Matrix Isolation Microsampling Procedures in Quantitative Fourier Transform Infrared Spectrometry

Abstract

Techniques for microsampling in infrared spectroscopy by matrix isolation are described. In the matrix isolation of liquid or solid compounds, the sample is vaporized and then diluted with a large excess of a matrix gas; the resulting gaseous mixture is deposited on a cold surface for spectroscopic examination as a solid. Detailed descriptions of the apparatus and procedures employed in the preparation of matrix-isolated samples for qualitative and quantitative analyses by Fourier transform infrared spectrometry are presented. Systems for “microsampling” (detection limits for specific compounds ∼0.5 to 1 μg) and “ultramicrosampling” (detection limits ∼50 to 100 ng) matrix isolation spectroscopy are described. Detection limits and Beer's law behavior for polycyclic aromatic hydrocarbons microsampled by matrix isolation are discussed. The advantages of matrix isolation as a technique for qualitative and quantitative infrared analysis of microsamples are itemized.