固相萃取-高效液相色谱荧光法同时测定辣椒面中罗丹明B和罗丹明123

目的:建立固相萃取-高效液相色谱荧光法同时测定辣椒面中罗丹明B和罗丹明123的分析方法。方法:样品经甲醇/水溶液(1∶1,V/V)提取,过Strata-X-CW固相萃取小柱净化,用Kromasil C18色谱柱(250 mm×4.6 mm×5μm)以含0.1%甲酸(V/V)的乙腈/水为流动相进行梯度洗脱分离,荧光检测器测定,罗丹明B采用λex556 nm,λem581 nm,罗丹明123采用λex518 nm,λem542 nm检测,外标法定量。结果:罗丹明B在2.0μg/L～100.0μg/L和罗丹明123在1.0μg/L～50.0μg/L范围均具有良好的线性(R2>0.9994),2种待测物的回收率在94.5%～104.6%范围,RSD均小于5.0%,最低定量检出限在1.0μg/kg～2.0μg/kg范围。结论:该方法具有前处理简单,梯度洗脱分离效果和重现性好等优点,能满足实际工作的需要。

Simultaneous analysis of rhodamine B and rhodamine 123 in chilli powder by high performance liquid chromatography with fluorescence detection after solid-phase extraction

Objective:To develop a method for the simultaneous determination of rhodamine B and rhodamine 123 in chilli powder by high performance liquid chromatography with fluorescence detection.Methods:Chilli powder samples were extracted using methanol-water(1:1,V/V),and cleaned up with Strata-X-CW SPE cartridges.Chromatographic separation was performed on a Kromasil C18 analytical column(250 mm×4.6 mm×5 μm) with a gradient elution using formic acid solution(0.1%,V/V)-acetonitrile as mobile phase.The rhodamine B and rhodamine 123 were detected by fluorescence detector at excitation wavelength(λex) 556 nm and 518 nm,and emission wavelength(λem) 581 nm and 542 nm,respectively.Results:Linearities of the method were in the range of 1.0 μg/L～50.0 μg/L and 2.0 μg/L～100.0 μg/L with determination coefficients(R2) higher than 0.9994 for rhodamine 123 and rhodamine B,respectively.Recoveries were in the range of 94.5%～104.6%,and the relative standard deviations(RSDs) were lower than 5%.The limit of quantification(LOQs) for rhodamine B and rhodamine 123 were in the range of 1.0 μg/kg～2.0 μg/kg.Conclusion:The developed method has the advantages of simple pretreatment,efficient separation and high reproducibility,and it can be applied to the determination of the two rhodamines in chilli powder.