Analysis of Urinary Calculi of Mixed and Unusual Composition: Raman Spectroscopic Investigation

Abstract

Raman spectroscopic analysis of kidney stones of mixed composition and of unusual stones is presented. Raman spectroscopy was used to analyze the chemical composition of kidney stones without extraction. A kidney stone sample was irradiated by laser light of 514.5 nm, and the scattered light was analyzed by a Raman spectrometer. The first stone was determined to be a mixture of calcium oxalate dihydrate and hydroxyapatite and the second one to be a mixture of calcium oxalate monohydrate, uric acid, and hydroxyapatite. The third and fourth stones were not mixed-composition stones, but rather stones with unusual composition. One was concluded to be carboxyapatite, and the other was mucoprotein-type stone. The present investigation indicates that Raman spectroscopy is a useful tool for direct analysis of kidney stone without going through the usual procedure of crushing, extracting, and carrying out tedious wet chemical analysis.