Abstract:
Objective To explore the detection time limit of pH, chloroform, carbon tetrachloride, nitrate nitrogen and arsenic in tap water during the storage of samples under sealed cold and dark storage conditions.
Methods The residential building, administrative building and experimental building of a certain unit were selected as the sampling points of the tap water, and the samples were stored according to the corresponding method of the test items. During the study period, various indicators of the tap water were tested several times according to the Standard Test Method for Drinking Water (GB/T 5750-2006) and the test result were recorded, The data are analyzed by comparing the relative standard deviation of the test result.
Results The research on the end water samples preserved by corresponding method found that: The pH value of the tap water in the sealed brown bottle with cap was stable within 6 days, and the detected value of nitrate nitrogen was stable within 8 days (The protective agent is Sulfuric acid). The detection values of Chloroform and Carbon tetrachloride in the tap water sealed and refrigerated in the headspace bottle were stable within 30 days (The protective agent is Ascorbic acid), Under well-sealed refrigeration conditions with lidded polyethylene bottles and parafilm, the detection values were stable for 28 days when there were higher concentrations of arsenic in the terminal water (The protective agent is Sulfuric acid).
Conclusion Under a storage and transportation conditions(protective agent, sealed, dark and refrigerated), the detection time-limit of pH value, chloroform, carbon tetrachloride, nitrate nitrogen and arsenic in tap water can be appropriately extended.