The Property Value Comparison of Permanganate Index and Ammonia Nitrogen Reference Materials for Environmental Monitoring
This study investigated the manufacturers,concentration levels and usage of the reference materials permanganate index(CODMn)and ammonia nitrogen(NH3-N)for environmental monitoring.According to the survey results,7 commonly used brands of CODMn liquid standard and 9 commonly used brands of NH3-N liquid standard were selected to carry out the property value comparison and quality evaluation research.129 liquid standards were anonymously purchased and measured by the recommended standard of GB 3838-2002 after recoded.The uncertainty of determination results was calculated and evaluated,and the En value method was used for comparison and evaluation.The research showed that the property value of NH3-N standard were all satisfied,the capping operation in CODMn test would cause the measurement results to be higher.If the pre-treatment test unfollowed the requirement of the standard label certificate,it would cause the deviation of the test result and finally affect the evaluation result.It was suggested that the monitoring personnel should rationally select and standardize the use of environmental liquid standards,strengthen the selection and management of environmental liquid standards to ensure the effective control of the testing process.
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