Sudan I

Sudan I is an organic compound, typically classified as an azo dye.

In Vitro:Sudan I is a monoazo dye with the chemical formula of 1-phenylazo-2-naphthol. Sudan I can cause tumors in the liver or urinary bladder in mammals and is a potential mutagen and carcinogen for humans. Sudan I induces genotoxic effect in HepG2 cells and increases mutagenic and clastogenic effects in the MCL-5 cell lines compared to the AHH-1 cell line. In addition, Sudan I also gives positive results in Salmonella Typhimurium mutagenicity tests with S9 activation, a post-mitochondrial fraction prepared from the livers of rats[1].

References:
[1]. Pan H, et al. Evaluation of impact of exposure of Sudan azo dyes and their metabolites on human intestinal bacteria. Anaerobe. 2012 Aug;18(4):445-53.

Aqueous solution behaviour and solubilisation properties of octadecyl cationic gemini surfactants and their comparison with their amide gemini analogues.[Pubmed:29292439]

Soft Matter. 2018 Jan 31;14(5):754-764.

Gemini surfactants 18-s-18(Et), comprised of two ethylammonium headgroups and two alkyl tails with m = 18 carbon atoms with spacers of s = 4, 6, 8 and 10 linking the headgroups (alkanediyl-alpha,omega-bis(diethyloctadecylammonium bromides)), were obtained. Their aqueous solution behaviour, including adsorption at the interface and aggregation in solution, was followed by tensiometric, conductometric and spectroscopic methods. The critical micelle concentration (CMC) of the surfactants decreased with increasing spacer length. The size of 18-s-18(Et) aggregates formed at concentrations of 10 and 40 CMC measured by DLS varied with the elongation of the spacer. Visualisation of aggregated surfactant structures at 40 CMC by cryo-TEM evidenced the formation of different morphologies depending on spacer length. Gemini with s = 4 formed elongated, cylindrical micelles, while geminis of s = 6, 8 and 10 self-assembled into vesicles. The ability of the studied geminis to solubilise hydrophobic dye Sudan I in water was determined as a function of surfactant concentration, demonstrating their high efficiency. Results for 18-s-18(Et) geminis were compared with those previously obtained for their analogues containing an amide group placed between headgroups and tails. The significant impact of amide groups on the surface activity and aggregation properties of gemini surfactants was evidenced and is related to hydrogen-bond formation by amide-containing compounds.

Preparation of carbon quantum dots from cigarette filters and its application for fluorescence detection of Sudan I.[Pubmed:29754601]

Anal Chim Acta. 2018 Sep 6;1023:115-120.

Carbon quantum dots (CQDs) with quantum yield of 14% were successfully synthesized via a simple, low-cost, and green hydrothermal treatment using cigarette filters as carbon source for the first time. The obtained CQDs showed a strong emission at the wavelength of 465nm, with an optimum excitation of 365nm.Sudan I with maximum absorption wavelength at 477nm could selectively quench the fluorescence of CQDs. Based on this principle, a fluorescence probe was developed for Sudan I determination. Furthermore, the quenching mechanism of the CQDs was elucidated. A linear relationship was found in the range of 2.40-104.0mumol/L Sudan I with the detection limit (3sigma/k) of 0.95mumol/L. Satisfactory results were achieved when the method was submitted to the determination of Sudan I in food samples.

Diatomite Photonic Crystals for Facile On-Chip Chromatography and Sensing of Harmful Ingredients from Food.[Pubmed:29614728]

Materials (Basel). 2018 Mar 31;11(4). pii: ma11040539.

Diatomaceous earth-otherwise called diatomite-is essentially composed of hydrated biosilica with periodic nanopores. Diatomite is derived from fossilized remains of diatom frustules and possesses photonic-crystal features. In this paper, diatomite simultaneously functions as the matrix of the chromatography plate and the substrate for surface-enhanced Raman scattering (SERS), by which the photonic crystal-features could enhance the optical field intensity. The on-chip separation performance of the device was confirmed by separating and detecting industrial dye (Sudan I) in an artificial aqueous mixture containing 4-mercaptobenzoic acid (MBA), where concentrated plasmonic Au colloid was casted onto the analyte spot for SERS measurement. The plasmonic-photonic hybrid mode between the Au nanoparticles (NP) and the diatomite layer could supply nearly 10 times the increment of SERS signal (MBA) intensity compared to the common silica gel chromatography plate. Furthermore, this lab-on-a-chip photonic crystal device was employed for food safety sensing in real samples and successfully monitored histamine in salmon and tuna. This on-chip food sensor can be used as a cheap, robust, and portable sensing platform for monitoring for histamine or other harmful ingredients at trace levels in food products.

Electrochemiluminescence based competitive immunoassay for Sudan I by using gold-functionalized graphitic carbon nitride and Au/Cu alloy nanoflowers.[Pubmed:29717360]

Mikrochim Acta. 2018 May 1;185(5):275.

