CN-121994905-A - Method and device for simultaneously testing trace mercury and arsenic in water body through mass spectrometry

CN121994905ACN 121994905 ACN121994905 ACN 121994905ACN-121994905-A

Abstract

The invention relates to the field of physicochemical analysis of chemical substances, in particular to a method and a device for simultaneously testing trace mercury and arsenic in a water body by mass spectrometry; the method comprises the steps of introducing hydrogen into a water body sample to obtain gas a, introducing the gas a into an enrichment device, introducing carrier gas into the enrichment device, heating, and continuously introducing the gas b exhausted from the enrichment device into an atomization chamber of an inductively coupled plasma mass spectrometer by using the carrier gas, or directly introducing the gas a into the atomization chamber by using the carrier gas. According to the invention, the hydrogen reacts with mercury and arsenic elements in the water sample to generate mercury simple substance and arsenic hydride, so that the interference of a sample substrate on a test is avoided, and meanwhile, the salt in the sample is prevented from being deposited in a interception cone and an atomization chamber in the atomization process, thereby reducing the replacement frequency of key parts, reducing the running cost of equipment and improving the accuracy of a test result.

Inventors

WEN LIQUN
CHEN YANG
ZHANG YONGXIN
BAI YUSHUANG
WU XIANWEI
LUO ZHIQIN

Assignees

湖南省青山生态环境监测技术研究院

Dates

Publication Date: 20260508
Application Date: 20260209

Claims (10)

1. A method for simultaneously testing trace mercury and arsenic in a water body by a mass spectrometry method is characterized in that a water body sample is placed in a reaction device, and hydrogen is introduced into the sample at 60-90 ℃ to obtain a gas a; carrying gas a into an atomization chamber of an inductively coupled plasma mass spectrometer by using carrier gas to perform elemental analysis to obtain concentration information of mercury and arsenic in a sample; the method (2) comprises the steps of introducing the gas a into an enrichment device for enrichment, introducing carrier gas into the enrichment device for heating, continuously introducing the gas b exhausted from the enrichment device into an atomization chamber of an inductively coupled plasma mass spectrometer by using the carrier gas for elemental analysis to obtain concentration information of mercury and arsenic in a sample, and forming amalgam by the enrichment device for enriching mercury.
2. The method for simultaneously testing trace mercury and arsenic in a water body by mass spectrometry according to claim 1, wherein the time for introducing hydrogen into the sample is 3-20 min.
3. The method for simultaneously testing trace amounts of mercury and arsenic in a water body by mass spectrometry according to claim 1, wherein the gas a and/or the gas b is carried into an atomizing chamber of an inductively coupled plasma mass spectrometer by using a carrier gas with a flow rate of 100mL/min to 200 mL/min.
4. The method for simultaneously testing trace mercury and arsenic in a water body by mass spectrometry according to claim 1, wherein in the mode (2), the flow rate of the carrier gas introduced into the enrichment device is 100-500 mL/min, and in the mode (2), the time of introducing the carrier gas into the enrichment device is 10-40 min.
5. The method for simultaneously testing trace mercury and arsenic in water by mass spectrometry according to claim 1, wherein the enrichment device adopts one or more than two of gold, palladium and nano molybdenum disulfide as enrichment materials.
6. The method for simultaneous testing of trace amounts of mercury and arsenic in a body of water by mass spectrometry according to claim 1, wherein in mode (2), the heating temperature is 180 ℃ to 250 ℃.
7. The method for simultaneous detection of trace amounts of mercury and arsenic in a water body by mass spectrometry according to claim 1, wherein the water body sample contains a salt-like interfering component.
8. The method for simultaneously testing trace amounts of mercury and arsenic in a water body by mass spectrometry according to any one of claims 1 to 7, wherein a standard sample with a known concentration is prepared, a standard curve is drawn according to a test result of the standard sample, and the mercury and arsenic content in the sample to be tested is calculated according to the standard curve.
9. The method for simultaneously testing trace amounts of mercury and arsenic in a water body by mass spectrometry according to claim 8, wherein the standard sample is prepared with nitric acid as a matrix.
10. The device for simultaneously testing trace mercury and arsenic in a water body through mass spectrometry is used for implementing the method for simultaneously testing trace mercury and arsenic in a water body through mass spectrometry according to any one of claims 1-9, and is characterized by comprising a reaction device, a flow path switching control assembly and an enrichment device, wherein the reaction device is respectively connected with an atomization chamber of an inductively coupled plasma mass spectrometer and the enrichment device through the flow path switching control assembly, and the enrichment device is connected with the atomization chamber of the inductively coupled plasma mass spectrometer through a pipeline.

