ABSTRACT
Objective:To establish a method for the content determination of total nitrogen in Nidus Vespae by salicylic acid and sodium hypochlorite spectrophotometry. Methods:The content of total nitrogen in Nidus Vespae from different areas with various batches was detected. Nidus Vespae was treated with sulfuric acid and hydrogen peroxide, and colored by salicylic acid and sodium hypochlo-rite. Using ammonium chloride as the control sample, the content of total nitrogen in the samples was tested at 650 nm. To ensure the method reliability, single factor experiments were performed to study the effects of temperature, reaction time and reagent dosage; or-thogonal experiments were used to screen optimum amounts of phosphate buffer solution, sodium salicylate solution and sodium hypo-chlorite solution. Results:The results showed that the optimum temperature was ambient, and the optimum time was 1. 5h. The opti-mum amount of phosphate buffer solution , sodium salicylate solution and sodium hypochlorite solution was 4 ml,7 ml and 1. 5 ml, re-spectively. The linear range of total nitrogen was 0. 06-0. 78 μg·ml-1(r=0. 9998), and the average recovery was 100. 98% (RSD=2. 10%,n=6). Conclusion:The method can be used to determine the total nitrogen content in Nidus Vespae. The total nitrogen content in Nidus Vespae is various in various areas with different batches.