Accurate determination method for chlorine, sulfur and organic carbon components in Xinjiang saline-alkali soil sample

Abstract

The invention discloses a method for accurately measuring chlorine, sulfur and organic carbon components in a Xinjiang saline-alkali soil sample. The method comprises the following steps: firstly, measuring the contents of Cl and S in batch samples by adopting an X-ray fluorescence spectrometry; determining to take the S measured value of the X fluorescence spectrometry according to the S content, or re-measuring by using the combustion iodometry; the organic carbon is determined by a potassium dichromate volumetric method or an infrared carbon-sulfur method according to the content of Cl in the sample. Aiming at the high-content element Cl in the soil in the Xinjiang saline-alkali area and the negative interference of the high-content element Cl on the detection result of sulfur and organic carbon, the detection method is combined and optimized, and the data detection accuracy and the working efficiency are improved.

Description

technical field [0001] The invention relates to the field of chemical investigation methods for soil samples, more particularly, to a method for accurate determination of chlorine, sulfur and organic carbon components in Xinjiang saline-alkali soil samples. Background technique [0002] Multi-target regional geochemical surveys belong to the scope of basic geological surveys. By collecting representative samples, using large-scale precision instruments, and using test methods with lower detection limits and higher precision, dozens of elements and more than ten kinds of elements are determined. A variety of organic matter indicators, providing high-precision, high-quality geochemical data. Draw various geochemical maps, find out the geochemical distribution and distribution characteristics of elements, verify the important anomalies found, and provide basic data for use in various fields. [0003] The soils in Xinjiang belong to the typical characteristics of elements in sa...

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Problems solved by technology

[0004] 1. When using X-ray fluorescence spectrometry to measure Cl, the spectrometer generally scans and measures elements in sequence. When chlorine is detected, X-rays have been irradiated for several minutes, and the Cl content tends to increase gradually with time. The reason should be In a vacuum state, the water in the sample will segregate to the surface, and the free Cl in the sample will migrate to the surface of the sample along with the water to increase the result. For example, drying the sample can avoid this problem, but drying the sample increases the possibility of contamination ; At the same time, the sample Cl content in this area is generally high, up to about 30%, far beyond the working curve

[0005] 2. In the determination of S by combustion iodometric method, it was found that the analysis results of many samples were seriously low and very unstable

The reason is that such samples contain a large amount of Cl, which cannot be absorbed by the absorption device in time, resulting in the 2 Substitution of I will cause negative interference to the reaction; at the same time, there is a large amount of sulfate in the sample, resulting in incomplete decomposition

[0006] 3. The sample analysis results were found to be seriously high in the determination of organic carbon by the potassium dichromate volumetric method. The reason is that this type of sample contains a large amount of Cl. Since chloride can also be oxidized by potassium dichromate, it will make the organic carbon result higher

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