Attenuated total internal reflection microspectroscopy of isolated particles: An alternative approach to current methods

An alternative approach to conduct attenuated total internal reflection infrared microspectroscopy is described with the use of cartridge-based hemispherical internal reflection elements. The study demonstrates that the devices can be employed on any infrared microscope having reflectance capabilities. A comparison shows that the method provides the same signal-to-noise ratio in comparison to transmission studies for equal sample sizes. In addition, a 4x decrease in the sampled areas inherent with the method was verified for samples 60 mu m in diameter and larger. Examples are presented that demonstrate the method's capability of studying small isolated samples without the use of a contaminating mounting media. Examples are also presented that demonstrate the potential to study samples without the effects of diffraction.