Evaluation of the Performance of Laboratories for Chemical Analysis
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Date
2011-02-07
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Bulletin of the Department of Medical Sciences - วารสารกรมวิทยาศาสตร์การแพทย์
Abstract
The quality of drinking water is very important to health, analysis for quality and safety is, there, important in order to obtain the results that are accurate and accurate and reliable. Science there are a vast number of laboratories distributing country wide that are capable of analysis of water including drinking water, in 2007, the Bureau of Quality and Safety of Food, Department of Medical Sciences, conducted a program to evaluate the competence of laboratories in determining pH, solids, total hardness, chloride, fluoride nitrate and sulfate in water. In this study, portions of homogeneous water sample were distributed to participating laboratories to be analyzed. Then the analytical results from laboratories were analyzed and evaluated statistically. The value of z-score was used to evaluate the competence of the individual laboratories. There were 45 laboratories involved in this study. Among these, 26 laboratories submitted 1-6 test results and 19 laboratories submitted the results of all tests, 8 of which reported all 7 results that are satisfactory. It was found that the percentage of laboratories that reported the satisfactory results for pH, total solids, total hardness, chloride, fluoride, nitrate and sulfate from 43, 40, 40, 39, 28, 31 and 28 laboratories were 90.7, 85.0, 80.0, 76.9,89.3, 87.1 and 85.7 respectively, questionable results were 0, 10.0, 5.0, 7.7, 3.6, and 10.7 respectively, unsatisfactory results were 9.3, 5.0, 15.4, 7.1, 9.7 and 3.4 respectively. The results that are questionable or unsatisfactory might be caused by, for example, inappropriate chemical and regents, malfunctioning instrument, deviation from the procedure, transfer of data, reporting the wrong result. It is recommended that laboratories investigate the sources of problems and implement corrective action to prevent the recurring of problems and to improve the performance. In conclusion, most of participating laboratories were competent in analyzing water samples. Moreover from this study, individual laboratories could compare itself with other laboratories. However, in order to predict the long term performance, more data from further studies are neededKey words : laboratories performance, drinking water, inter laboratory comparison,
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Bulletin of the Department of Medical Sciences - วารสารกรมวิทยาศาสตร์การแพทย์; Vol.51 No.2 April - June 2009; 154-169