Magnetic naphthalene-based polyimide polymer for extraction of Sudan dyes in chili sauce

A facile and rapid method was reported for the preparation of magnetic nanocomposite of naphthalene-based polyimide polymer modified Fe 3 O 4 (Fe 3 O 4 @NPI), which was characterized and explored as sorbents for extraction of Sudan dyes (Sudan I, II, III and IV) in chili sauce prior to their HPLC determination. Some potential parameters influencing the MSPE efficiency were optimized using response surface methodology (RSM). Under the optimal experimental conditions an approach for the analysis of Sudan dyes was developed by coupling with high performance liquid chromatography-diode array detector (HPLC-DAD). Good linearity ( r  > 0.9932) with linear range of 0.05–50 ng L −1 was obtained. The enrichment factors, LODs and LOQs for the proposed method were found to be in the ranges of 80.9–88.9, 0.02–0.05 ng g −1 and 0.07–0.17 ng g −1 , respectively. The method was utilized to analyze target Sudan dyes in real chili sauce samples, and sufficient recoveries ranged from 92.6 to 98.6% were obtained with RSDs <5.8%. These results indicate that the prepared Fe 3 O 4 @NPI is an effective sorbent for the extraction of Sudan dyes prior determination.