curcumin and metanil-yellow

Topics: Carbon; Curcuma; Curcumin; Europium; Fluorescence; Powders

The present study aimed to develop a sensitive and available method for determining metanil yellow (MY) as an adulterating agent in food samples. Solid-phase extraction was chosen for pre-concentrating metanil yellow prior to its determination using a validated UV-spectrophotometric method. The precipitation polymerization method was applied to synthesize a range of molecularly imprinted polymers (MIPs) for selective extraction of MY. Polymers were characterized by SEM and FTIR and investigated for MY extraction through batch rebinding experiments. The extraction process was optimized in the term of pH, time, capacity, and the desorbing solvent. Results of this study showed the critical role of template/functional monomer ratio in the preparation of the MIPs. The developed MIP solid-phase extraction/UV-spectrophotometric method was employed for determining MY in spiked samples and showed 88.10-92.76% recovery for turmeric samples containing 0.1-10 mg/kg MY. The developed method was shown selective for MY in the presence of another azo dye.

Topics: Azo Compounds; Curcuma; Light; Molecular Imprinting; Molecularly Imprinted Polymers; Solid Phase Extraction; Spectrophotometry

In this study, a simple Benzimidazole based bifunctional chemosensor 4-(2-(3,4-dimethoxyphenyl)-1H-benzo[d]imidazol-6-yl) benzene-1,2-diamine, L was synthesized and characterized. The sensor proved to be selective and sensitive towards detecting banned azo dyes Sudan Dye I, II, and Metanil Yellow via fluorescence turn-off response. The proposed mechanism of fluorescence quenching was the inner filter effect. LODs for Sudan I, II, and Metanil Yellow were found to be 0.009 µM, 0.012 µM, and 0.0073 µM, respectively. The developed chemosensor also showed a colorimetric response towards Cu (II) ions via an apparent color change from yellow to pink. LOD for Cu (II) ions was found to be 1.2 µM. The synthesized benzimidazole based bifunctional chemosensor was adequately tested to determine Sudan I in Red chili powder and red Food color samples, Metanil yellow in turmeric powder, and Cu(II) packaged coconut water.

Topics: Azo Compounds; Cocos; Curcuma; Naphthols

Turmeric sourced from six retailers was processed into a powder and adulterated with metanil yellow (MY) at concentrations of 0.0 to 30% (w/w). A handheld near-infrared spectrometer was used to obtain spectral scans of the samples, which were preprocessed using Savitzky-Golay first-derivative (SG1) approximation using 61 smoothing points and second-order polynomial. The preprocessed spectra were analyzed using principal component analysis (PCA) followed by classification by soft independent modeling class analogy (SIMCA) and were used to group the adulterated turmeric powder samples according to the source (i.e., processor) of adulteration. Results showed the first principal component (PC1) of PCA models was sensitive to adulteration level, but when coupled with SIMCA, unadulterated and adulterated samples could be classified according to their source despite having high levels of MY. At 5% level of significance, all of the samples were correctly classed for origin during validation. Some samples were classified under two groups, indicating possible inherent similarities. When the PCA model was built using only unadulterated samples, the PCA-SIMCA model could not classify the adulterated samples but could classify those with very low levels (≤2%, w/w) of MY, allowing for segregation of adulterated samples but not identification of sources. The combination of near-infrared and PCA-SIMCA modeling is a great tool not only to detect adulterated turmeric powder but also, potentially, to deter it in the future because the source of adulterated food can be traced back to the source of adulteration.

Topics: Azo Compounds; Curcuma; Food Contamination; Powders; Principal Component Analysis; Spectroscopy, Near-Infrared

Adulteration of medicinally valuable curcumin (CU) with harmful chemicals as metanil yellow (MY) in recent years have demanded for quick detection techniques of the adulterants. The voltammetric behavior of CU and MY on bare glassy carbon electrode (BGCE) and carbon quantum dots modified glassy carbon electrode (CQDs/GCE) was studied by both cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in phosphate buffer solution of pH 5.4. The MY responded to the CQDs/GCE with two anodic peaks at -0.004 V and 0.136 V and two cathodic peaks at -0.112 and -0.048 V. Under similar conditions CU exhibited two anodic peaks at 0.28 V and 0.55 V and one cathodic peak at 0.25 V. The overlapped voltammogram obtained for CU and MY on BGCE was well separated on the CQDs/GCE. The interference studies revealed that the compounds, demethoxycurcumin and bisdemethoxycurcumin, which are commonly associated with CU, did not interfere with the detection of MY. Real sample was analyzed with fabricated electrode and the recovery values >98% were obtained.

Topics: Azo Compounds; Carbon; Curcumin; Electrochemical Techniques; Electrodes; Quantum Dots