水杨酸-次氯酸钠分光光度法测定露蜂房总氮含量

Determination of Total Nitrogen in Nidus Vespae by Salicylic Acid and Sodium Hypochlorite Spectrophotometry

目的:建立露蜂房药材总氮含量的水杨酸-次氯酸钠分光光度测定方法,考察其不同产地、不同批次药材的总氮含量。方法:露蜂房经硫酸-过氧化氢消化后,用水杨酸-次氯酸钠显色,以氯化铵为对照品在650 nm处测定总氮含量。为了确保检测方法的可靠性,对显色温度、时间、各试剂用量等做了单因素试验考察,并对磷酸缓冲液、水杨酸钠溶液和次氯酸钠溶液的用量进行了正交试验优化。结果:露蜂房总氮含量测定的显色温度宜为室温,反应时间宜为1.5 h,磷酸缓冲液、水杨酸钠溶液、次氯酸钠溶液的用量分别以4,7,1.5 ml为宜。在此条件下总氮浓度在0.06~0.78μg·ml^(-1)间与吸光度值呈良好线性关系(r=0.999 8),平均回收率为100.98%,RSD为2.10%(n=6)。结论:水杨酸-次氯酸钠分光光度法适用于露蜂房药材总氮含量测定;露蜂房药材总氮含量在不同产地、不同批次间存在着较大差异。

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 = 0.999 8）, 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.