Method for pretreating and measuring trivalent chromium ions and hexavalent chromium ions on line by ion chromatographic column switching method

Abstract

The invention discloses a novel method for pretreating and measuring trivalent chromium ions and hexavalent chromium ions on line by an ion chromatographic column switching method. A system comprises a sample injector, a six-way valve, a reversed-phase column, a six-way valve and column switcher, a receiving pipe, a negative ion separation column, a four-source gradient pump, a liquid conveying pump, a three-way joint, a derivative reaction pipe, an ultraviolet visible spectrophotometer, a waste liquid bottle and the like. The problems that two ions are separated through a special separation column and are respectively detected through a double-wavelength ultraviolet visible detector at present are solved, and the dependency of detection on instrument equipment is reduced; meanwhile, due to the application of an on-line pretreatment system, water-soluble organic matters are removed from a sample, labor consumption is reduced, the time for sample pretreatment is saved, and the complicated operation process is avoided.

Description

technical field [0001] The invention relates to an ion chromatographic circulating column switching system, in particular to a new method for determining trivalent chromium and hexavalent chromium ions by using an ion chromatographic column switching method for on-line pretreatment. Background technique [0002] Chromium exists widely in nature, usually in two forms of Cr(Ⅲ) and Cr(Ⅵ). The two have completely different properties. Among them, Cr(Ⅲ) is an essential trace element for the human body, while Cr(Ⅵ) has certain toxic and side effects on the human body, and even causes death in high concentrations [1]. For this reason, it is particularly important to develop methods for different valence states of chromium. [0003] At present, there are redox method, spectrophotometry, atomic absorption spectrometry and other detection methods for chromium in different valence states in the sample. Several methods are compared. The redox method is simple in principle and low in co...

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Problems solved by technology

[0003] At present, there are redox method, spectrophotometry, atomic absorption spectrometry and other detection methods for chromium in different valence states in the sample. Several methods are compared. The redox method is simple in principle and low in cost, but the reaction time is long, and the solution needs to be strictly controlled. Acidity prevents the mutual transformation of Cr(Ⅵ) and Cr(Ⅲ), which can easily make the detection results inaccura

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