Objective To establish a method for melamine determination in human urine by liquid chromatographytandem mass spectrometry (LC-MS/MS).
Methods Urine samples were acidized with 0.2 mol/L hydrochloric acid, extracted in acetonitrile solution assisted with ultrasound, purified and concentrated using MCX solid phase extraction (SPE) column, and detected by LC-MS/MS in a 10 μL sample injection. The chromatographic conditions were as follows:Chromatographic column was CAPCELL PAK CR (SCX:C18=1:4); Mobile phase was a mixed solution (10 mmol/L) containing ammonium acetate, acetonitrile, and 0.1% formic acid that followed a volume fraction of 40:50:10; Column temperature was 30℃; Flow rate was 0.2 mL/min.
Results The retention time of melamine was 3.95 min. Melamine was linear in a range of 5-200 μg/L with a coefficient square (R2) value of 0.999 8. At the concentration of 10, 50, and 100 μg/L, the recoveries ranged from 96.7% to 97.2% with relative standard deviations≤5.16%. The limit of detection and limit of quantification were 0.6 μg/L and 2 μg/L, respectively.
Conclusion The method is featured by simple pretreatment and high sensitivity, which is suitable for detecting melamine in human urine.
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