Simultaneous determination of salicylamide and salsalate in serum and urine by first derivative variable-angle synchronous fluorescence spectrometry.

The determination of salicylamide and salsalate in human serum and urine is performed using a simple, rapid, sensitive, and selective method. The broad-band overlapping conventional spectra of both compounds are resolved by means of first derivative variable-angle synchronous fluorescence spectrometry. The method is based on the intrinsic fluorescence of both drugs in chloroformic solution. The measurements are performed in an alkaline medium, which is adjusted by adding 0.40 M pyrrolidine chloroformic solution to the organic phase. The method was applied for the simultaneous determination of salicylamide and salsalate, at concentrations between 0.100 and 1. 000 microg mL-1 for both components, by means of absolute values of a first derivative variable-angle synchronous scan at the emission/excitation wavelengths of 410/299 nm for salicylamide and 440/307 nm for salsalate. Serum and urine are extracted with chloroform, by adding acetate buffer solution to provide pH 4.8 in the aqueous phase. Finally, pyrrolidine chloroformic solution is added to organic phase, where both components are determined, without the need for a reextraction step to an aqueous phase.