Are there suggestions to avoid contamination in phosphate testing?
Sample phosphate results are high, but the Hach standard runs correctly
Phosphate contamination can cause results to be unexpectedly high. This is most commonly caused by the detergent that is being used to clean lab glassware. Most detergents contain phosphate, which will adhere to the sides of glassware and can add a significant amount of phosphate to the test. Containers used for sample collection, storage and testing that have suspected contamination should be washed with a 1:1 HCl solution. Phosphate free detergents such as Liqui-nox (Product # 2088117 and 2088153) should be used for cleaning glassware.