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Molecularly imprinted polymers with methylammonium lead halide perovskite quantum dots (MIP@MAPbBr3 PQDs) have been prepared and applied to the determination of benzo(a)pyrene (BaP) for the first time. The photoluminescence (PL) of MIP@MAPbBr3 PQDs was enhanced due to the surface passivation of defects by BaP. PL excitation and emission spectra, X-ray diffraction, Fourier transform infrared, and time-resolved PL studies suggest that the interaction between MIP@MAPbBr3 PQDs and BaP is a dynamic process. After MIP@MAPbBr3 PQDs were incubated with BaP, the benzene ring in the molecular structure of BaP can interact with MIP@MAPbBr3 PQDs through π electrons, which reduces non-radiative recombination of MIP@MAPbBr3 PQDs and lengthens excited state lifetime. The PL intensity of the MIP@MAPbBr3 PQDs-BaP system was monitored at 520 nm with 375 nm excitation. Under optimized conditions, the PL intensity of MIP@MAPbBr3 PQDs is linear with the concentration of BaP in the 10 to 100 ng·mL−1 range, with a detection limit of 1.6 ng·mL−1. The imprinting factor was 3.9, indicating excellent specificity of MIP@MAPbBr3 PQDs for BaP. The MIP@MAPbBr3 PQDs were subsequently applied to the PL analysis of BaP in sunflower seed oil, cured meat, and grilled fish samples, achieving recoveries from 79.3 to 107%, and relative standard deviations below 10%. This molecularly imprinted fluorescence assay improves the selectivity of BaP in complex mixtures and could be extended to other analytes. [ABSTRACT FROM AUTHOR]

In this work, loofah sponge (LS) was treated with sodium hydroxide to remove lignin and hemicellulose and retain hydroxyl-rich cellulose on its surface. The treated LS was used for solid-phase extraction (SPE) of trans-resveratrol (TRA) based on their hydrogen bond interactions. A new simple method for the determination of TRA in peanut oils was developed by coupling LS-based SPE with high-performance liquid chromatography-ultraviolet detection (HPLC–UV). The linear range of the developed method was within the range of 25–2500 ng/g with a satisfactory correlation coefficient (R2) of 0.9995 and the limit of detection (LOD) of 6.6 ng/g. In addition, the recoveries of TRA ranged from 93.8 to 98.6% with relative standard deviations (RSDs) of less than 1.8%. Finally, the developed method was successfully applied to the analysis of TRA in several different peanut oils as well as other vegetable oils. The results showed that only peanut oils contained TRA, which can be used for identifying the adulteration of peanut oils. [ABSTRACT FROM AUTHOR]

Phenoxy carboxylic acid herbicides (PCAs) are widely used in agricultural production. However, due to their potential threat to human health, it is necessary to develop efficient analysis method for monitoring PCA concentration in environment and food samples. Based on dispersive micro-solid phase extraction (D-μ-SPE) with amine-functionalized metal–organic framework MIL-101(Fe)-NH2, a selective, sensitive, and cost-efficient method was proposed for the extraction of PCAs from environmental water and rice samples in this study. From the perspective of adsorption kinetics and isotherms, interaction mechanisms between MIL-101(Fe)-NH2 and PCAs were investigated. Key parameters of D-μ-SPE procedure including adsorbent dosage, solution pH, ionic strength, eluting solution, and washing solutions were optimized. Using of small amount of MIL-101(Fe)-NH2 could achieve desirable extraction effect due to its large surface area and multiple interactions with PCAs. Under the optimized D-μ-SPE conditions, calibration curves of 8 PCAs were linear within a concentration range of 0.05–5 ng/mL for water samples (r2 > 0.9898) and 0.5–50 ng/g for rice samples (r2 > 0.9879). Limits of detection of water and rice samples were as low as 0.004–0.008 ng/mL and 0.05–0.1 ng/g, respectively. The recoveries of 8 PCAs ranged from 83.0 to 109.3%. Both inter- and intra-day relative standard deviations were less than 10.3%. Our proposed method was successfully employed in actual environmental water and rice samples. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) are one class of brominated flame retardants (BFRs). Although studies have reported the occurrence of PBDEs in freshwater fish species from several locations, to our best knowledge, there was no comprehensive data on PBDEs in foods of animal origin, such as pork, egg, and milk samples from interior areas of China, where pork and eggs are the major constituents of diet. The levels of PBDEs (BDE-28, 47, 99, 100, 153, 154, and 183) were determined in samples of animal-derived foods widely consumed by the population of Hubei in east-central China and the middle reaches of the Yangtze River. Two hundred six samples of animal-derived foods were randomly acquired in 17 sites of Hubei in 2010. The highest medium concentration of ∑PBDEs was found in chicken eggs (0.191 ng/g wet weight (ww)), followed by duck eggs (0.176 ng/g ww), pork (0.050 ng/g ww), carps (0.047 ng/g ww), and cow milk (0.013 ng/g ww). The estimated dietary intake of ΣPBDEs for a standard adult of 60 kg body weight based on medium and 95th percentile concentrations with consumption of animal-derived foods in Hubei province were 157.5 and 1960.3 pg/kg body weight/day, respectively. Chicken eggs (65.9 %) and pork (23.4 %) were the largest contributors to dietary intake of ∑PBDEs through animal-derived foods. The same PBDE sources were exposed in Hubei province via principal component analysis (PCA), and the particular congener profile in samples of animal-derived foods revealed the possible exposure history of octa-BDEs and penta-BDEs in the local region. The large margins of exposure (MOE) calculated following the European Food Safety Authority (EFSA) approach for three important congeners, BDE-47, BDE-99, and BDE-153, indicated that the estimated dietary exposures were unlikely to be a significant health concern to in Hubei. [ABSTRACT FROM AUTHOR]