Fast Determination of Sudan I-IV in Chili Products Using Automated On-Line Solid Phase Extraction Coupled with Liquid Chromatography-Mass Spectrometry

摘要

A rapid, accurate and precise method for the determination of sudan I-IV in chili products using on-line solid phase extraction and LC-MS has been developed. Chili products were extracted with acetone and the analytes were cleaned up and enriched on an SPE column (C_(18), 15-40 μm) through on-line SPE. Chromatographic separation was performed on a C_(18) analytical column (2.1 × 150 mm, 3 μm) with gradient elution programming of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. All four sudan dyes were separated in less than 8 min. Using in-house validation data, linearity coefficients of determination (R~2) of more than 0.9997 were obtained. The limits of detection (LOD) and limits of quantitation (LOQ) for sudan I, II and IV were 0.03 and 0.05 mg kg~(-1), respectively, and 0.04 and 0.1 mg kg~(-1) for sudan III. The intra- and inter-day recoveries of the four sudan dyes in chili powder were between 90.1-101.6% and 90.2-102.0%, respectively, with relative standard deviation (RSD) between 0.014-0.164% and 0.011-0.202%, respectively. Therefore, this proposed method could be an alternative assay for the determination of sudan I-IV in chili products due to its rapidness, sensitivity, less sample and solvent consumption.