Search

[Display omitted] • Estimation of micron-sized microplastics in tea infusion by Raman imaging. • Detection of submicron- and nano-sized microplastics in tea infusion by Py-GC/MS. • Woven tea bags release far fewer microplastics than nonwoven tea bags. • Pre-washing reduced 76–94% micron- and 80–87% submicron-sized microplastic. Microplastics released from plastic-based filter bags during tea brewing have attracted widespread attention. Laser confocal micro-Raman and direct classical least squares were used to identify and estimate micron-sized microplastics. Characteristic peaks from pyrolysis-gas chromatography/mass spectrometry of polyethylene terephthalate, polypropylene, and nylon 6 were selected to construct curves for quantification submicron-sized microplastics. The results showed that microplastics released from tea bags in the tea infusions ranged from 80 to 1288 pieces (micron-sized) and 0 to 63.755 μg (submicron-sized) per filter bag. Nylon 6 woven tea bags released far fewer microplastics than nonwoven filter bags. In particular, a simple strategy of three pre-washes with room temperature water significantly reduced microplastic residues with removal rates of 76 %–94 % (micron-sized) and 80 %–87 % (submicron-sized), respectively. The developed assay can be used for the quantitative evaluation of microplastics in tea infusions, and the pre-washing reduced the risk of human exposure to microplastics during tea consumption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Visualization of microplastics in crayfish using LCM-Raman imaging. • Microplastics were detected in the gills, intestines, and ovaries of crayfish. • Crayfish exposed to 9 mg/L of microplastics accumulated 13,000 particles in 28 days. • RPV values can quantitatively evaluate the contamination level of microplastics. Crayfish is one of the most important freshwater aquaculture species in China. The potential risks of crayfish consumption caused by environmental microplastic pollution have attracted much attention. In this study, a total of 72 crayfish samples were exposed to the microplastic concentrations of 1 mg/L, 3 mg/L, and 9 mg/L for 7, 14, and 28 days, and microplastic contamination levels in crayfish were then explored by laser confocal micro-Raman (LCM-Raman) imaging and scanning electron microscope (SEM). LCM-Raman imaging showed better performance in microplastics identification. Besides, the average percentage of the contaminated area in visualized LCM-Raman images was used to quantitatively assess contamination levels. Following 28 days of exposure to 9 mg/L microplastics, microplastic accumulation reached about 13,000 particles per crayfish. The results confirmed that LCM-Raman imaging combined with image processing technology could be used to construct a high-performance analytical strategy for the assessment of microplastic contamination in crayfish. [ABSTRACT FROM AUTHOR]

Highlights: [•] A cephalosporins enrichment technique based on C18-Fe3O4@mSiO2 was developed. [•] The mesopores on the surface of the microspheres exclude proteins. [•] The strong magnetic behaviors of the microspheres ensure a fast separation. [ABSTRACT FROM AUTHOR]

• A novel electrochemical probe PB@ZIF-8/PDA/IgG was proposed. • The advantages of PB, ZIF-8 and PDA collaborated to enhance detection sensitivity. • The developed immunosensor had a detection limit of 0.0186 pg mL−1. • Proposed immunosensor was used for detection of deoxynivalenol in grain products. The presence of deoxynivalenol (DON) in grains poses a threat to human health, which is critical for sensitive detection of DON. In this electrochemical immunosensor, zeolitic imidazolate framework-8 (ZIF-8) loaded with Prussian blue (PB) nanoparticles was coated by polydopamine (PDA) as a redox probe. The high porosity of ZIF-8, the unique electrochemical activity of PB and the outstanding electrical conductivity of PDA improved the sensitivity of the immunosensor. Under the optimized conditions, the peak current in differential pulse voltammetry displayed a good linear relationship over DON concentrations in a range of 0.1–5000 pg mL−1 with a detection limit of 0.0186 pg mL−1. In addition, the immunosensor also had good selectivity and stability. Good recoveries of 85.67 to 118.00 % have been achieved for the detection of DON in spiked grain products. This new strategy exhibits great potential for simple and rapid detection of DON in grain and feed products. [ABSTRACT FROM AUTHOR]

[Display omitted] • In situ stability analysis of blueberry anthocyanins (BAs) by Raman spectroscopy. • Multivariate analysis explained BA degradation in aqueous solutions in bottles. • High temperature, high pH, and ultraviolet irradiation caused BA degradation. • Multi-factor perturbations exacerbated BA degradation. Blueberry anthocyanin (BA) is a functional ingredient to enhance the biological activity of food, and the stability of BA is of great interest. BA stability in aqueous solutions stored in polypropylene and glass bottles was analyzed in-situ using confocal Raman spectroscopy, and the acceptable depth of focus was optimized. The Raman characteristics of BA degradation were explained by multivariate analysis. The degradation rate of BA was significantly accelerated by heating above 65 °C for 2 h or ultraviolet irradiation (10 W) for 96 h. The first order kinetic reaction rate was accelerated with the increase of pH value and temperature and the prolongation of ultraviolet irradiation time. The synergistic effect of multiple factors promoted BA degradation. This study provides an in-situ, nondestructive method for the analysis of anthocyanin stability, which has great utility in the food industry to optimize processing, storage, and transportation measures to reduce the degradation of BA. [ABSTRACT FROM AUTHOR]