QuEChERS提取-高效液相色谱-高分辨质谱法测定水产品中3种蓝藻毒素的含量

取水产品样品2.00g与2g无水硫酸钠混匀后加入提取剂10 mL甲醇,涡旋振荡5min后超声提取5 min,再离心5 min,取其上清液。在上清液中加入500 mg中性氧化铝和15mg石墨化碳黑(GCB)涡旋振荡1min,离心5min,取上清液,于40℃下吹氮至近干,用体积比为1∶1的流动相A-流动相B混合溶液溶解残渣并定容至2.0mL,经0.22μm滤膜过滤,取其滤液按高效液相色谱-高分辨质谱法测定其中3种蓝藻毒素的含量。色谱分离中用Hypersile Gold C8色谱柱(150mm×2.1mm,3μm)为固定相,用不同比例的流动相A和流动相B两溶液的混合液作为流动相进行程序梯度洗脱。质谱测定中采用电喷雾离子源,正、负离子切换模式。由于3种蓝藻毒素均产生基质减弱效应,制作工作曲线需用基质标准溶液以消除基质效应。结果表明:所测3种蓝藻毒素均在10~200μg·L^-1内与其峰面积之间呈线性关系,其检出限(3S/N)均为5μg·kg^-1。通过标准加入法进行回收试验,测得回收率为68.3%~104%,测定值的相对标准偏差(n=6)为7.7%~17%。

Determination of 3 Cyanobacteria Toxins in Aquatic Products by High Performance Liquid Chromatography-High Resolution Mass Spectrometry with QuEChERS Extraction

A portion of sample of aquatic product(2.00 g)was extracted ultrasonically for 5 min with 10 mL of CH3 OH after mixing with 2 g of anhydrous sodium sulfate,and centrifuged for 5 min.The supernatant was taken and purified by swirling for 1 min with 500 mg of neutral alumina and 15 mg of graphitized carbon black,and then centrifuged for 5 min.The supernatant was taken and evaporated to near-dryness by N2-blowing at 40℃.The residue was dissolved in and with its volume made up to 2.0 mL of a mixed solution of mobile phase A-mobile phase B with the volume ratio of 1∶1.The solution was then filtered through 0.22μm filtering membrane and the filtrate was used for determination of 3 cyanobacteria toxins by high performance liquid chromatography-high resolution mass spectrometry.In the liquid chromatography separation,Hypersile Gold C8 column(150 mm×2.1 mm,3μm)was used as stationary phase and mixtures of solution(A)and(B)in various ratios were used as mobile phases in the gradient elution.Electrospray ionization with mode of switching of cation and anion was adopted in mass spectrometry determination.Matrix matching was used in preparation of standard curves of the 3 cyanobacteria toxins to overcome matrix effects.Standard curves of the 3 cyanobacteria toxins were obtained in the same range of 10-200μg·L^-1,with their same detection limits(3 S/N)of 5μg·kg^-1.Values of recovery found by test for recovery by standard addition method were in the range of 68.3%-104%,and values of RSDs(n=6)were found ranged from 7.7%to 17%.