Detection of sulfonamide drug in urine using liquid-liquid extraction and surface-enhanced Raman spectroscopy

In this article we have applied liquid-liquid extraction (LLE) as a sample preparation technique for detection of sulfadimethoxine (one of sulfonamide drugs) in urine using surface-enhanced Raman spectroscopy (SERS). SERS substrate based on silver nanoparticles has been prepared by citrate reduction of silver nitrate. Obtained calibration curve (SERS intensity vs. sulfadimethoxine concentration) has been used for detection of sulfadimethoxine in human urine samples artificially contaminated by sulfadimethoxine. Three different solvents (ethyl acetate, diethyl ether, chloroform) have been used for LLE performance tests. Chloroform being found as the most effective one based on calculation of recoveries after SERS measurements. Thus we would like to propose fast (less than 20 minutes), simple and sensitive (detection limit up to 1 μg/ml) test for detecting sulfa drugs in urine using a combination of SERS with LLE with sample volume as low as 100 μL. Such test can be applied for evaluation of the degree of drug extraction from human body and half-life of such drug applied in the course of therapeutic treatments of certain diseases.