Hybrid peptide-molecularly imprinted polymer interface for electrochemical detection of vancomycin in complex matrices.

A hybrid recognition interface combining peptide and molecularly imprinted polymer (MIP) was achieved by introducing a vancomycin binding tripeptide in the preparation of MIP to implement high affinity and specificity recognition of vancomycin in complex matrices. The tripeptide that can specifically bind vancomycin was immobilized onto gold nanoparticles (GNPs) deposited on a glassy carbon electrode (GCE) by Au-S bond, and then a controlled electropolymerization of dopamine was carried out to imprint the vancomycin-peptide complex. After removing vancomycin from the polydopamine (PDA), hybrid peptide-MIP cavities containing multiple binding sites for vancomycin in the MIPDA/peptide/GNPs/GCE were obtained. The electrode had better selectivity and higher sensitivity toward vancomycin than either peptide or MIP modified GNPs/GCE, and the limit of quantification was as low as 10 pM by electrochemical impedance spectroscopy. The real samples, including fetal calf serum, probiotic drink and honey spiked with 0.17-2.0 µM vancomycin were analyzed on the MIPDA/peptide/GNPs/GCE, with the recoveries of 92.16-104.67%. The present study provides a sensitive, reliable method for the detection of vancomycin in complex matrices.

Amplification effect of haze on human exposure to halogenated flame retardants in atmospheric particulate matter and the corresponding mechanism.

The health impact of haze is of great concern; however, few air quality studies have investigated trace pollutant contamination in the air. Size-segregated atmospheric particles (nine size fractions derived from PM10) were collected in dwelling (indoor) and traffic (outdoor) environments in Xinxiang, China, during light pollution conditions (air quality index (AQI), 60-90) and heavy pollution conditions (AQI, 350-550), and they were analysed for halogenated flame retardants (HFRs), including polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs) and Dechlorane Plus (DP) isomers. HFR occurrence levels generally decreased in the order of PBDEs > NBFRs > DPs. The total mean abundance ratios of heavy pollution/light pollution were 4.0, 2.9, 4.4 and 3.6 for PBDEs, NBFRs, DPs and HFRs, respectively. Meteorological conditions played distinctive roles in the HFR distribution in the air. Apparent differences were found for the particle size distribution of HFRs under light and heavy pollution conditions. In general, for adults, the estimated hazard quotient (HQ) and incremental lifetime cancer risk (ILCRBDE-209) values were approximately 1.7 × 10-2 and 9.3 × 10-9 in heavy pollution conditions, respectively, which were significantly higher than those in light pollution conditions (1.8 × 10-3 and 2.1 × 10-9, respectively).

[Particle Size Distribution and Human Health Risk Assessment of Heavy Metals in Atmospheric Particles from Beijing and Xinxiang During Summer].

Under a condition of good air quality (AQI:55-90, PM10:37-97 µg·m-3, PM2.5:17-76 µg·m-3), six groups of 54 samples were collected using an Andersen cascade impactor from both the indoor and outdoor stations in Beijing and Xinxiang from June to August in 2016. The samples were digested by microwave digestion, and nine heavy metal elements (Pb, Cr, Ni, Cu, Zn, As, Cd, Mn, and Co) in the atmospheric particles were determined with an inductively coupled plasma source mass spectrometer (ICP-MS). The results showed that the enrichment index (0-3) of most elements were low in both cities except for Cd[15.0 (Beijing) and 8.47 (Xinxiang)]. Cr, Co, Cu, and Mn in the atmospheric particles from Beijing park, Cd, Pb, and Mn in the atmospheric particles from the Beijing office, Cr, Co, Ni, and As in the atmospheric particles from Xinxiang park, and all nine heavy metal elements in the atmospheric particles from roads in both cities were found to be more concentrated in the coarse fractions; however, Pb, Zn, Cd, Ni, and As in the atmospheric particles from Beijing park, Co, Zn, Ni, Cr, As, and Cu in the atmospheric particles from the Beijing office, Pb, Zn, Cd, Cu, and Mn in the atmospheric particles from Xinxiang park, and all nine metal elements in the atmospheric particles from the Beijing office showed the opposite pattern. The result of a human health risk assessment indicated that the carcinogenic risk of the five carcinogenic elements were all less than 10-4, but a lower potential cancer risk would also occur under long term exposure. For the four non-carcinogenic elements (Pb, Zn, Mn, and Cu), the non-carcinogenic health risk values of Pb, Zn, Mn, and Cu in the atmospheric particulates in Beijing were all far less than 1, which means the corresponding non-carcinogenic risk was negligible; and, except for Mn, there was no obvious non-carcinogenic risk from Pb, Zn, and Cu in the atmospheric particles of Xinxiang.