A Systematic Evaluation of the Analysis of Drug Microcrystals Using Infrared Microspectroscopy

As submitted by the proposer: The ever evolving nature of the illicit drug market has not only posed significant analytical challenges but also created opportunities for development of new techniques and analytical approaches. The primary focus has been on confirmatory techniques. There is limited information available on the continued use of well-established screening techniques and their role in the analytical scheme. There is a need for rapid and more discriminatory preliminary techniques. We propose to address this need by conducting a systematic study of microcrystal tests for the new classes of drugs such as benzylpiperazines, pyrrolidophenones and beta keto amphetamines. This proposal creates an opportunity to understand the chemistry of microcrystal tests by combining the physical characteristics of crystals with their molecular information. Microcrystal tests have long been used successfully to identify some classes of drugs but have recently faced questions regarding the relative subjectivity associated with the identification of crystals. We propose that the combination of microcrystal tests and infrared microspectroscopy will be a mutually advantageous analytical process. The relative subjectivity associated with the identification of drugs using microcrystal tests can be mitigated when combined with the unique infrared spectrum of the crystal. The microcrystal tests in turn strengthen the application of infrared spectroscopy to drug mixtures. This combined technique has the potential to serve as a one-step process identification of controlled substances by SWGDRUG recommendations. It combines a category A and a category B technique in a rapid, cost-effective and sensitive analytical scheme. In this project we will first study the suitability of microcrystal tests to the above mentioned drug classes and document crystal characteristics with selected reagents. We will then use an FTIR microscope to analyze the microcrystals and compare the infrared spectra to the pure drug standard. The infrared spectra will be used to interpret the differences between crystals formed by closely related compounds or crystals with similar physical characteristics. The data generated will be in the form of photomicrographs of crystals and their corresponding infrared spectra. The data generated will be available for review and reproduction by other laboratories. Upon success of the initial studies we will implement this method for typical forensic drug samples to determine its applicability to casework and the potential for acceptance in court. ca/ncf