Determination methods of nitrate and nitrite concentrations in whole saliva

Objective To compare three methods of examinating the concentrations of nitrate and nitrite in whole saliva and determine the best method for the determination.Methods Griess reaction, cadmium column reduction and high performance liquid chromatography (HPLC) were used to determine solutions containing standard analytical pure nitrate and nitrite of known concentrations and nitrate and nitrite levels of whole saliva samples obtained from ten volunteers. The sensibility of these three methods was compared.Results With Griess reaction and cadmium column reduction methods, the minimum nitrate and nitrite levels that could be tested were 10ng/μl and 1ng/μl respectively. The recovery rate of nitrite was 91.2%. With HPLC method, the minimum nitrate!and nitrite level was 0.8ng/μl and 0.1ng/μl respectively. The recovery rate of nitrite was 97.6%.Conclusion The sensitivity of HPLC was higher than that of Griess reaction and cadmium column reduction methods in determination of nitrate and nitrite in whole saliva.