Basic matters for the validation of environmental testing methods

2022-05-21 0 By

In order to meet the needs of more and more environmental pollutant detection, the updating speed of environmental detection methods is also accelerating. Both on-site detection and laboratory analysis methods need to be verified before they are used and qualified. Only after passing the test can they be qualified and reflected in the report.The following is a brief talk about the basic issues of environmental detection method verification.The first is to confirm the method detection limit and determination limit of the detection method.If the target object can be detected in the blank experiment, repeat the experiment for more than 7 times with the sample operation process, calculate the standard deviation and calculate the detection limit according to the formula.If the target object cannot be detected in the blank experiment, repeat the experiment for more than 7 times with samples 3-5 times of the estimated detection limit, calculate the standard deviation, and calculate the detection limit according to the formula.After the detection limit is confirmed, 4 times detection limit is generally used as the lower limit of the method.The second is to confirm the precision of the detection method.The experiment was repeated for more than 6 times with three concentrations of certified standard substances, and the mean value, standard deviation and relative standard deviation of each concentration sample were calculated.Then select the actual samples of 1-3 concentrations, repeat the experiment more than 6 times, calculate the average value of the determination of samples of each concentration, standard deviation and relative standard deviation and other parameters, if the actual samples of the required concentration can not be obtained, can use the way of adding standards for processing.Furthermore, it is necessary to confirm the accuracy of the detection method.The experiment was repeated more than 6 times with the same sample operation process using three concentrations of certified standard substances, and the relative errors of samples with different concentrations were calculated.Then select the actual samples with 1-3 concentrations, add the standard substance with 0.5-3 times of sample concentration, repeat the experiment for more than 6 times, calculate the spiked recovery rate of each concentration sample.Finally, according to the above results, confirm the number of valid data, summarize all data, prepare method verification report and keep the bottom for retrieval and reference.For more, check out Baby Wayne