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Instructions for testing paper for residual chlorine in water

by:BOQU     2023-03-29
[Introduction] Chlorine-containing preparations are the earliest and most widely used disinfectants for drinking water, which are of great significance to the implementation of disinfection and to ensure the disinfection effect. Available chlorine in drinking water chlorine preparations is a method to characterize the oxidation capacity of chlorine-containing disinfectants with chlorine gas as the standard. The higher the effective chlorine content in the disinfectant, the stronger the disinfection ability and the more thorough the killing of microorganisms. Residual chlorine refers to the residual chlorine content in water after the disinfectant has been used for a certain period of time. After the water is chlorinated and disinfected, if there is enough residual chlorine, it means that the disinfection effect is not only reliable, but also has a continuous disinfection effect. This speed test paper is a broad-spectrum chlorine test paper, which is used to judge whether the effective chlorine content in the disinfectant reaches the disinfection application value, whether the residual chlorine content in the water can ensure the disinfection effect, and whether the concentration meets the requirements. If it is too high, it will not affect the sensory properties of water, and may even cause secondary chemical pollution. [Detection principle] This rapid detection box adopts the principle of visual colorimetry for semi-quantitative detection. When the drug block on the test paper contacts with the sample, a color reaction occurs, and the color of the test paper is determined. Available chlorine and residual chlorine content in the sample. Attached document 'Bleach Powder and Bleach Powder Detergent Disinfectant Hygienic Quality Technical Specifications (Trial)' 'Hygienic Specifications for Catering Industry and Collective Catering Units' (Wei Jianfa [2005] No. 260) documents, the concentration of disinfectants and the methods of use are as follows: disinfection objects Available chlorine content mg/L Disinfection time minutes Usage method General object surface 25010~30 Wipe, rinse, soak, spray and disinfect the surface of various cleaning objects 50020~30 Wipe, rinse, soak, spray various non-clean objects Surfaces; wetting is appropriate for food and drinking utensils 250 20-30 Disinfection of eating utensils used by patients with non-communicable diseases; utensils used to remove residues, rinse then soak and sanitize; use potable water for residual disinfectant after disinfection Rinse clean 100030 eating and drinking utensils used by patients with infectious diseases; the residual disinfectant after disinfection should be rinsed with drinking water Fruits and vegetables 100~20010 Fruits and vegetables should be washed first and then disinfected; the residual disinfectant after disinfection should be rinsed with drinking water for fabrics 250 ~40020 When disinfecting, all fabrics should be soaked in disinfectant solution; net residual disinfectant drinking water should be crushed according to the amount of residual chlorine in the disinfected water ≥ 30 tablets before dissolving; add transparent liquid to water to eliminate toxins; effervescent Tablets can be directly added with water; after disinfection, the residual chlorine in the water should reach 0.3mg/L~0.5mg/L. According to the calculation of the amount of residual chlorine in the sewage, the residual chlorine in the sewage after disinfection should reach 4mg/L~6mg/L. Sewage discharge from medical institutions should meet the requirements of GB18446-2005 Excreta 10000~20000≥120 Stir evenly GB/T 5750.11-2006 Drinking water stipulates that the concentration of residual chlorine in plant water is [0.3,4] mg/L, drinking water at the end of the pipe network≥ 0.05mg/L, swimming pool water should be [0.2, 1.0] mg/L, pool feet should be soaked and disinfected. The water concentration should be [5, 10] mg/L. [Test steps] 1. Determination of available chlorine in disinfectant: Take 1ml of venom sample, add 4ml of water, shake well (the dilution factor is 5), immerse all the test paper in the sample solution, take it out immediately, wipe off the excess liquid on the edge of the test paper , place the test paper block horizontally, compare it with the color chart after 40 seconds, and read the result. When the color of the test paper is too deep and exceeds the range of the color card, the sample can be diluted for measurement; 2. Determination of residual chlorine in water: take an appropriate amount of sample in a clean and dry container, immerse the test paper in the sample solution and take it out immediately, wipe off the test paper If there is excess liquid on the edge, place the test strip horizontally with the test strip facing up. After 40 seconds, compare with the color card and read the result. [Result Judgment] 1. The available chlorine concentration value of the diluted sample is equal to the color card reading multiplied by the dilution ratio, and the residual chlorine concentration in the water is equal to the color card reading; 2. Comparing the detected value with the above standard, the available chlorine concentration is greater than or equal to the corresponding The required value for sanitized objects. If it is less than the required value, it is unqualified; if the drinking water meets the requirements of GB/T 5750.11-2006, it is qualified, and if it does not meet the requirements, it is unqualified.
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