The determination of silicates in urinary calculi.

The determination of silica and silicates in urinary calculi is rendered difficult by the common occurrence in such material of high concentrations of calcium, magnesium and orthophosphate. The problem has been studied, and manual and semi-automated procedures for the determination are described. 145 stones from the urinary tracts of patients with spinal cord injury were analysed, but in all of them the silicon content was below the limit of detection of 0.7 gSiO2 per 100 g calculus.