Characterization of Barbiturates by Infrared and Raman Microscopy

Abstract

There have been many studies involving spectroscopic characterization of barbiturates since the 1970s. Most studies focused on the spectral collection with a single instrument. Few explanations of the peak assignments, low frequency accuracy (2–4 cm⁻¹), and limited band investigation (<2000 cm⁻¹) were found in these studies. In this report, the latest infrared and confocal Raman microscopy techniques were employed to characterize and discriminate eight barbiturates, including barbital, phenobarbital, pentobarbital, amobarbital, secobarbital, butalbital, pentothal, and butabarbital. Good discrimination of these substances was achieved. The characteristic frequencies were summarized and tentatively assigned to the corresponding vibrations of the functional groups. These results are beneficial for the characterization of barbiturates in the forensic and pharmaceutical fields.

Keywords:

• Barbiturates
• Confocal raman microscopy
• Infrared microscopy

Acknowledgments

This study was financially supported by the State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (KF 2011-09).