Rapid determination of NaNO2 content

The influencing factor of NaNO2 content in N-methyl-2-pyrrolidone (NMP) is analyzed by using N-(1-Naphthyl) ethylenediamine photometric means. The length of incidence wave of 540 nm is measured, the use of chromogenic solvent is 1.0 ml, pH of chromogenic reaction is more than 1.95 when the chromogenic reaction occurs. Study shows that some amount of NMP and NaNO3 in the chromogenic system have little influence on the chromogenic reaction. But corrosion products have greater interference on the determination of NaNO2, a pretreatment is conducted on a sample with aluminium hydroxide suspension, and error is less in sample testing after the treatment.