English abstract
A novel, rapid, selective, sensitive and environmentally friendly microfluidic method has been developed for the analysis of phenylephrine hydrochloride (PEH) and lisinopril (LIS). The method is based on the reaction of each analyte with tris (2, 2'-bipyridyl) -ruthenium(II) (Ru (bipy)3-) and peroxydisulphate in the presence of light to produce chemiluminescence (CL). It was observed that a pre-derivatization step is required to obtain analytically useful CL signal for the secondary amine in PEH, leading to a better sensitivity and lower detection limits. Therefore, a multifunction microdevice has been developed. The derivatization product and detection of the produced CL signal were all carried out in this multi-function microdevice. PEH was determined after derivatization with formaldehyde. In contrast, it was found that the secondary amine group in LIS gives a strong CL signal without the need for any pre-derivatization step. This is the first CL method reported for the analysis of LIS. Experimental factors that influence the derivatization reaction and the CL reaction were systematically optimized. Under the optimum condition, linear calibration curve between 0.25 – 15 ppm and 0.25 – 50 ppm for PEH and LIS were obtained. Such wide dynamic range has never been reported for the analysis of LIS. The detection limits were 0.027 ppm and 0.067 for PEH and LIS respectively. The determination of the CL signal by this new developed method exhibited no interference from various compounds, ions and any other ingredient which can be found in pharmaceutical formulations which is an indication that the proposed method is a stability indicating method. The number of samples which can be analysed in an hour by the proposed method reach 90 samples for PEH and 180 samples for LIS. The use of a multi-function microdevice enabled the development of a highly versatile analytical system that consumes minute amounts of reagents while preserving sensitivity. This procedure was successfully applied to the analysis of PEH and LIS in pharmaceutical formulations and biological fluids.
