Spectrofluorimetric Determination of Methyl Paraben in Pharmaceutical Preparations by Means of its Dansyl Chloride Derivative

 A spectrofluorimetric method for the determination of methyl paraben based on derivatization with the labelling reagent dansyl chloride (DNS-Cl), is presented. The effect of the reaction variables (pH, DNS-Cl concentration, temperature, reaction time) and instrumental parameters, has been examined. A linear calibration graph in the ng/ml range has been established. The limit of detection is 18 ng/ml with relative standard deviation less than 3%. The proposed method has been satisfactorily applied to determination of the paraben in two pharmaceutical preparations. Received May 25, 1999. Revision October 20, 1999.