ABSTRACT
Objective To identify the main compositions of urinary calculi found in pediatric patients who had the history of exposing to infant formula milk powder contaminated with melamine and try to find out the urinary calculus formation mechanism in these patients.Methods Sixteen patients were studied.These infant patients with urinary calculi due to consumption of melamine tainted milk powder had been admitted to hospital from June,2008 to August,2008.The components of the urinary calculi were separated by liquid chromatograph,and identified by electrospray ionization mass spectrometry,electron bombard ionization mass spectrometry,Fourier transform infrared spectroscopy,and quantitatively determined by liquid chromatograph.Results The main chemical components of the urinary ealculi were melamine and uric acid.The molar ratio of uric acid tO melamine was 2:1.Conclusion The main urinary calculus formation mechanism in infant patients who exposed to the inrant formula milk powder contaminated with melamine is melamine and uric acid formed indissoluble complex.