Rapid analysis method for trichloronitromethane as disinfection by-product in drinking water

Abstract

The invention relates to a method for quickly analyzing trichloronitromethane as a disinfection by-product in drinking water, which comprises steps of sample pretreatment, instrument condition control and running measurement; during the sample pretreatment, adjusting pH to range from 4.5 to 5.5; adopting ascorbic acid and ammonium chloride as a chlorination reaction termination agent to facilitate stabilization of the trichloronitromethane; and adopting methyl tertiary butyl ether or ethyl acetate as an extracting agent. The instrument condition control comprises adopting a gas chromatography-mass spectrometer as a main instrument for detecting the trichloronitromethane; controlling the sample feeding amount at 3muL; and controlling the temperature of an introduction port to between 105 and 115 DEG C. The method has the following beneficial effects of reducing loss of the trichloronitromethane greatly, improving reclaiming rate and enrichment multiple of the trichloronitromethane, andrevealing stability of the trichloronitromethane under different pH conditions and effect of different common chlorination reaction termination agents on the trichloronitromethane.

Description

technical field [0001] The invention belongs to the field of municipal water supply and drainage and environmental engineering, and relates to water quality analysis technology, especially a rapid analysis method for disinfection by-products in drinking water. Background technique [0002] Disinfection of drinking water began in the early 19th century. At that time, chlorine was used as a disinfectant. It can effectively kill microbial pathogens in water and greatly reduce the chance of people dying from water-borne diseases such as dysentery and cholera caused by drinking water. A major breakthrough in the history of health. However, drinking water disinfection has two sides. While improving water quality and eliminating aquatic diseases, it also produces a series of disinfection by-products (Disinfection by-products, DBPs) that are harmful to humans. Disinfection by-products of drinking water refer to compounds produced by the reaction of disinfectants used for drinking w...

AI Technical Summary

Problems solved by technology

[0005] 1. Inherent problems of the electron capture detector (ECD): chloropicrin is unstable, and when it passes through the electron capture detector (ECD), it is easy to be thermally decomposed, resulting in the loss of chloropicrin, and the instrument response value (peak area) The lower the detection limit, the lower the accuracy;

[0006] 2. The inherent problem of extraction, foreign countries generally adopt direct liquid-liquid extraction (LLE) method to enrich the trichloropicrin in the water sample, the recovery rate is low, and the trichloropicrin in the drinking water is in μ g / The level of L, resulting in poor recovery and accuracy of the analytical method;

[0007] 3. In the process of studying the formation mechanism and control methods of disinfection by-products (DBPs), it is often necessary to carry out isotope calibration and product analysis. The above tasks cannot be completed by gas chromatography / electron capture detector (GC / ECD). Only through gas chromatography / mass spectrometry (GC / MS) can only be achieved;

[0008] 4. Chloroprin is not absolutely stable in water;

[0009] 5. Drinking water contains 0.05-4.0 mg / L residual chlorine (Cl 2 ), which needs to be eliminated to avoid its influence on chloropicrin (Cl 2 Oxidation of chloropicrin), it is necessary to add a chlorination reaction terminator to eliminate residual chlorine and terminate the chlorination reaction, however, the terminator may also have an impact on chloropicrin in the chlorination reaction

Images