超高效液相色谱-串联质谱法测定葵花籽中4种交链孢霉毒素的含量

Determination of 4 Alternaria Mycotoxins in Sunflower Seeds by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

取2.5g已粉碎的葵花籽样品,加入500.0μL含100.0μg·L^(-1)交链孢酚单甲醚-d_(3)(AME-d_(3))、1000.0μg·L^(-1)滕毒素-d_(3)(TEN-d_(3))和交链孢酚-d_(2)(AOH-d_(2))、5000.0μg·L^(-1)细交链孢菌酮酸-d_(13)(TeA-d_(13))的混合内标溶液,混匀,放置过夜,用25.0mL体积比为45∶10∶45的乙腈-甲醇-0.05mol·L^(-1)磷酸二氢钠溶液(pH 3.0)混合液振荡提取,离心。取上清液,用水定容至30.0mL,分取6.0mL,加入15.0mL 0.05mol·L^(-1)磷酸二氢钠溶液(pH 3.0),过Waters Oasis HLB固相萃取柱(预先用5.0mL甲醇和5.0mL水活化),用20%(体积分数)甲醇溶液淋洗,抽干固相萃取柱,用10mL体积比为1∶1的含1%(体积分数)氨水的甲醇-乙腈混合液进行洗脱。将洗脱液于40℃氮吹至近干,残渣用200.0μL甲醇复溶,并用水定容至2.0mL,所得溶液采用超高效液相色谱-串联质谱法测定其中交链孢酚(AOH)、交链孢酚单甲醚(AME)、细交链孢菌酮酸(TeA)和腾毒素(TEN)等4种交链孢霉毒素的含量,内标法定量。结果表明,Waters Oasis HLB固相萃取柱净化效果最佳,在洗脱剂中加入氨水有利于改善峰形,基线更平滑;4种交链孢霉毒素的质量浓度在一定范围内与对应的峰面积和内标峰面积的比值呈线性关系,测定下限(10S/N)为0.15~1.50μg·kg^(-1)。按照标准加入法进行回收试验,回收率为75.0%~112%。对实际样品做7组平行,测定值的相对标准偏差均小于13%。方法用于实际样品分析,结果显示检出率和检出量最高的是TeA,平均值为1890.16μg·kg^(-1),TEN次之,平均值为20.26μg·kg^(-1)。

The finely ground sunflower seed sample(2.5g)was taken,and 500.0μL of a mixed internal standard solution containing 100.0μg·L^(-1) of alternariol monomethyl ether-d_(3)(AME-d_(3)),1000.0μg·L^(-1) of tentoxin-d_(3)(TEN-d_(3))and alternariol-d_(2)(AOH-d_(2)),and 5000.0μg·L^(-1) of tenuazonic acid-d_(13)(TeA-d_(13))was added.After mixing well and settling for overnight,the mixture was extracted in 25.0 mL of a mixture of acetonitrile,methanol,and 0.05 mol·L^(-1) sodium dihydrogen phosphate solution(pH 3.0)at a volume ratio of 45∶10∶45,and then centrifuged.The supernatant was taken,and made its volume up to 30.0mL with water.An aliquot(6.0mL)was taken,and 15.0mL of 0.05mol·L^(-1) sodium dihydrogen phosphate solution(pH 3.0)was added.The mixture was passed through Waters Oasis HLB solid phase extraction column(pre-activated with 5.0mL of methanol and 5.0mL of water),and washed with 20%(volume fraction)methanol solution.After drying the solid phase extraction column,it was eluted with 10mL of a mixture of methanol containing 1%(volume fraction)ammonia and acetonitrile at a volume ratio of 1∶1.The eluent was blown to near dryness at 40℃by nitrogen,and then the residue was redissolved in 200.0μL of methanol and made its volume up to 2.0 mL with water.The 4 Alternaria mycotoxins including alternariol(AOH),alternariol monomethyl ether(AME),tenuazonic acid(TeA),and tentoxin(TEN)in the obtained solution were determined by ultra-high performance liquid chromatography tandem mass spectrometry,and internal standard method was used for quantitative analysis.As shown by the results,Waters Oasis HLB solid phase extraction column had the best purification effect,and adding ammonia to the eluant was beneficial for improving peak shape and making the baseline smoother.Linear relationships between values of mass concentration and peak area ratio of targets to internal standards were found in definite ranges,with lower limits of determination(10S/N)in the range of 0.15-1.50μg·kg^(-1).Test for recovery was made by standard addition method,giving results in the range of 75.0%-112%.7parallel tests were performed on the actual sample,with RSDs of the determined values less than 13%.This method was applied to the analysis of actual samples,and it was shown that the highest detection rate and detection amount were for TeA,with an average value of 1890.16μg·kg^(-1),followed by TEN with an average value of 20.26μg·kg^(-1).