Biogeochemistry Research Centre, Plymouth University, Drake Circus, Plymouth PL4 8AA, UK.
Chemosphere. 2013 Nov;93(9):1655-64. doi: 10.1016/j.chemosphere.2013.03.011. Epub 2013 Jul 12.
'Naphthenic acids' (NAs) in petroleum produced water and oil sands process water (OSPW), have been implicated in toxicological effects. However, many are not well characterized. A method for fractionation of NAs of an OSPW was used herein and a multi-method characterization of the fractions conducted. The unfractionated OSPW acidic extract was characterized by elemental analysis, electrospray ionization-Orbitrap-mass spectrometry (ESI-MS), and an esterified extract by Fourier Transform infrared (FTIR) and ultraviolet-visible (UV) absorption spectroscopy and by comprehensive multidimensional gas chromatography-MS (GCxGC-MS). Methyl esters were fractionated by argentation solid phase extraction (Ag(+) SPE) and fractions eluting with: hexane; diethyl ether: hexane and diethyl ether, examined. Each was weighed, examined by elemental analysis, FTIR, UV, GC-MS and GCxGC-MS (both nominal and high resolution MS). The ether fraction, containing sulfur, was also examined by GCxGC-sulfur chemiluminescence detection (GCxGC-SCD). The major ions detected by ESI-MS in the OSPW extract were assigned to alicyclic and aromatic 'O2' acids; sulfur was also present. Components recovered by Ag(+) SPE were also methyl esters of alicyclic and aromatic acids; these contained little sulfur or nitrogen. FTIR spectra showed that hydroxy acids and sulfoxides were absent or minor. UV spectra, along with the C/H ratio, further confirmed the aromaticity of the hexane:ether eluate. The more minor ether eluate contained further aromatics and 1.5% sulfur. FTIR spectra indicated free carboxylic acids, in addition to esters. Four major sulfur compounds were detected by GCxGC-SCD. GCxGC-high resolution MS indicated these were methyl esters of C18 S-containing, diaromatics with ≥C3 carboxylic acid side chains.
“环烷酸”（NAs）存在于石油生产水中和油砂加工水中，已被证实具有毒性作用。然而，许多 NAs 并未得到很好的描述。本文采用了一种分离油砂加工水 NAs 的方法，并对分离得到的馏分进行了多方法表征。采用元素分析、电喷雾电离-轨道阱质谱（ESI-MS）对未分级的油砂加工水酸性提取物进行了表征，采用傅里叶变换红外（FTIR）和紫外-可见（UV）吸收光谱以及全面多维气相色谱-质谱（GCxGC-MS）对酯化提取物进行了表征。采用银（+）固相萃取（Ag(+) SPE）对甲酯进行了分离，并用正己烷、二乙醚：正己烷和二乙醚洗脱，分别对各馏分进行了称重、元素分析、FTIR、UV、GC-MS 和 GCxGC-MS（包括常规分辨率和高分辨率 MS）分析。含硫的乙醚馏分也采用气相色谱-硫化学发光检测（GCxGC-SCD）进行了分析。OSPW 提取物中 ESI-MS 检测到的主要离子被分配到环烷酸和芳烃“O2”酸；还存在硫。Ag(+) SPE 回收的成分也是环烷酸和芳烃的甲酯；这些甲酯中硫和氮含量很少。FTIR 谱表明羟基酸和亚砜不存在或含量很少。紫外光谱以及 C/H 比进一步证实了正己烷：乙醚洗脱物的芳香性。次要的乙醚洗脱物含有更多的芳烃和 1.5%的硫。FTIR 谱表明，除了酯外，还存在游离羧酸。GCxGC-SCD 检测到了 4 种主要的含硫化合物。GCxGC-高分辨率 MS 表明这些是 C18 含硫、二芳烃的甲酯，具有≥C3 羧酸侧链。
