荧光猝灭法测定中草药中痕量钴

Fluorospectrophotometric Determination of Trace Amount of Cobalt in TCM

摘要: 在pH 7.4的磷酸盐缓冲溶液和十六烷基三甲基溴化铵(CTMAB)介质中,钙黄绿素与罗丹明B之间发生能量转移而导致后者的荧光增强(λem 581 nm)。当在此体系中加入痕量Co2+后,于发射波长581 nm处产生荧光猝灭现象。据此提出了荧光猝灭法测定中草药中痕量钴含量。Co2+的质量浓度在4.0×10-4~1.35×10-2g·L-1范围内与反应液荧光强度的降低程度呈线性关系,方法的检出限(3S/N)为1.8×10-7g·L-1。方法用于中草药样品分析,回收率在97.6%~102%之间,测定值的相对标准偏差(n=6)在0.98%~1.5%之间。

Abstract: In a PBS of pH 7.4 and in the presence of CTMAB, reaction of energy transfer between rhodamine B and calcein occurred as observed by the enhancement of fluorescence intensity at the λem of 581 nm. When microamount of Co2+ was added to this reaction system, significant decrease in fluorescence intensity at this wavelength was observed. Based on these facts, a method for the determination of trace amount of Co2+ by fluorospectrophotometry was proposed. Linear relationship between the magnitude of decrease in fluorescence intensity and mass concentration of Co2+ was obtained in the range of 4.0×10-4-1.35×10-2g·L-1, with detection limit (3S/N) of 1.8×10-7g·L-1. The proposed method was used to the analysis of TCM, giving values of recovery and RSD′s (n=6) in ranges of 97.6%-102% and 0.98%-1.5% respectively.