Studi Geseran Spektrum UV Senyawa Asam Barbiturat Pada Plat Al-TLC Si G 60 F254 Akibat Pengaruh Perbedaan pH Pengeluen Untuk Keperluan Uji Konfirmasi

The UV-spectra-shifting of allobarbital, barbital, butalbital and phenobarbital on AL-TLC-Si gel 60 F254 under exposed different pH eluent, drying TLC-plat at 110oC, and then plat placed at room temperature for more then 17 hours has been carried out. Spectra UV were read by using TLC-Scanner 3 –Camag-Muttenz- Switzerland between 190 and 300 nm. Aim of this research was to study UV-spectra-shifting which can conduct error by confirmation test using in situ UV spectra. There was no significant UV-spectra-shifting of barbiturate on TLC-plate after exposed by mobile phase: 10% HCl in methanol (pH=1), chloroform-acetone (80:20, v/v, pH=5), methanol-n-buthanol (60:40, v/v, pH=6), methanol-ammonia (100:1,5, v/v, pH=10) respectively. The significant shifting of UV spectra were obtained after TLC-plate exposed by cyclohexane-toluene-diethyl amine (75:15:10, v/v, pH=11) and 0,1 M KOH in methanol (pH=12), the spectrum shifting was 66% and 23% compared with spectra at pH=1. Drying of the TLCplates after exposed by mobile phase conducted no significant UV-spectra shifting, except after exposed by cyclohexane-toluene-diethyl amine (the shifting was 45%). Humidity absorption while placing the TLC-plates at room temperature for more then 17 hours after exposed by strong pH base lead the shifting UV-spectra of barbiturate to the weak base or neutral spectra. These shifting UV-spectra should be taken in consideration on confirmation test of barbiturate based TLC-UV in-situ spectra to reduce error.