How to verify the accuracy of the COD analyzer test results?

- Jul 24, 2020-

Under normal circumstances, the manufacturer of the cod analyzer will give a certain amount of cod standard solution when leaving the factory. At this time, the standard fluid has two functions. One is to train enterprise operators to use, and the other is to check the accuracy of the instrument. After the enterprise uses the cod detector for a period of time, the cod standard solution given by the manufacturer also expires. At this time, companies need to find another way. Companies can find cod detector manufacturers to re-purchase a certain amount of cod standard solution, or buy it from a nationally certified standard solution company. Enterprises with conditions can buy it themselves. Compiled according to relevant national standards.    

COD tester

Using COD standard solution, how to determine the accuracy of the COD detector test results?


First, companies can dilute the COD standard solution to different concentrations and then measure them separately to check whether the instrument is accurate. This method can test the full-scale accuracy of the instrument.


Second, the standard solution can be directly diluted to the data concentration value obtained from the newly determined water sample (approximately CAN), and then the test result is tested to see if the test result is consistent with the diluted concentration value. Due to human operation, it can be directly determined whether the detection value of the water sample is accurate. It is recommended to make several batches of samples for each batch, and then calculate the average value and compare it with the standard solution value. If the measured value is within the allowable error range, the instrument is accurate.    


Third, professional organizations please make inspection reports     

In order to judge the accuracy of the cod tester, the water sample can be sent to a third-party authoritative testing agency for testing on a regular basis, and then the testing data can be compared with the self-test data; the instrument can also be sent to the National Institute of Metrology for calibration, and the National Institute of Metrology will Issue a calibration report or test report for the enterprise. Of course, the cost of this method is high, and companies need to make their own decisions according to their needs. 

COD detector

Fourth, compare with titration method     

And compared with the national standard titration method to verify the accuracy of the measurement results of the COD detector