Fourier Transform Infrared Analyses of Some Particulate Drug Mixtures Using a Diamond Anvil Cell with a Beam Condenser and an Infrared Microscope

Abstract

Although the diamond anvil cell (DAC) has been used in many forensic science laboratories for the analysis of trace evidence, few applications of this technique for the analysis of controlled substances have been reported. This may be due to both an unfamiliarity on the part of forensic drug chemists with this accessory and the nature and quality of spectra that result from use of a DAC on a dispersive instrument. Along with low energy throughput, which results in relatively high noise levels, strong broad diamond absorptions occur. With the use of a Fourier transform infrared instrument, these do not present a problem and nanogram quantities of materials can be analyzed when the DAC is used with an infrared microscope. Since single crystals can be sampled with the DAC, simple physical separations (involving particle-picking) can be used in certain cases to isolate drugs from particulate mixtures for infrared analysis. This method is especially useful for some “difficult” mixtures and residues, and several examples of such analyses involving samples of forensic science interest are presented.

Infrared Spectra of U.S. Automobile Original Finishes. VII. Extended Range FT‐IR and XRF Analyses of Inorganic Pigments In Situ—Nickel Titanate and Chrome Titanate

“…Spectra of all of the pigments were acquired using a single anvil (11,12) of a DAC mounted in the 5X beam condenser. The DAC is a specially‐designed version of the miniature diamond cell (High Pressure Diamond Optics, Tucson, AZ) constructed so that the beveled diamond edges are not included in the area encompassed by the apertures of the cell.…”