全自动在线固相萃取-二维高效液相色谱与质谱联用测定辣椒油中苏丹红

Two-Dimensional High Performance Liquid Chromatography Combined with On-line Solid Phase Extraction and Mass Spectrometry for Determination of Sudan Dyes in Chili Oil

建立了全自动在线固相萃取-二维高效液相色谱与质谱联用快速测定辣椒油中的苏丹红Ⅰ,Ⅱ,Ⅲ,Ⅳ的方法。样品经乙腈和二氯甲烷萃取后,在一维色谱柱(Acclaim PAⅡ,150 mm×3.0 mm×3μm)上分离出苏丹红,通过阀的分段切换,依次富集在SPE柱(Acclaim 120 C18,10 mm×4.6 mm×5μm)上,在线完成净化和萃取富集;再通过阀切换将它们转移至二维色谱流路,在Acclaim 120 C18色谱柱(100 mm×2.1 mm×2.2μm)上分离检测。一维色谱以水-乙腈-甲醇/四氢呋喃(1∶1,V/V)为流动相,进样体积20μL,0.6 mL/min流速梯度洗脱和紫外-可见检测器(λ=254 nm)监测分离状况;二维色谱以水-乙腈-甲酸/乙腈(1∶1000,V/V)为流动相,0.3 mL/min流速梯度洗脱,采用单四极质谱仪,选择离子方式检测。整个分析流程27 min即可完成。4种苏丹红的保留时间的相对标准偏差均小于0.1%,色谱峰面积的相对标准偏差均小于2%(n=7);在0.6～60μg/L范围内峰面积与进样质量浓度的线性相关系数均大于0.9958;加标回收率为50%～97%;方法检出限均小于0.2μg/L(S/N=3)。测定结果令人满意。

A two-dimensional HPLC coupled with on-line solid phase extraction（on-line SPE） and mass spectrometric method was developed for the determination of Sudan dyes（Ⅰ,Ⅱ,Ⅲ,and IV） in chili oil.After extracted by acetonitrile-methylene dichloride,the analytes in chili sample were separated on the first-dimension column（Acclaim PA Ⅱ,3 μm,3.0 × 150 mm）,then they were trapped on the SPE column（Acclaim 120 C18,5 μm,4.6 × 10 mm） in turn using valve-switching technique for extraction and purification.Finally,the trapped analytes were transferred to the second-dimension column（Acclaim 120 C18,2.2 μm,2.1 × 100 mm） using valve-switching technique as well.The mobile phase used for the first-dimension was water-acetonitrile-methanol/tetrahydrofuran（1 ∶ 1,V/V） with a flow rate of 0.6 mL/min in gradient elution mode.A 20-μL sample was injected into the first-dimension column and then detected by UV detection at wavelength of 254 nm.The mobile phase used for on-line SPE was 0.1% formic acid in water at 1.0 mL/min flow rate in isocratic elution mode.The separation and quantitative on the second-dimension was carried out by using water-acetonitrile-formic/acetonitrile（0.1 ∶ 100,V/V） as mobile phase at 0.3 mL/min flow rate in gradient elution mode,and mass spectrometry detection with electrospray ionization（ESI） source.The analysis may be completed within 27 min.The relative standard deviations（RSD） for the detection of Sudan dyes（Ⅰ-Ⅳ） were all less than 0.09% for retention time,and less than 1.9% for peak area（n=7）.A good linearity was obtained in the Sudan dyes concentration ranged from 0.6 to and 60 μg/L（R2≥0.9958）.The recoveries standard addition spiked in commercial chili were in the range of 50%-97%;and the limits of detection for this method were all less than 0.2 μg/L（S/N=3）.