Instrument for synchronously characterizing soluble organic matter structure/physicochemical/concentration characteristics of water sample

Abstract

The invention relates to an instrument for synchronously characterizing soluble organic matter structure/physicochemical/concentration characteristics of a water sample, and belongs to the technical field of environment detection. All instruments are in single-flow-path connection, and the purpose is that (1) the synchronism and the stability of the whole multi-detector detection system are ensured; and (2) the influence of nitrate ions in the water sample to be detected is removed on the organic nitrogen distribution of the water sample to realize the accurate detection of the organic nitrogen distribution with different molecular weights. According to the invention, ultraviolet absorption/fluorescence characteristics/organic carbon concentration/organic nitrogen concentration of organicmatters with different molecular weights in the water sample can be synchronously detected, and the comprehensive characterization of the structure/physicochemical/concentration characteristics of thewater sample to be detected is realized. Rich quantitative/qualitative information provided by the instrument and the method can be used for research and application of rapid water quality scanning,accurate identification of drinking water disinfection by-product precursors, membrane pollution mechanism and water treatment process optimization and the like in the field of water treatment.

Description

technical field [0001] The present invention relates to the technical field of environmental detection, in particular to a single-channel UV / fluorescence / organic carbon / organic nitrogen multi-detector based on size exclusion chromatography to simultaneously characterize the structure / physicochemical / concentration characteristics of dissolved organic matter in water samples Instruments and methods. Background technique [0002] Dissolved organic matter (dissolved organic matter, DOM) widely exists in various natural water bodies, and it is one of the main concerns in drinking water treatment. The existence of DOM will make the water body show bad color and odor. In addition, DOM will also affect the treatment effect of ozone activated carbon and membrane filtration process, and may breed microorganisms in the water transmission and distribution network. DOM can also reduce the performance of oxidants and disinfectants, produce harmful oxidation and disinfection by-products,...

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Problems solved by technology

Patent CN201810480719.8 discloses an instrument and method for detecting dissolved organic nitrogen. Although the method can accurately detect the concentration distribution of DON with different molecular weights and avoid the influence of inorganic nitrogen ions such as nitrate on the detection results, the detection instrument It is more complicated, and more color reagents need to be added, which reduces the stability of the detection system and increases the analysis cost

[0005] For the combined detection of size exclusion chromatography and DOC and DON, the mainstream detection instrument in the world is the LC-OCD-OND system developed by the German DOC-Labor laboratory (that is, the combined size exclusion chromatography-organic carbon detector-organic nitrogen detector). system), the system reflects the water quality characteristics of the water sample by detecting the distribution of DOC and DON of different molecular weight components of the sample after separation by size exclusion chromatography. It is a milestone in water quality detection, but its shortcoming is : (1) using multi-flow path parallel mode to detect DOC and DON respectively has reduced the synchronism and the stability of multi-detector system; The current mainstream separation chromatographic column, because it is used in conjunction with the entire detection system, replacing the chromatographic column is equivalent to redesigning the entire separation and detection system) has a low separation limit (0.1-10KDa), and cannot separate macromolecular proteins and macromolecular polysaccharides. There is a literature "Three -dimensional excitation and emission matrix fluorescence (3DEEM) for quick and pseudo-quantitative determination of protein and humor-like substances in full-scale membrane bioreactor (MBR)" pointed out that due to the low separation limit of the chromatographic column and the interference of macromolecular polysaccharides, the use of this The correlation between the protein fluorescence obtained by the detection system and the protein fluorescence characterized by three-dimensional fluorescence is not good, which further shows that it cannot meet the current analysis requirements of heavily polluted surface water samples; (3) the detection system can only reflect the The structure/concentration information of dissolved organic matter is still lacking for the characterization of physical and chemical characteristics; (4) For the detection of DOC, the instrument uses an infrared carbon dioxide detector (NDIR) to detect the CO generated after the DOC is digested by ultraviolet light. 2 , and used nitrogen for CO 2 Blow off, the device occupies too much space, the operation is complicated, and it is very cumbersome. In addition, the detection limit of the NDIR detector is relatively high; (5) the system detects NO produced by DON through ultraviolet oxidation 3 - To characterize the DON concentration, this method is susceptible to the interference of inorganic nitrogen ions, and cannot accurately reflect the distribution information of DON with molecular weight; (6) Due to the monopoly position, the price of each equipment is extremely expensive

[0006] Patent CN201811466516.X discloses an organic nitrogen-organic carbon tandem online detection method and device. The device has the disadvantages of: (1) the thioproducts produced after activation of the pre-added oxidant (potassium persulfate) such as sulfuric acid ions, persulfate ions, etc. will absorb in the low ultraviolet wavelength region, which will have a greater impact on the subsequent DON detection results; (2) the higher content of nitrate in

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