Diffuse reflectance technique for infrared analysis of urinary calculi.

We investigated the application of diffuse reflectance infrared Fourier transform spectroscopy to analysis of urinary calculi and compared its operation with that of older sampling techniques (pellet, mull, and attenuated total reflectance). The new method requires shorter sample preparation time and less sample (30 micrograms). Quantitative measurements are easier. Because of the additivity of the Kubelka-Munk functions, a quasi-exhaustive collection of infrared spectra of mixtures of possible components of stones can be compiled, facilitating a computerized intrepretation of infrared spectra of urinary calculi.