Departamento de Quimica, Universidade Federal de São Carlos, P.O. Box 676, 13560-970 São Carlos, SP, Brazil.
Talanta. 2003 Jan 2;59(1):191-200. doi: 10.1016/s0039-9140(02)00477-0.
A multicommuted flow system is proposed for spectrophotometric determination of hydrosoluble vitamins (ascorbic acid, thiamine, riboflavine and pyridoxine) in pharmaceutical preparations. The flow manifold was designed with computer-controlled three-way solenoid valves for independent handling of sample and reagent solutions and a multi-channel spectrophotometer was employed for signal measurements. Periodic re-calibration as well as the standard addition method was implemented by using a single reference solution. Linear responses (r=0.999) were obtained for 0.500-10.0 mgl(-1) ascorbic acid, 2.00-50.0 mgl(-1) thiamine, 5.00-50.0 mgl(-1) riboflavine and 0.500-8.00 mgl(-1) pyridoxine. Detection limits were estimated as 0.08 mgl(-1) (0.5 mumoll(-1)) ascorbic acid, 0.8 mgl(-1) (2 mumoll(-1)) thiamine, 0.2 mgl(-1) (0.5 mumoll(-1)) riboflavine and 0.1 mgl(-1) (0.9 mumoll(-1)) pyridoxine at 99.7% confidence level. A mean sampling rate of 60 determinations per hour was achieved and coefficients of variation of 1% (n=20) were estimated for all species. The mean reagent consumption was 25-fold lower in relation to flow-based procedures with continuous reagent addition. Average recoveries between 95.6 and 100% were obtained for commercial pharmaceutical preparations. Results agreed with those obtained by reference methods at 95% confidence level. The flow system is suitable for application in quality control processes and in dissolution studies of vitamin tablets.
提出了一种多通流系统，用于分光光度法测定药物制剂中水溶性维生素（抗坏血酸、硫胺素、核黄素和吡哆醇）。流路是用计算机控制的三通电磁阀设计的，用于独立处理样品和试剂溶液，多通道分光光度计用于信号测量。通过使用单一参考溶液实现了定期重新校准和标准加入法。对于 0.500-10.0 mgl(-1) 的抗坏血酸、2.00-50.0 mgl(-1) 的硫胺素、5.00-50.0 mgl(-1) 的核黄素和 0.500-8.00 mgl(-1) 的吡哆醇，获得了线性响应（r=0.999）。检测限估计为 0.08 mgl(-1)（0.5 mumoll(-1))抗坏血酸、0.8 mgl(-1)（2 mumoll(-1))硫胺素、0.2 mgl(-1)（0.5 mumoll(-1))核黄素和 0.1 mgl(-1)（0.9 mumoll(-1))吡哆醇，置信水平为 99.7%。每小时可实现 60 次测定的平均采样率，对于所有物种，估计的变异系数为 1%（n=20）。与连续添加试剂的基于流动的程序相比，平均试剂消耗降低了 25 倍。对于商业药物制剂，平均回收率在 95.6%至 100%之间。在 95%置信水平下，结果与参考方法一致。该流系统适用于质量控制过程和维生素片剂的溶出研究。
