BACKGROUND: Studies have shown that melamine may be associated with urolithiasis.
A more sensitive method is needed to analyze melamine in urinary stones to identify potential causes of urolithiasis.
METHODS: Here we compare the analytical methods of detecting melamine in urinary stones by Fourier transform infrared (FTIR) spectrophotometer and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in the laboratory and clinic. First, we established the melamine detection limit in melamine-cyanurate standard by the methods of FTIR spectrophotometer and MALDI-TOF MS. Subsequently, we applied these methods to 54 adult patients with upper urinary tract calcium urolithiasis.
RESULTS: The detection limit of melamine in melamine cyanurate standard by MALDI-TOF MS was ~10,000-fold more sensitive than FTIR. We applied both instruments to 54 stone specimens from 54 calcium urolithiasis patients. In those without distinctive melamine pattern in the FTIR spectra, melamine could be detected by MALDI-TOF MS in an additional 12 out of 42 subjects' stone specimens (28.6%). Compared to MALDI-TOF MS-negative subjects (n=30), those positive subjects (n=12) excreted significantly higher urinary melamine levels (P< 0.05).
CONCLUSIONS: Compared to FTIR, MALDI-TOF MS is a more sensitive method to detect the content of melamine in melamine-containing kidney stones.
Written by:
Wu CF, Liu CC, Chou YH, Shiea J, Shen JT, Wang SS, Wu MT. Are you the author?
Department of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Pingtung Hospital, Department of Health, Executive Yuan, Pingtung, Taiwan; Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan; Department of Urology, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Family Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Center of Environmental and Occupational Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
Reference: Clin Chim Acta. 2014 Feb 12. pii: S0009-8981(14)00027-8.
doi: 10.1016/j.cca.2014.01.010
PubMed Abstract
PMID: 24530299
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