNI 磁扇形 MS 和 ECNI-Q-Orbitrap-MS 进行了复制。三种仪器测定的 CCl 浓度之间具有高度相关性（R > 0.90）。
