Surface water is generally relatively clean. After 30 minutes of natural precipitation, taking the non precipitation part of the upper layer for analysis. If there are many suspended substances in the water sample or the color is darker, pretreat it by centrifugation, filtration or steam distillation. Using CIC-D120 ion chromatograph, SH-AC-3 anion column, 3.6 mM Na2CO3 + 4.5 mM NaHCO3 eluent and bipolar pulse conductance method,under the recommended chromatographic conditions,the chromatogram is as follows.
