固相萃取-同位素稀释高分辨质谱法测定苹果及橙柑类水果中吗啉残留

Determination of morpholine in apples and citrus by solid phase extraction-high resolution mass spectrometry with isotope dilution technique

目的 建立固相萃取结合高效液相色谱-四级杆/静电场轨道阱高分辨质谱的检测方法分析苹果和橙柑类水果中吗啉的残留情况。方法 样品采用含1%甲酸的乙腈-水溶液（1：1,V/V）提取,经MCX固相萃取柱净化,BEH HILIC色谱柱分离,以含0.1%甲酸的乙腈、含0.1%甲酸和4 mmol/L甲酸铵的水溶液作为流动相进行梯度洗脱分离。采用正离子采集模式对样品进行分析,t MSMS采集模式定量分析,内标法测定。结果 吗啉在1~100μg/L范围内呈良好的线性关系,回归系数r2〉0.999,该方法的检出限和定量限分别为5和10μg/kg。在不同加标水平下的平均回收率为81.3%~103.7%,日内和日间精密度分别为2.7%~7.4%和1.7%~8.1%。结论 本方法灵敏、准确,适用于苹果和橙柑类水果中吗啉残留的分析测定,具有很好的实际应用价值。

Objective To establish a solid phase extraction （SPE） /high-resolution benchtop Q exactive mass spectrometry （HRMS） method for the analysis of morpholine in apples and citrus. Methods The samples were first extracted with 1% formic acid in acetonitrile-water （1 ： 1, V/V） and then cleaned up using SPE procedure. The chromatographic analysis was performed on a BEH HILIC column with 0. 1% formic acid and 4 mmol/L ammonium formate in water/acetonitrile as the mobile phase with gradient elution. The internal standard calibration was used for quantification. Results The linearity was satisfying within 1-100 μg/L, and the coefficients of determination （r2） were above 0. 999 for morpholine. The limit of detection （LOD） and the limit of quantitation （LOQ） were 5 and 10 μg/kg, respectively. The recoveries of the spiked apples and citrus samples at the levels of 10, 20, and 100 μg/kg ranged from 81.3% -103.7% , with intra-day repeatability and inter-day reproducibility precision 2.7% -7.4% and 1.7%-8.1% , respectively. Conclusion The method was sensitive and accurate, and was suitable for the analysis of morpholine in apples and citrus.