固相萃取/高效液相色谱-串联质谱法测定黄瓜及土壤中的春雷霉素残留

Determination of Kasugamycin Residues in Cucumber and Soil by Solid Phase Extraction/High Performance Liquid Chromatography-Tandem Mass Spectrometry

建立了测定黄瓜和土壤中春雷霉素残留的固相萃取/高效液相色谱-串联质谱(SPE/HPLC-MS/MS)方法。黄瓜和土壤样品分别经1%甲酸的甲醇、0.5%甲酸水提取后,采用MCX固相萃取柱净化,以Waters Xbridge BEH Amide色谱柱分离,0.2%甲酸水-乙腈溶液进行梯度洗脱,电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测,基质匹配标准曲线外标法定量。该方法灵敏、准确、简单快速、重复性好,在2~250μg/L浓度范围内,不同基质中春雷霉素的线性相关系数均大于0.999,检出限为0.002 mg/kg,定量下限为0.008 mg/kg;在0.008、0.040、0.200、0.400 mg/kg 4个加标水平下,春雷霉素在黄瓜和土壤样品中的平均回收率为77.5%~97.0%,相对标准偏差为2.6%~10.7%,能够满足黄瓜及土壤中春雷霉素残留的检测需求。应用该法对田间样品进行检测,结果表明,春雷霉素在黄瓜中的残留量不超过0.053 mg/kg,小于我国规定的黄瓜中最大残留限量(0.2 mg/kg);土壤中春雷霉素的残留量不超过0.013 mg/kg。

A sensitive solid phase extraction/high performance liquid chromatography -tandem mass spectrometric （SPE/HPLC - MS/MS） method was developed for the determination of kasugamycin residues in cucumber and soil. The cucumber and soil samples were extracted with 1% formic acid methanol solution and 0. 5% formic acid water solution, respectively, and cleaned up with MCX sol- id phase extraction column, then separated on a Waters Xbridge BEH Amide column using acetoni- trile -0.2% formic acid as mobile phase by gradient elution. The qualitative and quantitative analy- ses were performed under positive electrospray ionization （ESI ＋ ） in multiple reaction monitoring （MRM） mode, with the matrix-matched calibrations. The calibration curves showed good linearities in the concentration range of 2 -250 μg/L with correlation coefficients more than 0. 999. The limits of detection（LOD） and the limits of quantitation（LOQs） were 0. 002 mg/kg and 0. 008 mg/kg, re- spectively. The average recoveries at four spiked levels （0. 008, 0. 040, 0. 200, 0. 400 mg/kg） were in the range of 77.5% - 97.0% for cucumber and soil, with relative standard deviations（ RS-Ds） of 2.6% -10.7%. The method is simple, rapid, sensitive, accurate and reproducible, and could meet the requirements for analysis of kasugamycin residues in cucumber and soil samples. The method was applied in the detection of the field samples, and the contents of kasugamycin residues in cucumber and soil were found not more than 0. 053 mg/kg and 0. 013 mg/kg, respectively, which were below the maximum residue limits（MRL） for kasugamycin in cucumbers defined by China（0. 2 mg/kg）.