A number of metabolic and environmental factors have been described as the causes of calculi formation in the urinary tract23. One approach to understanding these disorders, from which the patients suffer, is the analysis of chemical composition of the formed stones. Knowledge of urolith chemistry is a prerequisite underlying some effective treatment or measure to prevent recurrence9, 10. Numerous physical and chemical techniques have been used for the analysis of stone composition. Among them wet chemical analysis, the oldest technique, is still widely used due to its straight forward protocol and since it does not require expensive specialized equipments11. Unfortunately, chemical methods can only deter- mine redicals and ions, and therefore cannot differentiate between similar crystalline entities (e.g. uric acid vs. uric acid dihydrate or apatite vs. brushite or whewellite vs. weddellite). Furthermore, these methods require a relatively large quantity of test materials. Infrared (IR) spectroscopy is a technique for urolith analysis. Although there is a wide divergence of expert opinion on the value of IR spectroscopy for urolith analysis8, 27, some modern laboratories are now analyzing calculi by the IR spectroscopy rather than by the classical wet chemical techniques, 18, 27. The advantages of the IR spectroscopy are greater speed and specificity, uniform sensitivity to all components, and decreased quantities of test substances 1,5,18,29. The objective of this paper is to examine the chemical composition of urinary stones by IR spectroscopy.
