Hasanin Tamer H A, Fujiwara Terufumi
Department of Chemistry, Faculty of Science, Minia University.
Department of Chemistry, Graduate School of Science, Hiroshima University.
Anal Sci. 2018;34(7):777-782. doi: 10.2116/analsci.17P571.
A highly sensitive flow-injection (FI) method was developed for the determination of ascorbic acid using chemiluminescence (CL) based detection. This method involved the following processes: (1) reduction of tetrachloroaurate(III) in hydrochloric acid with ascorbic acid; (2) on-line extraction of the residual Au(III) with rhodamine B from the aqueous hydrochloric acid solution into toluene, followed by the separation of the Au(III)-containing organic phase from the aqueous phase through a microporous Teflon membrane in the flow system; and (3) the measurement of CL produced in a flow cell upon mixing of the extract stream of Au(III) in toluene with luminol in the reversed micellar medium of cetyltrimethylammonium chloride-water in 1-hexanol-cyclohexane, which was injected into a CL reagent stream. In this procedure, a reduction in the CL intensity occurred due to the addition of ascorbic acid to the Au(III) solution. The CL signal of Au(III) decreased with increasing concentration of ascorbic acid in the aqueous sample solution. The proposed procedure allowed the indirect quantitative determination of ascorbic acid in the range of 1.0 × 10 to 1.0 × 10 M with a correlation coefficient of 0.987 and relative standard deviation of 2.1% (n = 6) at 1.0 × 10 M. The proposed FI-CL methodology was successfully applied for quantitative determination of ascorbic acid in fruit juices and pharmaceutical samples.
开发了一种高灵敏度的流动注射（FI）方法，用于基于化学发光（CL）检测来测定抗坏血酸。该方法包括以下过程：（1）抗坏血酸在盐酸中还原四氯金（III）；（2）用罗丹明B将残留的Au（III）从盐酸水溶液中在线萃取到甲苯中，然后在流动系统中通过微孔聚四氟乙烯膜将含Au（III）的有机相与水相分离；（3）在流动池中，将甲苯中Au（III）的萃取物流与十六烷基三甲基氯化铵 - 水在1 - 己醇 - 环己烷中的反胶束介质中的鲁米诺混合后，测量产生的化学发光，该混合液被注入化学发光试剂流中。在此过程中，由于向Au（III）溶液中加入抗坏血酸，化学发光强度降低。Au（III）的化学发光信号随水样溶液中抗坏血酸浓度的增加而降低。所提出的方法能够间接定量测定抗坏血酸，其浓度范围为1.0×10至此处原文有误，推测应为1.0×10⁻⁸ 1.0×10⁻⁸ M，在1.0×10⁻⁶ M时相关系数为0.987，相对标准偏差为2.
