Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada.
Laboratory Services Branch, Ontario Ministry of the Environment, Conservation and Parks, Toronto, Ontario, M9P 3V6, Canada; School of Environmental Studies, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
Environ Pollut. 2020 Jun;261:114092. doi: 10.1016/j.envpol.2020.114092. Epub 2020 Jan 29.
Although passive sampling is widely accepted as an excellent tool for environmental monitoring, their integration with suspect or non-targeted screening by high-resolution mass spectrometry has been limited. This study describes the application of the organic-diffusive gradients in thin-films (o-DGT) passive sampler as a tool for accurate measurement of both targeted and suspect polar organic contaminants (primarily pharmaceuticals) in wastewater. First, performance of o-DGT was assessed alongside the polar organic chemical integrative sampler (POCIS) and active sampling at two wastewater treatment facilities using targeted analyses. Overall, water concentrations measured by o-DGT, POCIS, and 24-hr integrative active samples were in good agreement with each other. There were exceptions, including a systematic difference between o-DGT and POCIS at certain sites that we propose was a result of site-specific conditions and a difference in sampling rates between the two techniques. The second component of this work involved suspect screening of the o-DGT extracts using high-resolution, high mass accuracy quadrupole time-of-flight mass spectrometry (QTOF). Lamotrigine, venlafaxine, and des-methylvenlafaxine were three suspect compounds identified and selected as proof-of-concept case studies to determine the feasibility and accuracy of o-DGT for estimating water concentrations based upon predicted sampling rates using a previously validated o-DGT diffusion model. Semi-quantification of the suspect compounds was conducting using an average surrogate response factor based on the suite of compounds measured by the targeted analyses. This, combined with the modelled sampling rates provided time-weighted average wastewater concentrations of the identified suspects within a factor of 2 of the true value, confirmed by isotope dilution with mass labelled internal surrogates. To the knowledge of the authors, this work is the first to demonstrate the utility of the o-DGT passive sampler as a potential environmental screening tool that can be integrated into the rapidly advancing field of non-targeted high resolution mass spectrometry.
尽管被动采样被广泛认为是环境监测的一种极好工具，但它与高分辨率质谱的可疑或非靶向筛选的结合一直受到限制。本研究描述了有机扩散梯度薄膜（o-DGT）被动采样器的应用，作为准确测量废水目标和可疑极性有机污染物（主要是药物）的工具。首先，在两个废水处理厂使用靶向分析评估了 o-DGT 与极性有机化学积分采样器（POCIS）和主动采样的性能。总体而言，o-DGT、POCIS 和 24 小时积分主动采样测量的水样浓度彼此之间非常吻合。也有例外，包括在某些站点 o-DGT 和 POCIS 之间存在系统差异，我们认为这是由于特定站点的条件和两种技术之间的采样率差异造成的。这项工作的第二部分涉及使用高分辨率、高质量精度四级杆飞行时间质谱（QTOF）对 o-DGT 提取物进行可疑筛选。拉莫三嗪、文拉法辛和去甲文拉法辛是鉴定出的三种可疑化合物，作为概念验证案例研究，以确定 o-DGT 基于先前验证的 o-DGT 扩散模型预测的采样率来估计水样浓度的可行性和准确性。使用基于靶向分析测量的化合物套件的平均替代物响应因子对可疑化合物进行半定量分析。这一点，再加上模型化的采样率，提供了所识别的嫌疑物的时间加权平均废水浓度，与真实值的因子在 2 以内，这通过用质量标记的内部替代物进行同位素稀释得到了证实。据作者所知，这项工作首次证明了 o-DGT 被动采样器作为一种潜在的环境筛选工具的实用性，它可以集成到快速发展的非靶向高分辨率质谱领域。
