很少有人做兒童的尿液三聚氰胺（MEL）的分析。在這項研究中，我們開發同位素液相層析串聯質譜儀的方法檢驗尿液中之三聚氰胺。該方法過程包括酸化、固相萃取和液相層析串聯質譜儀分析。13C3N3（15NH2）3作為內部標準的校正。過渡離子 m / z 127> 85, m / z 133> 89, 和 m / z 127> 68被用於三聚氰胺之定量確認。我們對恢復率和精確度進行了評估，以保證該方法的適用性。量化的極限（定量限）為 0.01微克/毫升，而計算方法的檢出下限為 0.006微克/毫升。平均回收率為 96至99％。此方法適用於篩檢三聚氰胺毒奶製品與兒童尿液樣本。我們進行病例對照研究，先選擇了10位腎結石案例和20位年齡和性別匹配的對照。結果發現，在10位三聚氰胺濃度升高者中，有三例腎結石。相比之下，20位年齡和性別匹配飲用台灣品牌奶粉的非腎結石對照者都顯示三聚氰胺濃度低於檢測限，除了兩個孩子濃度在背景值0.02μg/ml外。此項研究用液相層析串聯質譜儀分析，建立了兒童尿液樣本背景值。檢驗結果顯示尿液三聚氰胺濃度與這些人之腎結石有高度相關性。由此研究得知測量尿液三聚氰胺濃度可有助於確診三聚氰胺有關之腎結石，但其臨床應用的需要進一步探討。
Little is known about melamine (MEL) analysis in children’s urine. In this study, an isotopic ultra performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) method was developed and systematically validated for analyzing MEL in urine. The method is easily performed and comprises acidification, solid phase extraction (SEP) and UPLC/MS/MS analysis. 13C3N3(15NH2)3 was used as the internal standard (IS) for calibration. Transition ions m/z 127 > 85 of MEL and m/z 133 > 89 of IS were used for quantification and m/z 127 > 68 of MEL was used for quantitative confirmation. Recovery and precision were assessed to guarantee the applicability of the method. The limit of quantification (LOQ) was 0.01 &；micro；g/mL while the calculated method detection limit was 0.006 &；micro；g/mL. The mean recoveries ranged from 96 to 99%. The method was then applied to analyze urine samples from children with potential MEL-tainted dairy products consumption during screening in Taiwan. Ten nephrolithiasis cases and 20 age- and gender- matched controls were selected for this study. Three out of the 10 nephrolithiasis cases had elevated levels of MEL. Comparatively, twenty age- and gender-matched non-nephrolithiasis controls consuming Taiwan brand milk powder all showed MEL levels lower than the detection limit except for two children with background levels of 0.02&；micro；g/mL. The background level in these children urine samples was established by UPLC/MS/MS analysis. Positive results of urine MEL tests might be associated with nephrolithiasis in these candidates. Measurement of urine MEL concentration can be helpful in confirming MEL related nephrolithiasis, but its clinical application needs further clarification.
