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 + d imethylsulfoxide (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 o f the ethinyl group of ethinylestradiol to Ag via the sigma-pi type of bond is characterized by the band at 1971 cm(-1), acetylinic coordina tion by the band at 1805 cm(-1), and coordination via the ethinyl grou p rehybridized into sp(2) (C=C) by the band at 1558 cm(-1). By contras t, 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 dichloromet hane solution of ethinylestradiol. The SERS spectra of the Ag colloid/ (ethinylestradiol + dimethyl sulfoxide) system show a very strong char acteristic 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 ethi nyl-labeled estradiol.