SURFACE-ENHANCED RAMAN-SCATTERING SPECTROSCOPIC STUDY OF 17-ALPHA-ETHINYLESTRADIOL ON SILVER COLLOID AND IN GLASS-DEPOSITED AG-17-ALPHA-ETHINYLESTRADIOL FILM

The SERS spectra of ethinyl-labeled estradiol (17 alpha-ethinyl-1,3,5[10]-estratriene-3,17 beta-diol) have been investigated for both glass-deposited Ag-ethinylestradiol films originating from the corresponding metal liquidlike films (MELLFs) and a Ag colloid/ethinylestradiol + dimethylsulfoxide (solvent) SERS-active system. The SERS spectra of the glass-deposited, interfacial Ag-17 alpha-ethinylestradiol films show the presence of three forms of coordinated ethinylestradiol. Bonding of the ethinyl group of ethinylestradiol to Ag via the sigma-pi type of bond is characterized by the band at 1971 cm(-1), acetylinic coordination by the band at 1805 cm(-1), and coordination via the ethinyl group rehybridized into sp(2) (C=C) by the band at 1558 cm(-1). By contrast, only the latter type of coordination of the ethinyl group to Ag was identified for the same film after dipping for 1 h into a dichloromethane solution of ethinylestradiol. The SERS spectra of the Ag colloid/(ethinylestradiol + dimethyl sulfoxide) system show a very strong characteristic marker band at 1810 cm(-1) attributed to the ethinyl group chemisorbed by an acetylinic type of coordination. This system appears to be suitable for the selective SERS spectroscopic detection of ethinyl-labeled estradiol.