Diazotised p-Nitroaniline Reagent for the Determination of Trace Amounts of Salbutamol Sulphate in Aqueous Solution– Application to Pharmaceutical Preparations

A simple, rapid and sensitive spectrophotometric method for the determination of micro amounts of salbutamol sulphate in aqueous solution has been developed. The method is based on the coupling of salbutamol sulphate with diazotised p-nitroaniline in basic medium to form a coloured mono azo dye which is stable, water- soluble and exhibits maximum absorption at 488 nm. Beers law is obeyed over the range 10120 g of salbutamol sulphate in a final volume of 25 ml, i.e., 0.44.8 ppm with a molar absorptivity of 3.13104 l.mol.-1cm-1, a relative error of +1.80 to 3.40% and a relative standard deviation of +5.70 to +1.65%, depending on the concentration level. The proposed method does not require temperature control or solvent extraction and the method has been successfully applied to the determination of salbutamol sulphate in different types of pharmaceutical preparations, tablets and syrup.