Analysis of unauthorized Sudan dyes in food by high-performance thin-layer chromatography

Abstract

Food authenticity and food safety are of high importance to organizations as well as to the food industry to ensure an accurate labeling of food products. Respective analytical methods should provide a fast screening and a reliable cost-efficient quantitation. HPTLC was pointed out as key analytical technique in this field. A new HPTLC method applying caffeine-impregnated silica gel plates was developed for eight most frequently found fat-soluble azo dyes unauthorizedly added to spices, spice mixtures, pastes, sauces, and palm oils. A simple post-chromatographic UV irradiation provided an effective sample cleanup, which took 4 min for up to 46 samples in parallel. The method was trimmed to enable 23 simultaneous separations within 20 min for quantitation or 46 separations within 5 min for screening. Linear (4-40 ng/band) or polynomial (10-200 ng/band) calibrations of the eight azo dyes revealed high correlation coefficients and low standard deviations. Limits of detection and quantification were determined to be 2-3 and 6-9 ng/zone, respectively. After an easy sample extraction, recoveries of 70-120% were obtained from chili, paprika, and curcuma powder as well as from chili sauce, curry paste, and palm oil spiked at low (mainly 25-50 mg/kg) and high levels (150-300 mg/kg). For unequivocal identification, the compound in a suspect zone was eluted via a column into the mass spectrometer. This resulted in the hyphenation HPTLC-vis-HPLC-DAD-ESI-MS. Graphical abstract Simplified clean-up by UV irradiation for Sudan dye analysis in food by HPTLC-vis-HPLC-DAD-ESI-MS.

Rapid UV/Vis Spectroscopic Dye Authentication Assay for the Determination and Classification of Reactive Dyes, Monascus Pigments, and Natural Dyes in Coloring Foodstuff

“…Périat et al recently published a SWATH-MS (sequential window acquisition of all theoretical mass spectra) method for the detection of permitted and prohibited artificial food dyes in spices. Further screening methods include the use of HPLC and HPTLC techniques. , The advantage of chromatographic or mass spectrometric methods compared to that of RaSDAY is that the detection of adulteration as well as the identification of the adulterant is possible within one method. However, these methods that target only predefined adulterants do not include the authenticity approach proposed by Moore et al as discussed in the Introduction.…”

ELISA Test on Cordia myxa L. Leaf Extract for alpha-Glucosidase Inhibitor

“…It important to know that sensitivity of this equipment can detect the compound which is cannot detect by TLC. 20 The data above will assist to investigated for furthermore for the compounds from the sample by elucidation method to determinate the potential compound that can inhibit the α-glucosidase. 21 ELISA assay on the sample as showed on Table 2.…”

CI Solvent Yellow 14 (Sudan I) identified as the allergen in a plastic part of glasses

“…It has previously been reported as a contact allergen in different cosmetics . It has also been used in textiles and food, but is now prohibited in food in the EU and is listed in REACH annex XVII, entry 43 (Azocolourants and Azo dyes) . This means that it may not be used in clothes or other products that may come into direct and prolonged contact with the human skin.…”