Synthesis and Characteristics of Polymer-Mediated Curcumin Molecular Imprinting for Quantitative Determination of Curcumin in Food Samples.

In this study, a molecularly imprinted polymer (MIP)-based extraction process for determining curcumin in food samples was carried out. MIP and NIP were thermally synthesized in acetonitrile solvent (porogen) using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linking agent, azobisisobutyronitrile as an initiator, and curcumin as a template molecule. Parameters affecting the synthesis process, such as temperature, the ratio of the components in the reaction, and the extraction solvent, were investigated. The characteristics of the synthesized material were examined using infrared spectroscopy and scanning electron microscopy. The maximum adsorption capacity of the material was found to be 1.34 mg/g MIP with an adsorption efficiency of 89.96% for MIP and 12.35% for NIP. The MIP material exhibited high selectivity for curcumin compared to other compounds such as quercetin (18.00%), rutin (14.74%), and ketoconazole (0.00%). The analysis method for curcumin using the MIP material was performed with validated parameters including linear range (1 - 25 mg/L, r2 = 0.9997), accuracy (recovery rate of 90.90 %), precision (RSDR = 0.338 %, RSDr = 1.591 %), detection limit (0.051 mg/L), and quantification limit (0.156 mg/L). The validation results indicated that the HPLC-DAD method was entirely suitable for analyzing the curcumin content in food samples.

Analytical techniques for determination of heavy metal migration from different types of locally made plastic food packaging materials using ICP-MS.

Plastic food packaging is an essential element for customer convenience and the preservation of food quality. Nonetheless, heavy metals in the packaging materials, either intentionally or nonintentionally added, can be transferred to the food. Therefore, determining heavy metal contents in these packaging materials is essential. In this study, heavy metals, including Co, Ge, As, Cd, Sb, Pb, Al, and Zn from different intrinsic plastic food packaging materials were analyzed using the inductively coupled plasma-mass spectrometry (ICP-MS) method. Moreover, the migration of these elements into the environment was also investigated. This method is validated following the new technique's requirements, which include linearity range, accuracy, precision, the limit of detection (LOD), and the limit of quantitation (LOQ). The method has been suitably validated with the regression equation from the standards prepared in HNO3 1% v/v. The linear range was found to be ~1-20 ng mL-1 for Co, Ge, As, Cd, Sb, and Pb and 5-80 ng mL-1 for Al and Zn elements. The LODs are ~0.10, 0.25, 0.12, 0.13, 0.11, 0.12, 0.61, and 0.85 ng mL-1, and the LOQs are 0.33, 0.83, 0.40, 0.43, 0.36, 0.40, 2.01, and 2.81 ng mL-1 obtained for Co, Ge, As, Cd, Sb, Pb, Al, and Zn, respectively. In addition, the recovery percentages received ranged 85.4%-94.1% for Co, 82.6%-95.1% for Ge, 86.3%-97.9% for As, 87.3%-96.3% for Cd, 88.0%-104.4% for Sb, 96.3%-106.0% for Pb, 88.4%-104.0% for Al, and 95.1%-99.7% for Zn. Finally, the migration of these heavy metals from polypropylene (PP) and polystyrene (PS) into foodstuffs was also simulated according to EU legislation, showing that the most leached element was Zn, followed by Al and Pd, with the migration of ~8.38% and ~0.41%, and ~0.19%, respectively.

Formation of a CdO layer on CdS/ZnO nanorod arrays to enhance their photoelectrochemical performance.

The performance and photocatalytic activity of the well-known CdS/ZnO nanorod array system were improved significantly by the layer-by-layer heterojunction structure fabrication of a transparent conductive oxide (TCO) CdO layer on the CdS/ZnO nanorods. Accordingly, a CdO layer with a thickness of approximately 5-10 nm can be formed that surrounds the CdS/ZnO nanorod arrays after annealing at 500 °C under air. At an external potential of 0.0 V vs. Ag/AgCl, the CdO/CdS/ZnO nanorod array electrodes exhibit an increased incident photon to conversion efficiency, which is significantly higher than that of the CdS/ZnO nanorod array electrodes. The high charge separation between the electrons and holes at the interfaces of the heterojunction structure results from the specific band energy structure of the photoanode materials, and the unique high conductivity of the CdO layer is attributed to the suppression of electron-hole recombination; this suppression enhances the photocurrent density of the CdO/CdS/ZnO nanorod arrays. The photoresponse of the electrodes in an electrolytic solution without sacrificial agents indicated that the CdO layer also has the ability to suppress the well-known photocorrosive behavior of CdS/ZnO nanorods.

Axis-oriented, continuous anatase titania films with exposed reactive {100} facets.

Homogeneous TiO2 single crystals with high exposure of {100} reactive facets were constructed as a seed monolayer on transparent conductive substrates with the desired orientation of reactive facets. A secondary growth process was subsequently carried out on the monolayer seed film to form an axis-oriented continuous reactive film. Performing secondary growth with different precursors led to optimized conditions for high-performance photoelectrochemical activity of anatase TiO2 films. Experimental techniques such as UV/Vis absorption spectroscopy, X-ray diffraction, high-resolution SEM, and photoelectrochemistry were used to characterize the structural, optical, and photoelectrochemical properties of the as-synthesized films. As a photoanode in a photoelectrochemical cell, the axis-oriented reactive film shows a maximum photocurrent density of 0.3 mA cm(-2), as opposed to 0.075 mA cm(-2) for non-axis-oriented (randomly oriented) TiO2 film.