title: [Determination of melamine by high-performance liquid chromatography-mass spectrometry in urinary calculi].
abstract: 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.
  
  
  CONCLUSIONS
  LC/MS is simple and effective for detecting melamine in urinary calculi, which is helpful to the treatment and follow-up.
authors.affiliation: Department of Urology, Minimally Invasive Surgery Center, Guangzhou Medical College, Guangzhou, China. wwqwml@163.com
authors.forename: Wenqi
authors.initials: W
authors.lastname: Wu
authors.forename: Luping
authors.initials: L
authors.lastname: Wang
authors.forename: Lili
authors.initials: L
authors.lastname: Ou
authors.forename: Yeping
authors.initials: Y
authors.lastname: Liang
authors.forename: Zanlin
authors.initials: Z
authors.lastname: Mai
authors.forename: Shujue
authors.initials: S
authors.lastname: Li
authors.forename: Chichang
authors.initials: C
authors.lastname: Shan
authors.forename: Jian
authors.initials: J
authors.lastname: Yuan
authors.forename: Guohua
authors.initials: G
authors.lastname: Zeng
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003611:Dairy Products / Q000009:adverse effects; D005260:Female; D005506:Food Contamination; D006801:Humans; D007223:Infant; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D014227:Triazines / Q000032:analysis*; D014545:Urinary Calculi / Q000139:chemically induced / Q000737:chemistry*
chemical_list: D014227:Triazines; C011907:melamine