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

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

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。

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.