Objective: To establish a high-performance liquid chromatography-mass spectrometry (LC/MS)-based method for efficient determination of melamine in urinary calculi in children taking melamine-contaminated formula milk powder.
Methods: LC/MS was employed to determine the contents of melamine in urinary calculi surgically removed from 17 children with a history of taking melamine-contaminated milk powder and in 4 samples of uric acid stone from adults. The positive ionization mode of electro-spray ionization source was used, and the limit of melamine determination was 0.1 mg/kg.
Results: No melamine was detected in the 4 uric acid stone samples from adults. Melamine was detected in 4 samples of urinary calculi from the 17 children, with the concentration ranging from 0.8 to 64 mg/lkg.
Conclusion: LC/MS is simple and effective for detecting melamine in urinary calculi, which is helpful to the treatment and follow-up.