A flower-like Au/Cu alloy nanocomposite (Au/Cu NFs) was synthesized and used in an electrochemiluminescence (ECL) based method for sensitive determination of the dye Sudan I. The Au-g-C3N4 nanosheets as an ECL emitter were prepared by electrostatic adsorption between gold nanoparticles and g-C3N4. They form a film on a glassy carbon electrode (GCE) and then can be connected with Sudan I antigen via gold-nitrogen bond and amidation reactions. The Au/Cu NFs combined with Sudan I antibody also via the Au-N bond and was introduced into the modified GCE by specific recognition between the antibody and the antigen. The overlap between emission spectra of the Au-g-C3N4 nanosheets and absorption spectra of Au/Cu NFs enabled the appearance of ECL resonance energy transfer process. That is, when the Sudan I analyte not present, the ECL was weakened due to absorption by the gray Au/Cu NFs on applying voltages from -1.7 V to 0 V. Conversely, the Au/Cu NFs on the GCE are reduced due to the competition for the antibody between the analyte and the antigen. A strong green ECL emission was obtained. The ECL response is linear in the 0.5 pg mL(-1) to 100 ng mL(-1) Sudan I concentration range, and the detection limit is 0.17 pg mL(-1). Graphical abstract An Au/Cu alloy flower-like nanocomposite (Au/Cu NFs) is firstly synthesized as an acceptor to constitute an electrochemiluminescence-resonance energy transfer (ECL-RET) system for sensitive measurement of Sudan I, while Au nanoparticles (Au NPs) functionalized graphitic carbon nitride (g-C3N4) acted as a donor.

Magnetic metal-organic frameworks for fast and efficient solid-phase extraction of six Sudan dyes in tomato sauce.[Pubmed:29665473]

J Chromatogr B Analyt Technol Biomed Life Sci. 2018 Jun 1;1086:146-152.

Magnetic solid-phase extraction is an effective and useful technique to preconcentrate trace analytes from food samples. In this study, a magnetic trimeric chromium octahedral metal-organic framework (Fe3O4-NH2@MIL-101) was fabricated and characterized. Fe3O4-NH2@MIL-101 was applied as an adsorbent of magnetic solid-phase extraction combined with high performance liquid chromatography to effectively isolate and simultaneously determine six Sudan dyes (Para Red, Sudan I-IV, and Sudan Red 7B) from tomato sauce. Potential factors affecting the MSPE were investigated in detail, and adsorption efficiency of Fe3O4-NH2@MIL-101 was compared with those of conventional adsorbents, such as neutral alumina, HLB, and C18. The developed method facilitated the extraction with using only 3mg of adsorbent in 2min. In addition, enhancement factors of 50, linear range of 0.01-25mug/mL, and detection limit (S/N=3) of 0.5-2.5mug/kg were obtained. The intra-day and inter-day recoveries for spiked Sudan dyes were in the range of 72.6%-92.9% and 69.6%-91.6%, respectively, with relative standard deviations of

Aerobic Biodegradation Characteristic of Different Water-Soluble Azo Dyes.[Pubmed:29278390]

Int J Environ Res Public Health. 2017 Dec 26;15(1). pii: ijerph15010035.

This study investigated the biodegradation performance and characteristics of Sudan I and Acid Orange 7 (AO7) to improve the biological dye removal efficiency in wastewater and optimize the treatment process. The dyes with different water-solubility and similar molecular structure were biologically treated under aerobic condition in parallel continuous-flow mixed stirred reactors. The biophase analysis using microscopic examination suggested that the removal process of the two azo dyes is different. Removal of Sudan I was through biosorption, since it easily assembled and adsorbed on the surface of zoogloea due to its insolubility, while AO7 was biodegraded incompletely and bioconverted, the AO7 molecule was decomposed to benzene series and inorganic ions, since it could reach the interior area of zoogloea due to the low oxidation-reduction potential conditions and corresponding anaerobic microorganisms. The transformation of NH(3)-N, SO(4)(2-) together with the presence of tryptophan-like components confirm that AO7 can be decomposed to non-toxic products in an aerobic bioreactor. This study provides a theoretical basis for the use of biosorption or biodegradation mechanisms for the treatment of different azo dyes in wastewater.

Non-targeted detection of paprika adulteration using mid-infrared spectroscopy and one-class classification - Is it data preprocessing that makes the performance?[Pubmed:29622186]

Food Chem. 2018 Aug 15;257:112-119.

A method for the non-targeted detection of paprika adulteration was developed using Fourier transform mid-infrared (FT-MIR) spectroscopy and one-class soft independent modelling of class analogy (OCSIMCA). One-class models based on commercially available paprika powders were developed and optimised to provide >80% sensitivity by external validation. The performances of the established models for adulteration detection were tested by predicting spiked paprika samples with various types of fraudulent material and levels of adulterations including 1% (w/w) Sudan I, 1% (w/w) Sudan IV, 3% (w/w) lead chromate, 3% (w/w) lead oxide, 5% (w/w) silicon dioxide, 10% (w/w) polyvinyl chloride, and 10% (w/w) gum arabic. Further, the influence of data preprocessing on the model performance was investigated. Relationship between classification results and data preprocessing was identified and specificity >80% was achieved for all adulterants by applying different preprocessing methods including standard normal variate (SNV), first and second derivatives, smoothing, and combinations thereof.