Objective To determine and validate the capacity of performing analysis of the laboratories in the disease prevention and control channel by effectively evaluating and monitoring their proficiency of detection techniques via intercomparison of these labs.
Methods The quantitative analysis of seven constituents of halohydrocarbons in household tap water was selected as the indices for this test. Two water samples for comparison, A and B, were analyzed by the participating labs separately. The results were statistically processed according to the intercomparison procedures specified in the National Standards:"Standard detection method for household drinking water:Specifications of organics" (GB/T 5750.8-2006) as well as the "Proficiency testing by interlaboratory comparisons——Part 1:Development and operation of proficiency testing schemes" (GB/T 15483.1-1999) and "Proficiency testing by interlaboratory comparisons——Part 2:Selection and use of proficiency testing schemes by lab oratory accreditation bodies" (GB/T 15483.2-1999).
Results Among the fifty one participating laboratories, fifty of them accomplished inter-laboratory comparison of results on seven analytes while one laboratory analyzed two analytes only, namely chloroform and carbon tetrachloride. The statistical results of this inter-laboratory comparison on analysis of halohydrocarbons in water samples showed that most robust coefficients of variance were below 10% and the average rate of satisfaction of the results was 77.3% (|Z| ≤ 2 results were satisfactory), while the average rate of unsatisfaction was 9.4% (2 <|Z|< 3 results were questionable). Among the seven constituents of halohydrocarbons analyzed, carbon tetrachloride had the highest rate (84.3%)of satisfaction, and dibromochloromethane had the lowest rate (70.0%)of satisfaction; whereas monobromo-dichloro-methane had the highest rate (22.0%) of unsatisfaction, and trichloroethylene had the lowest rate (6.0%) of unsatisfaction.
Conclusion The in tercomparison results of the analysis of halohydrocarbons in household drinking water by the participating labs demonstrated that the analysis capacities of these labs are basically controllable and comparable.
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