Fast Cleanup Method for the Analysis of Sudan IIV and Para Red in Various Foods and Paprika Color (Oleoresin) by High-Performance Liquid Chromatography/Diode Array Detection: Focus on Removal of Fat and Oil as Fatty Acid Methyl Esters Prepared by Transesterification of Acylglycerols

Abstract

A fast and effective cleanup method was developed for the analysis of Sudan I, II, III, IV, and Para Red (Sudan dyes) in various foods and paprika color (oleoresin) by high-performance liquid chromatography (LC) with a diode array detector (DAD). Removal of fat or oil in fatty sample was a critical point for reducing the volume of the final sample solution in order to obtain a sufficient level of the analytes. Separation of fat or oil from the dyes with a silica gel solid-phase extraction (SPE) column seemed unfeasible, because elution profiles of oil, fat, and the dyes were similar. Finally, fat and oil were separated from the dyes by elution from the SPE column with n-hexane, not as intact compounds but as fatty acid methyl esters prepared by direct transesterification of acylglycerols in fat and oil, leaving the dyes on the column. The dyes were eluted with n-hexanediethyl ether (9 + 1). Gradient elution with water and tetrahydrofuran was used for separation on a C18 column by LC. Measurement of spectral of μ0.5 g/g of Sudan dyes in foods and 1 μg/g in paprika color (oleoresin) with the DAD was achieved.

Sudan azo dyes and Para Red degradation by prevalent bacteria of the human gastrointestinal tract

“…Para Red is an azo dye used in printing that is chemically similar to Sudan I ( Fig. 1) [17]. Sudan I is a liver and urinary bladder carcinogen in mammals and considered a possible human mutagen [3,18,19].…”

Detection of 1-Amino -2-Naphthol-Based Azo Dyes (Illegal Sudan Dyes) in Some Egyptian Food Products

“…HPLC Model (Dionex Instruments, USA) with version 6.8 chromeleon software was using to record the absorption spectra of the Sudan dyes as the method described by ( Uematsu et al 2007) .The sudans I, II, III, and IV in chili-and curry-containing foodstuffs are extracted from the samples with dichloromethane. Sample extracts are filtered and analyzed by reverse phase HPLC using a 3.6 pH Acetonitiril or methanol (Puoci et al2005).…”

Monitoring the traceability, safety and authenticity of imported palm oils in Europe

“…For example, it is reported that the relatively old and imprecise method of qualitative thin layer chromatography (TLC) is still used by the UK Food Standards Agency to detect Sudan dyes in food products (Oco and Egroodt, 2006;Genualdi et al, 2016). A similar but more advanced method involving diode array detection (DAD), conversion of the oil to FA methyl esters and further purification by silica gel chromatography has also been used successfully (Uematsu et al, 2007). However, both methods have limitations, namely the inability to simultaneously detect Sudan I-IV and the inability to quantify the presence of Sudan dyes.…”