Pretreatment method for mercury isotope determination of environmental sample

Abstract

The invention discloses a pretreatment method for mercury isotope determination of an environmental sample, which comprises the following steps: preparation before experiment, total mercury content test of the sample, instrument debugging before absorption, and sample absorption and recovery rate detection. According to the pretreatment method for measuring the mercury isotopes of the environmental sample, mercury in the environmental sample can be thermally reduced into Hg0 steam through a combustion furnace of a direct mercury measuring instrument (DMA-80); the sample enters the instrument and is firstly controllably dried, then the sample in a quartz tube is thermally decomposed by heating, and a decomposition product passes through a thermal decomposition catalytic bed for capturing halogen, nitrogen and sulfur oxides by virtue of continuous oxygen flow, a glass absorption device with a capillary tube is connected behind the DMA-80 detection device, mixed acid of hydrochloric acid and nitric acid is used for absorbing gold amalgam, pure mercury vapor brought out by oxygen flow is released through heating, the method can guarantee complete absorption and extraction of mercury in the sample, and the method can be applied to tens of ng / g to dozens of ng / g of environmental samples through multiple times of absorption.

Description

technical field [0001] The invention belongs to the technical field of mercury isotope determination, in particular to a pretreatment method for mercury isotope determination of environmental samples. Background technique [0002] With the development of multi-collection inductively coupled plasma mass spectrometry (MC-ICP-MS) and related technologies, MC-ICP-MS has become the standard for high-precision measurement of mercury (Hg) stable isotopes. Mass-dependent mercury isotope fractionation (MDF, expressed as δ 202 expressed in Hg) and mass non-mass fractionation (MIF, expressed in Δ 199 Hg expression) have about 10% variation. Mercury's MDF and MIF have been shown to be useful tracers for various natural and anthropogenic mercury sources and transformations. [0003] Traditional pretreatment methods for mercury isotope determination mainly use electric heating plates and microwave wet digestion to extract mercury elements from solid samples, which have the advantages o...

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Problems solved by technology

[0003] Traditional pretreatment methods for mercury isotope determination mainly use electric heating plates and microwave wet digestion to extract mercury elements from solid samples, which have the advantages of wide application and easy access to materials, but also have the disadvantage of being unable to effectively extract mercury from refractory components; in addition , mercury in environmental samples is generally at trace levels (<1-20ng / g), so a large number of samples need to be processed to obtain a mercury concentration that satisfies subsequent tests, which requires a large amount of acid to dissolve and other processing steps (centrifugation, filtration, Evaporation, etc.), many steps, time-consuming and labor-intensive, and increase the possibility of introducing other impurities in the treatment process, which will have a great impact on the mercury isotope test results