宋丽丽, 赵焕娟, 陈宇飞, 郭冬发, 李慧, 徐加泉. 土壤中重金属形态及有机物组分的电化学-质谱分析[J]. 质谱学报, 2024, 45(3): 354-363. DOI: 10.7538/zpxb.2023.0106
引用本文: 宋丽丽, 赵焕娟, 陈宇飞, 郭冬发, 李慧, 徐加泉. 土壤中重金属形态及有机物组分的电化学-质谱分析[J]. 质谱学报, 2024, 45(3): 354-363. DOI: 10.7538/zpxb.2023.0106
SONG Li-li, ZHAO Huan-juan, CHEN Yu-fei, GUO Dong-fa, LI Hui, XU Jia-quan. Analysis of Heavy Metal Speciation and Organic Compounds in Soil Using Electrochemical Mass Spectrometry[J]. Journal of Chinese Mass Spectrometry Society, 2024, 45(3): 354-363. DOI: 10.7538/zpxb.2023.0106
Citation: SONG Li-li, ZHAO Huan-juan, CHEN Yu-fei, GUO Dong-fa, LI Hui, XU Jia-quan. Analysis of Heavy Metal Speciation and Organic Compounds in Soil Using Electrochemical Mass Spectrometry[J]. Journal of Chinese Mass Spectrometry Society, 2024, 45(3): 354-363. DOI: 10.7538/zpxb.2023.0106

土壤中重金属形态及有机物组分的电化学-质谱分析

Analysis of Heavy Metal Speciation and Organic Compounds in Soil Using Electrochemical Mass Spectrometry

  • 摘要: 本研究建立了一种电化学-质谱(EC-MS)法高通量分析土壤样品中的金属组分和有机物。首先,根据理化性质,将土壤样品中的金属组分和有机物组分分为水溶态、脂溶态、难溶态和可氧化态等4种形态;然后,分别采用萃取、反应、电解等方式对4种形态组分进行在线顺次提取;将提取后的组分在线传输至电喷雾电离源进行离子化,随后进行正、负离子模式检测。实际样品分析结果表明,该方法成功检测出土壤样品中多种水溶态金属盐和有机物(如Mg、Cr、Ni、Zn、Co、Cu、Al、Pb等多种水溶性金属盐,尿素及多种有机胺)、20多种脂溶态有机羧酸、以及难溶态金属盐(Mg、Ni、Cr、Pb、Co)和可氧化态(Cu、Pb)。该方法可为环境评估和环境治理提供技术支持。

     

    Abstract: It is of great significance to analyze the heavy metal speciation and identify the organic compounds in soil. By now, the most of existed methods can not be used for simultaneously analyzing metal-containing compounds and organic components, which require tedious sample preparation and offline separation processes before detection, increasing analytical errors and lengthening analysis time. Herein, based on our previous research, a novel electrochemical mass spectrometry (EC-MS) device was fabricated for online sequential qualitative detection of metal species and organics in soil without sample pretreatment. Firstly, the components were divided into four species, including water soluble, lipid soluble, insoluble and oxidable speciation, and then dissociated by extraction, reaction and electrolysis online. Ultrapure water and CH3OH were employed as eluents to extract water-soluble and lipid soluble species, respectively. EDTA-2Na (CH3OH:H2O=1:1, V/V) solution was used as reactant to dissociate insoluble speciation by chelation. For oxidable speciation, the electrolysis was applied to transform the elements into ions using EDTA-2Na as an electrolyte. Then, the dissociated components were mixed with different charged reagents to form ions for MS detection. For example, the produced inorganic metal ions reacted with EDTA-2Na in situ to form metal-EDTA chelate, the polycyclic aromatic hydrocarbons would chelate with Ag+ to form Ag+-PAHs. For organic compounds, those were easily ionized, would be charged with CH3OH directly. Finally, the charged ions and chelates would be transferred for ESI-MS detection in real time under negative and positive ion modes, respectively. The soil sample collected from farmers’ own vegetable fields in the suburb near the roadside was analyzed by EC-MS. The results showed that the soil sample contains water-soluble Mg, Cr, Ni, Zn, Co, Cu, Al, Pb, urea and various organic amines, lipid soluble carboxylic acids, insoluble Ni, Cr, Pb, and oxidable Cu, Pb. The heavy metals in the sample may come from animal and plant waste, the settlement of road dust and atmospheric suspended particles, etc. Amines may come from urine, pesticides, biological tissues, etc. And the presence of organic acids were related to organisms. It indicated the potential of EC-MS for the rapid qualitative species detection of heavy metals and organics in soil. This method can solve the problems, such as low sensitivity, long analysis time, complex pretreatment operation, large sample dosage, and complex operation process, which can provide a strong technical support for environmental assessment and environmental governance.

     

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