酸性染料比色法测定苦木注射液总生物碱含量

Quantitative Determination of Total Alkaloids in Kumu Injection by Acid Dye Colorimetry

本研究旨在建立一种适用于测定苦木注射液中总生物碱舍量的酸性染料比色法,以替代现行部颁标准的重量法.以苦木注射液中含量最高的铁屎米酮型生物碱苦木酮碱(4-甲氧基-5羟基铁屎米酮,C_(15)H_(10)N_2O_3)为对照,以溴甲酚绿为酸性染料,在pH值为5.0的缓冲液中与生物碱生成有色离子对,以氯仿萃取,在420 nm处测定吸光度,根据供试与对照的吸光度比值计算供试品的总生物碱含量.苦木酮碱在10.0~49.8μg/mL浓度范围内与吸光度呈良好线性关系,回归方程为A=0.011 7C+0.169 2(r=0.993 3),平均回收率99.1%,相对标准偏差(RSD)1.4%(n=9);该方法对10批苦木注射液总生物碱含量测定的结果与重量法无显著性差异(P=0.82).该方法具有灵敏度高、选择性好、易于重现的优点,适于替代现行重量法应用于苦木注射液的总生物碱含量测定.

The present study aims to develop an acid dye colorimetry method for quantitative determination of total alkaloids in Kumu injection to replace the current gravimetric assay. Nigakinone （4-methoxy-5-hydroxycanthin-6-one, C15H10N2O3） , one of the most abundant alkaloids in Kumu injection was used as reference control. Alkaloids combine with the acid dye bromocresol green in buffer solution with pH value of 5.0. The resulting ion-pair product is extracted into chloroform, and the absorbance at 420 nm is detected with the reagent as blank control. Then the content of total alkaloids is calculated according to the absorbance ratio to that of reference control. The linear range is 10.0 -49. 8 μg/mL for alkaloids calculated as nigakinone with a typical regression equation of A =0. 011 7C ＋ 0. 169 2 （r =0. 993 3）, the average recovery of 99. 1%, and the relative standard deviation （RSD） of 1.4% （n = 9）, Ten batches of Kumu injection samples are detected by both the present method and gravimetrie method, and there is no significant difference between the results from the two methods according to paired t-test （p = 0. 82）. All the findings indicate that the present acid dye eolorimetric method can meet the requirements of speci- ficity, sensitivity, accuracy and reproducibility, thus offer a satisfactory alternative for quantitation of total alkaloids in Kumu injection.