Pacific and Yukon Laboratory for Environmental Testing, Science & Technology Branch, Pacific Environmental Science Centre, North Vancouver, British Columbia, Canada.
J Chromatogr A. 2013 Feb 22;1278:98-107. doi: 10.1016/j.chroma.2012.12.078. Epub 2013 Jan 11.
Over the past 20 years, oil sands exploration and processing in Canada have grown steadily, leading to the development of intensive large-scale operations in Alberta, Canada. Naphthenic acids (NAs), a complex mixture of aliphatic and alicyclic carboxylic acids, are by-products of oil sands processing and are known to be toxic. While oil sands processing water (OSPW) is contained in tailings ponds, potential seepage and leaking of OSPW and its contaminants into surrounding surface water systems is a concern. The ability to quantify NAs and their isomers in OSPW surrounding water is essential for monitoring these spills. Unfortunately, quantification of NAs and their isomers is challenging due to the complexity of the NA mixtures, the lack of commercially available standards, and interference from naturally occurring NA compounds. Techniques such as FT-IR and GC/MS are currently used to analyse NAs, but are limited by poor sensitivity and specificity in the case of FT-IR and long sample preparation and instrument run time for GC/MS. To tackle these issues, a rapid LC/MS method was developed which can quickly quantify NAs in surface water with much better sensitivity and specificity than current methods. This method uses large volume injection, ESI negative mode and a Poroshell LC column to improve the method limits of detection (LOD) and quantitation (LOQ). The method is robust and has no complicated sample preparation steps. The method detection limit (MDL) is 0.01 mg/L (10 ppb) and low limit of quantitation (LLOQ) of 0.1mg/L (100 ppb), both for surface water. The developed method was tested with samples from the oil sands producing region, and demonstrated its applicability for fast screening of surface water samples before resorting to costly high accuracy and high resolution mass spectrometry determination. This is the first very rapid LC/MS method using large volume single column direct injection for quantitative determination of naphthenic acids in surface water.
在过去的 20 年中，加拿大的油砂勘探和加工稳步增长，导致在加拿大艾伯塔省开发了密集的大型作业。环烷酸（NA）是油砂加工的副产品，是一种复杂的脂肪族和脂环族羧酸混合物，已知具有毒性。虽然油砂加工水（OSPW）被包含在尾矿池中，但 OSPW 及其污染物潜在的渗漏和泄漏到周围地表水系统是一个令人关注的问题。定量测定 OSPW 周围水中的 NA 及其异构体的能力对于监测这些溢漏物至关重要。不幸的是，由于 NA 混合物的复杂性、缺乏市售标准以及天然存在的 NA 化合物的干扰，定量测定 NA 及其异构体具有挑战性。目前使用傅里叶变换红外光谱（FT-IR）和气相色谱/质谱（GC/MS）等技术来分析 NA，但 FT-IR 的灵敏度和特异性较差，GC/MS 的样品制备和仪器运行时间较长，因此受到限制。为了解决这些问题，开发了一种快速 LC/MS 方法，可以快速定量地表水的 NA，其灵敏度和特异性比现有方法要好得多。该方法使用大体积进样、ESI 负离子模式和 Poroshell LC 柱，以提高方法的检测限（LOD）和定量限（LOQ）。该方法稳健，没有复杂的样品制备步骤。方法检测限（MDL）为 0.01mg/L（10ppb），地表水的低定量限（LLOQ）为 0.1mg/L（100ppb）。该方法已在产油砂地区的样品中进行了测试，证明了在采用昂贵的高精度和高分辨率质谱测定之前，该方法适用于快速筛选地表水样品。这是第一个使用大体积单柱直接进样快速 LC/MS 方法，用于定量测定地表水的环烷酸。
