Forensic medical diatom inspection method based on mixed acid digestion

Abstract

The invention discloses a forensic medical diatom inspection method based on mixed acid digestion. The forensic medical diatom inspection method comprises the steps of optical microscope inspection and scanning electron microscope inspection. The optical microscope inspection at least comprises the steps of: (1) performing a blank test; (2) performing mixed acid digestion by adding concentrated nitric acid, concentrated hydrochloric acid and a hydrogen peroxide solution in a sample to be tested and digesting in a manner of heating in water bath; (3) centrifuging and precipitating; (4) coating on a sheet and sealing by using epoxy resin; and (5) performing diatom qualitative and quantitative analysis. The scanning electron microscope inspection at least comprises the steps of: (1) performing a blank test; (2) performing mixed acid digestion by adding concentrated nitric acid, concentrated hydrochloric acid and a hydrogen peroxide solution in a sample to be tested and digesting in a manner of heating in water bath; (3) performing vacuum filtration; (4) automatically taking pictures and storing images by a scanning electron microscope; and (5) performing diatom qualitative and quantitative analysis. The forensic medical diatom inspection method based on the mixed acid digestion, disclosed by the invention, is high in sensitivity, efficient, safe, environment-friendly and exact in qualitative and quantitative analysis, and has good application prospect in the forensic medical drowning diagnosis practice.

Description

technical field [0001] The invention relates to the field of forensic medicine inspection, in particular to a forensic medicine diatom inspection method based on mixed acid digestion. Background technique [0002] The drowning diagnosis of decayed corpses in water is one of the biggest problems in the field of forensic science, and diatom detection has always been recognized as the best method. At present, there are many diatom detection methods reported in the literature, such as strong acid digestion method, ashing method, Soluene-350 digestion method, silica gel gradient centrifugation method, enzyme digestion method and PCR method, etc. [0003] Compared with other inspection methods, strong acid digestion has the advantages of short tissue digestion time, complete digestion, simple procedure, and low cost, so it is most commonly used in forensic practice. For example, in the GA / T 813-2008 standard ("Determination of Diatom Nitric Acid in Human Tissues and Organs"), con...

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Problems solved by technology

[0004] However, the shortcomings of the current strong acid digestion method are as follows: 1. The digestion process is violent, and there is a danger of burning the human body when strong acid is sprayed out, and it will damage the diatoms to a certain extent, resulting in the loss of diatoms; 2. The tissue demand and acid consumption Large amount, a large amount of strong acid and corrupt test materials in forensic practice release nitrogen dioxide and malodorous gas during the digestion process, which not only pollutes the environment but also leads to poor inspection working conditions; 3. The tissue digestion takes a long time and the work efficiency is low; 4. The digestion is not complete, and there are some tissue residues, oils, etc., which will affect the subsequent detection of diatoms