Description

Method and device for simultaneously testing trace mercury and arsenic in water body through mass spectrometry Technical Field The invention relates to the field of physicochemical analysis of chemical substances, in particular to a method and a device for simultaneously testing trace mercury and arsenic in a water body by mass spectrometry. Background With the development of environmental science, biomedical science and other subjects, the biological availability, toxicity, chemical activity and remobilisation of heavy metal elements in the environment are deeply and deeply known. Among them, mercury and arsenic are two important heavy metal elements, which pose serious threat to the environment and organism health. In particular, mercury and arsenic in seawater are typical high-toxicity trace elements, which can exist in various valence states and organic/inorganic forms, are easy to migrate and transform in complex salt matrixes, and directly influence the bioavailability and the ecological toxicity of the mercury and arsenic. The method is used for accurately analyzing the content and the morphology of mercury and arsenic in seawater, is not only a scientific basis for evaluating the safety and health risks of a marine ecological system, but also an important premise for understanding geochemical circulation, pollution source analysis and cross-medium migration rules. Mercury is a typical highly toxic trace element, and exists in the environment in the forms of elemental mercury, inorganic mercury, organic mercury and the like, wherein the accumulation of methyl mercury through a food chain is particularly harmful to the nervous system of a human body. Because mercury is extremely low in concentration and complex in morphology in nature, accurate analysis faces the double challenges of sensitivity and matrix interference for a long time. The existing detection methods comprise a cold atomic absorption spectrophotometry for measuring water quality mercury (HJ 597-2011), a cold atomic fluorescence spectrophotometry for measuring water quality mercury (HJ 543-2009), a cold atomic absorption spectrophotometry for measuring total mercury in ambient air (HJ 910-2017) and the like, and a standard method is provided for detecting trace mercury in water and atmosphere. The cold atom absorption and cold atom fluorescence method has high sensitivity, but is still influenced by matrix effect in high-salt environments such as seawater, so that detection is inaccurate, and salts such as sodium chloride with high concentration in the seawater can seriously interfere with signal stability of the cold atom absorption/fluorescence method, so that baseline drift, sensitivity reduction and even accurate quantification cannot be realized. Arsenic is an important environmental pollutant, the toxicity and migration transformation of which are closely related to morphology, with As (III) being the most toxic and As (V) being the second most toxic, organic arsenic being relatively weak. Arsenic pollution in groundwater, drinking water and part of soil and sediment is prominent, so it is important to establish an accurate detection method. The existing detection methods comprise a silver diethyl dithiocarbamate extraction spectrophotometry (HJ 694-2014) for measuring water quality arsenic, an atomic fluorescence spectrometry (HJ 694-2014 annex) for measuring water quality arsenic, a flame atomic absorption spectrometry (HJ 832-2017) for measuring soil quality arsenic and the like, and are widely used for conventional environment monitoring. At present, mercury and arsenic tests mainly adopt an atomic absorption method and an atomic fluorescence method, the methods can be analyzed by special instruments, the enrichment process is complicated, the recovery rate fluctuation is large, and the inductively coupled plasma mass spectrometry (ICP-MS) is commonly used for analyzing metal elements in water, but is easily interfered by matrix components such as salinity of a water body, particularly the measurement of trace elements such as arsenic and mercury, and the signal response of the method can be obviously influenced by the matrix of the water body. Because the interference of the sample matrix is serious in the analysis process, and the occurrence concentration of the substance to be detected in the actual sample is at trace or even ultra-trace level, the conventional analysis method has difficulty in meeting the accurate measurement requirement of the trace substance to be detected. Disclosure of Invention The invention aims to solve the technical problems and overcome the defects in the prior art, and provides the method and the device for simultaneously testing trace mercury and arsenic in water body by mass spectrometry, which have high sensitivity, low detection limit and difficult substrate interference. The method for simultaneously testing trace mercury and arsenic in water by mass spectrometry comprises the steps of placi