Detection of nitritein in drinking water by high-throughput microplate method

Under strong acid conditions,diazo-coupling reactions between nitrite and m-phenylenediamine generate dzoic compound,which is an orange-red compound. Based on this principle,a high-throughput microplate method was established using microplate as the reaction vessel. To improve the sensitivity of this method,several experimental parameters were optimized. The results revealed that the optimum measurement wavelength was 451 nm,and using 30 g/L m-phenylenediamine(0.4 mol/L hydrochloric acid as the solvent)as the chromogenic agent,the reaction was complete within 10 min at room temperature. The detection limit was 0.017 mg/L,and linear range was 0~5 mg/L,with correlation coefficient value of 0.9997. Recoveries of nitrite from watsons distilled water were tested from 95.24% to 103.98%,with the coefficient of variation(CV)below 5%.This method was rapid,sensitive,easy to operate,and showed outstanding anti-interference ability,which was suitable for the screening of nitrite for a large number of drinking water samples.