Multiclass and multi-residue determination of pesticides and antibiotics in sediment from an aquacultural environment based on modified dispersive solid-phase extraction.

A quick, easy, cheap, effective, rugged, and safe method was developed for the multi-residue analysis of pesticides and antibiotics in aquaculture sediment using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The developed method is based on ultrasonic extraction with acetonitrile and phosphate buffer, salting with sodium chloride, and cleaning with dispersive solid-phase extraction adsorbent using primary secondary amine, C18, and graphitized carbon black, followed by HPLC-MS/MS detection. We optimized different extraction methods and the ratio of the cleanup adsorbents to achieve good recoveries at three spiking levels that ranged from 60.4% to 114% with a relative standard deviation below 15% (n = 6). For all analytes, except for flufenoxuron, the limits of quantification were between 1 and 5 µg/kg (dry weight). The validated method was successfully applied to real samples collected from 20 aquacultural ponds, confirming the feasibility of the proposed method. The concentrations of the target analytes in the sediments (dry weight) were in the ranges of 2.2-35.0 µg/kg for sulfonamides, 0-409.1 µg/kg for quinolones, 0-6.56 µg/kg for macrolides, and 0-4.9 µg/kg for pesticides. Moreover, the co-occurrence of pesticides and antibiotics may potentially pose a high risk to sediment-dwelling organisms in nine out of the 20 investigated locations.

Levels, distribution and risk assessment of hexabromocyclododecane (HBCD) in fish in Xiamen, China.

In this study, hexabromocyclododecane (HBCD) was detected in 114 fish samples collected from 6 administrative regions of Xiamen city, China. HBCD amounts ranged between ND (not detected) and 2.216 ng g-1 ww (mean, 0.127 ± 0.318 ng g-1 ww). Besides, α-HBCD was the main diastereoisomer in these fish specimens, followed by ß-HBCD. Meanwhile, γ-HBCD was not detected in any of the samples. Significant differences were recorded among fish species. The results indicated that the levels and detection rates of HBCD were higher in Trachinotus ovatus compared with other aquatic organisms. Therefore, Trachinotus ovatus could be used as a marine biological indicator of HBCD. Within the regions investigated, Siming was significantly different from Jimei, Haicang, and Xiang'an. The spatial distribution of HBCD concentrations indicated higher mean levels in samples collected from Haicang, Jimei, and Xiang'an, respectively, with the highest detection rates in Jimei and Xiang'an, which might be related to geographical location and intense industrial and urban activities. Estimation of daily HBCD intake was performed according to fish consumption in Xiamen residents. The medium bound HBCD amounts in fish were approximately 0.073 and 0.088 ng kg bw-1d-1 for male and female residents of Xiamen, respectively. Exposure doses of HBCD indicated no health concern for Xiamen residents.

Spatiotemporal characteristics and pollution level of brominated flame retardants in bivalves from Fujian southern coastal areas.

The concentration and spatiotemporal distribution of brominated flame retardants (BFRs), including hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA), were analyzed in bivalves from Fujian southern coastal areas. The concentrations of HBCD and TBBPA ranged from ND (not detected) to 5.540 ng·g-1 (ww) (median of 0.111 ng·g-1) and ND to 0.962 ng·g-1 (ww) (median of ND), respectively. In addition, α-HBCD was found as the predominant diastereoisomer in all the studied samples, followed by ß-HBCD and γ-HBCD. The spatial distribution of BFRs showed a peak distribution, with the content being higher in the marine environment of Xiamen and Quanzhou, in South Fujian, and lower toward the marine environment of Zhangzhou, and Putian. BFRs contamination level was correlated to the bay geographical location and proximity to local industries. Furthermore, the results of the study showed a seasonal variation pattern: summer > autumn > spring > winter. This study provides base information on the contamination status of these BFRs in the marine environment of southern Fujian.

Sensing HIV related protein using epitope imprinted hydrophilic polymer coated quartz crystal microbalance.

We have developed a biomimetic sensor for the detection of human immunodeficiency virus type 1 (HIV-1) related protein (glycoprotein 41, gp41) based on epitope imprinting technique. gp41 is the transmembrane protein of HIV-1 and plays an important role in membrane fusion between viruses and infected cells. It is an important index for determining the extent of HIV-1 disease progression and the efficacy of therapeutic intervention. In this work, dopamine was used as the functional monomer and polymerized on the surface of quartz crystal microbalance (QCM) chip in the presence of template, a synthetic peptide with 35 amino acid residues, analogous to residues 579-613 of the gp41. This process resulted in grafting a hydrophilic molecularly imprinted polymer (MIP) film on the QCM chip. QCM measurement showed that the resulting MIP film not only had a great affinity towards the template peptide, but also could bind the corresponding gp41 protein specifically. The dissociation constant (K(d)) of MIP for the template peptide was calculated to be 3.17 nM through Scatchard analysis, which was similar to those of monoclonal antibodies. Direct detection of the gp41 was achieved quantitatively using the resulting MIP-based biomimetic sensor. The detection limit of gp41 was 2 ng/mL, which was comparable to the reported ELISA method. In addition, the practical analytical performance of the sensor was examined by evaluating the detection of gp41 in human urine samples with satisfactory results.

A quartz crystal microbalance sensor based on mussel-inspired molecularly imprinted polymer.

In this work, we describe a simple, inexpensive and fast method for the generation of molecularly imprinted polymer (MIP) film on quartz crystal microbalance (QCM) crystals using mussel-inspired polymer. Commonly known as a neurotransmitter, dopamine is also a small-molecule mimic of the adhesive proteins of mussels. Polymerization of dopamine in the presence of template molecule (1,3,5-pentanetricarboxylic acid, an analogue of domoic acid, in this case) could produce an adherent molecularly imprinted polydopamine film coating on QCM crystals. Advantages, such as high hydrophilicity, high biocompatibility and controllable thickness, make this molecularly imprinted polydopamine film an attractive recognition element for sensors. Selective rebinding of domoic acid on mussel-inspired molecularly imprinted polymer (m-MIP) coated crystal was observed as a frequency shift quantified by piezoelectric microgravimetry with the QCM system. The decreasing frequency shows a good linear relationship with the concentration of domoic acid. The quantitation limit of domoic acid was 5 ppb with the linear range of 0-100 ppb. The QCM sensor has high selectivity and was able to distinguish domoic acid from its analogous p-phthalic acid and o-phthalic acid owing to the molecular imprinting effect. In addition, the practical analytical performance of the sensor was examined by evaluating the detection of domoic acid in mussel extracts with satisfactory results. It is envisaged that m-MIP could be suitable as recognition element for sensors and the proposed m-MIP QCM sensor could be employed to detect analyte of interest in complex matrices.