Method for measuring cadmium isotope ratio in rice by using multi-receiving inductance coupling plasma mass spectrum

Abstract

The invention provides a method for measuring a cadmium isotope ratio in rice by using a multi-receiving inductance coupling plasma mass spectrum. The method comprises the following steps: 1, performing microwave digestion on a rice sample to measure the content of total cadmium; 2, performing microwave digestion on the rice sample to measure the content of total cadmium in a separated and purified rice sample, thereby obtaining a separation and purification rate; 3, performing microwave digestion on a to-be-measured rice sample, and performing separation and purification to obtain to-be-measured liquid; and 4, measuring the cadmium isotope ratio in the to-be-measured liquid by using the multi-receiving inductance coupling plasma mass spectrum, wherein the separation and purification process specifically comprises the following steps: a, converting a nitric acid medium of a digestion solution into a hydrochloric acid medium; b, leaching the digestion solution of the hydrochloric acid medium for five times by using hydrochloric acid, and then leaching for two times by using Milli-Q water to obtain a leachate; c, eluting and collecting the leachate; and d, converting an eluting solution into a nitric acid medium from a hydrochloric acid medium. By adopting the method provided by the invention, the technical problem of separating and purifying cadmium from a rice sample low in cadmium content is solved, and a cadmium pollution source can be quickly and accurately restored, so that the method has a good application value.

Description

technical field [0001] The invention relates to a method for measuring cadmium isotope ratio in rice. More specifically, the present invention relates to a method for determining the cadmium isotope ratio in rice by multi-receiving inductively coupled plasma mass spectrometry Background technique [0002] Cadmium (Cadmium, Cd) is a heavy metal trace element with extremely high biological toxicity. It is a carcinogen (IARC, 1993) and a food pollutant (WHO, 1996). It is also one of the global pollutants. The chemical nature of cadmium is relatively active, and it is easily absorbed and transported by plants. In recent years, due to human activities, heavy metal pollution in farmland soil has become more and more serious, resulting in the problem of Cd pollution in food has become increasingly prominent. Compared with other crops, rice is easier to absorb and enrich cadmium, and does not show poisoning. According to the results of the 2002 national market rice safety spot ch...

AI Technical Summary

Problems solved by technology

Since the 1970s, cadmium isotope technology has been successfully applied to the study of the evolution of the material composition of the universe, the interaction between the lithosphere and the biosphere, the material cycle of the ocean system, and the upwelling process of seawater. However, due to the relatively low cadmium content in crops However, the mechanism of cadmium isotope fractionation in crops is not yet clear, leading to the fact that cadmium isotope technology has not been applied to the traceability of cadmium pollution in crops

[0004] At present, the research on the determination of cadmium isotope ratio is mainly focused on samples such as rocks, soil, seawater, and phytoplankton. For terrestrial plants, especially the determination of cadmium isotope ratio in samples with low cadmium content such as crops and agricultural products has not been reported. Limited application potential in traceability studies of crop cadmium pollution sources

At present, the reference standards used in the determination of cadmium isotope ratio include cadmium solution produced by Johnson Mattey Company (JMC), Spex Cd solution and BAM-I012Cd solution produced by Metuchen NJ USA, etc. Different scholars use the standards of their own laboratories to obtain cadmium isotope data, leading to incomparability of data from different laboratories

At present, the separation and purification process of cadmium in the sample is leached with different concentrations of hydrochloric acid, nitric acid, hydrobromic acid and other acids of various concentrations and types. The experimental operation process is complicated, time-consuming and acid-consuming.

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