Spectrofluorimetric flow-injection method for the successive determination of chloroxine and chlorquinaldol in pharmaceutical preparations

A flow-injection method is proposed for the sequential determination of chloroxine (COX) and chlorquinaldol (CQD) at sub-μ ml−1 levels in mixtures. The method is based on the different behaviour of these analytes with metal ions. Aluminum(III) only reacts with COX to form a fluorescent complex, whereas cadmium(II) reacts with both analytes forming fluorescent complexes. The use of two sub-systems, through which aluminum or cadmium are pumped, makes it possible to obtain analytical signals due to the contributions of COX or COX plus CQD, respectively. The features of the method (linearity in the range 0.1–13 μg ml−1 RSD smaller than 2.5% in all instances and sampling frequency 30 h−1) and the results obtained on application to pharmaceutical preparations show its usefulness.