Abstract: The surface-enhanced Raman (SER) spectra of stimulant drugs, including mefenorex, pentylenetetrazole, -amphetamine and pemoline, were obtained on colloidal silver. Silver colloids are prepared in a single step, at room temperature, by chemical reduction of Ag+ with sodium tetrahydroborate. Spectra are recorded using drug concentrations at the g mL-1 level. Individual drugs can be identified by characteristic vibrational bands. The SER spectrum of human urine and that of human urine spiked with mixtures of stimulant drugs are reported.

Abstract: A windowless flow cell was developed for detection by surface-enhanced Raman spectrometry (SERS) in FIA and LC. The flow cell consisted of two stainless-steel tubes (0.16 mm i.d.; 1.4 mm o.d.) mounted on an Al frame so that the ends were ~e;1.6 mm apart. The liquid draining from the upper to the lower tube was supported by surface tension and formed a column (1.4 mm diameter). The mobile phase from the FIA or LC was merged with a silver hydrosol stream then propelled in to the flow cell. The Raman spectra were recorded using a focussed Ar ion laser beam (488 nm; 85 mW) as the source. The performance of the flow cell was optimized using five drugs (amiloride, amiphenazole, 2-mercaptopyridine, pemoline and triamterene) as model analytes. The maximum SERS signal was obtained with flow rates of 0.075 ml/ml and 1.5 ml/ml for the mobile phase and silver hydrosol, respectively. The reproducibility (n = 5) of the FIA-SERS system for the determination of 625 ng amiloride was 1%.