色谱

色谱 ›› 2025, Vol. 43 ›› Issue (4): 345-354.DOI: 10.3724/SP.J.1123.2024.07017

• 研究论文 • 上一篇    下一篇

固相萃取-气相色谱-静电场轨道阱高分辨质谱测定海水中4类34种含氯持久性有机污染物

高梦浩1, 栗笑迎1,*(), 高媛2,*(), 张海军2, 陈吉平2   

  1. 1.大连海事大学环境科学与工程学院,辽宁 大连 116026
    2.中国科学院大连化学物理研究所,辽宁 大连 116023
  • 收稿日期:2024-07-17 出版日期:2025-04-08 发布日期:2025-03-26
  • 通讯作者: *Tel:(0411)84379972,E-mail:acyoyo@dicp.ac.cn(高媛); Tel:(0411)84109335,E-mail:lixiaoying@dlmu.edu.cn(栗笑迎).
  • 基金资助:
    国家重点研发计划(2022YFC3105500);国家自然科学基金(22276186)

Determination of four classes of 34 chlorinated persistent organic pollutants in seawater by solid-phase extraction and gas chromatography-electrostatic field orbitrap high resolution mass spectrometry

GAO Menghao1, LI Xiaoying1,*(), GAO Yuan2,*(), ZHANG Haijun2, CHEN Jiping2   

  1. 1. College of Environmental Sciences and Engineering, Dalian Maritime University, Dalian 116026, China
    2. Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
  • Received:2024-07-17 Online:2025-04-08 Published:2025-03-26
  • Supported by:
    National Key Research and Development Program of China(2022YFC3105500);National Natural Science Foundation of China(22276186)

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摘要： 海洋在新污染物的环境迁移、转化过程中起到重要作用。海水中新污染物的准确定量是厘清其环境行为、评估其环境风险的基础。本研究采用液液萃取和固相萃取建立海水样品前处理方法,基于气相色谱-静电场轨道阱高分辨质谱(GC-Orbitrap-HRMS)测定海水中4类34种含氯持久性有机污染物(POPs)的定量分析方法,即:25种有机氯农药(OCPs)、6种多氯联苯(PCBs)同系物、短链氯化石蜡(SCCPs)和2种德克隆(DPs)同分异构体。通过优化液液萃取提取溶剂种类,选择二氯甲烷进行萃取。随之对固相萃取不同洗脱溶剂进行评价,最终使用体积比为9∶1的正己烷和丙酮混合溶剂进行洗脱。质谱采用电子轰击源(EI)(正离子模式)监测OCPs和PCBs目标化合物离子,采用负化学源(NCI)监测SCCPs和DPs,内标法定量。结果表明,所建立的方法具有较低的检出限,34种含氯POPs检出限为0.006~2.78 ng/L,定量限为0.02~11.12 ng/L;方法准确度和精密度通过测定目标化合物的加标回收率得到验证,低、中、高3个加标水平下的回收率为70.6%~128.9%,相对标准偏差(n=6)为0.2%~19.2%。通过实际海水样品分析显示,SCCPs的检出率和浓度水平最高,质量浓度最高为130.6 ng/L,需要持续重点关注。该方法前处理操作简便,灵敏度高,样品需求量少,适用于大批量海水样本中多种含氯POPs的痕量检测。

关键词: 固相萃取, 气相色谱-静电场轨道阱高分辨质谱, 含氯持久性有机污染物, 海水

Abstract:

Ocean acts as a “sink” for pollutants in the natural environment. Consequently, issues focused on marine pollution from terrestrial origin is attracting increasing attention. Persistent organic pollutants (POPs), including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), short-chain chlorinated paraffins (SCCPs), and dechlorane plus isomers (DPs), are serious hazards for both the environment and humans. These POPs have been widely detected in the marine environment and are typically present at trace levels; however, separating and determining individual contaminants require large amounts of sampling and time. Establishing an accurate analytical method for determining typical POPs is critical for studying their environmental behavior and associated ecological risks to the marine environment.

In this study, we developed a method based on solid-phase extraction (SPE) combined with gas chromatography-electrostatic field orbitrap high resolution mass spectrometry (GC-Orbitrap-HRMS) for determining 34 chlorinated POPs in seawater, including 25 OCPs, six PCB congeners, SCCPs and two DPs. The chromatographic conditions and MS parameters were optimized, and the effects of the extraction solvent and purification method were systematically studied. Dichloromethane exhibited satisfactory extraction efficiencies during the liquid-liquid extraction (LLE) of seawater samples, with recoveries of 73.1%-120.5% for OCPs, 87.2%-101.7% for PCBs, 105.5% for SCCPs, and 74.9%-78.6% for DPs, respectively. Purification using a SPE column with 500 mg of Florisil was adopted, and 9∶1 (v/v) n-hexane/acetone was confirmed as the eluent with recoveries between 68.2% and 122.8% for all the 34 chlorinated POPs. A DB-5MS (15 m×0.25 mm×0.10 μm) capillary chromatographic column was used to separate the target compounds, with an electron ionization (EI) source used to detect OCPs and PCBs, whereas SCCPs and DPs were determined in negative chemical ionization (NCI) source. All target compounds were analyzed in full-scan mode. An internal standard quantification method was used for OCPs and SCCPs while isotope dilution quantification was used for PCBs and DPs. The severe interference observed during the detection of chlorinated POPs in the mixture of co-extracted substances was completely eliminated following the purification.

The 34 target chlorinated POPs exhibited good linearities in their corresponding ranges, with correlation coefficients (R2) exceeding 0.9. The method demonstrated low detection limits under the optimized conditions, with values of 0.009-0.061 ng/L for the 25 OCPs, 0.006-0.016 ng/L for the six PCBs, 2.78 ng/L for the SCCPs, and 0.021-0.023 ng/L for the two DPs, with lower limits of determination of 0.06-0.24, 0.02-0.06, 11.12, and 0.08-0.09 ng/L, respectively. Accuracy and precision were validated by the recoveries of samples spiked at low, medium, and high levels, which ranged between 70.6% and 128.9%. Relative standard deviations (n=6) were determined to be 0.2%-19.2%. These results highlight the suitability of the developed method for analyzing trace amounts of chlorinated POPs in seawater. The method is characterized by simple sample pretreatment, high sensitivity, fast analytical throughput, cost-effectiveness, and good stability for trace-level detection; hence, it is suitable for the rapid and accurate analysis of typical chlorinated POPs in seawater. This method is expected to play a significant role in marine environmental monitoring and the emergency surveillance of seawater pollution. The developed method was applied to seawater samples collected from Bohai, which revealed that the highest detection frequency (90%) was recorded for the SCCPs, while α-hexachlorocyclohexane (α-HCH) was only detected in 30% of the samples. All other OCPs were below the detection limit. PCB-52 was the only PCB congener detected in the seawater samples. The SCCPs were detected in much higher concentrations than the other POPs, with the highest value of 130.6 ng/L recorded. Consequently, particular attention must be paid to SCCPs.

Key words: solid-phase extraction (SPE), gas chromatography-electrostatic field orbitrap high resolution mass spectrometry (GC-Orbitrap-HRMS), chlorinated persistent organic pollutants (POPs), seawater

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