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Chemical Reviews 01/2013; · 40.20 Impact Factor
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ABSTRACT: Conventional solid phase microextraction (SPME) has a limited capacity to extract very polar analytes, such as adenosine. To solve this problem, aptamer conjugating sol-gel methodology was coupled with an SPME fiber. According to the authors' knowledge, this is the first reported use of aptamer SPME. The fiber of aptamer sol-gel SPME with a mesoporous structure has high porosity, large surface area, and small water contact angle. Rather than employing direct entrapment, covalent immobilization was the dominant method of aptamer loading in sol-gel. Aptamer sol-gel fiber captured a specified analyte from among the analog molecules, thereby, exhibiting an excellent selective property. Compared with commercial SPME fibers, this aptamer fiber was suitable for extracting adenosine, presenting an extraction efficiency higher than 20-fold. The values of repeatability and reproducibility expressed by relative standard deviation were low (9.4%). Interestingly, the sol-gel network enhanced the resistance of aptamer SPME to both nuclease and nonspecific proteins. Furthermore, the aptamer sol-gel fiber was applied in human plasma with LOQ 1.5μg/L, which is an acceptable level. This fiber also demonstrates durability and regeneration over 20-cycles without significant loss of efficiency. Given the various targets (from metal ions to biomacromolecules and cells) of aptamers, this methodology will extend the multi-domain applications of SPME.
Journal of chromatography. A 01/2013; · 4.19 Impact Factor
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ABSTRACT: Long-term field and modeling studies were performed to measure and predict occurrence, accumulation, attenuation and priority of typical antibiotics in sediments of the Dagu River in China. The results indicated that the concentrations of antibiotics ranged from lower than the limit of detection to 12.4mg/kg, depending on the accumulation time of these antibiotics in sediments. Compared with the residential and industrial areas, the agricultural region of the watershed was a major source of antibiotic contamination in sediments. Accumulation and attenuation kinetics models were established and successfully applied in the field study. For instance, by 2100, the accumulation model predicted that the concentrations of roxithromycin and oxytetracycline would rise to 13 and 7.3mg/kg, respectively. The first and second order attenuation kinetics models revealed the fate of these antibiotics along the downstream and upstream sediments, respectively. The half-life distances of antibiotic attenuation ranged from 3.5 to 12.4km. Based on the contamination level and trend, a priority factor and an accumulation growth factor were defined to identify the priority pollutants from the antibiotics. Gentamicin and roxithromycin were recognized as the top priority pollutants among the tested antibiotics. In the future, a wider applicability of the methods and models needs to be explored and suggested.
Journal of hazardous materials 05/2012; 225-226:91-8. · 4.14 Impact Factor
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ABSTRACT: The extraction method of pharmaceutical and personal care products (PPCPs) has become a popular issue due to the emergence
of PPCPs as contaminants. In this work, polycyclic musks, a typical type of PPCPs, were selected to test various techniques
including microwave-assisted extraction (MAE), simultaneous distillation-solvent extraction (SDSE), Soxhlet extraction (SE),
and ultrasound probe (UP). MAE and UP proved to be more effective pretreatment techniques than SE and SDSE, with high recovery,
repeatability, accuracy, efficiency, little solvent consumption, and acceptable matrix effects. Notably, the chemical methods
usually did not work well for the determination of bioavailability and the environmental fate of pollutants was overestimated.
In this work, wheat (Triticum aestivum L.) was used as the ecological receptor to evaluate the bioavailability of chemical pollutants. The concentrations of polycyclic
musks in sediments by way of UP extraction had a significant correlation (R
2>0.9, P<0.01) with the concentrations in roots of wheat and the changes of chlorophyll, malondialdehyde and peroxidase in leaves
of wheat. These changes suggest that the concentrations of polycyclic musks in sediments using UP extraction were comparable
with the level of those in vivo. Through this work, it was discovered that using UP with a different solvent was suitable
for determining total concentrations and the bioavailable fractions in sediments.
KeywordsGas chromatography–mass spectrometry–Microwave-assisted extraction–Ultrasound probe–Polycyclic musk–Bioavailability
Chromatographia 05/2012; 74(5):489-495. · 1.20 Impact Factor
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ABSTRACT: Analysis of antibiotics in the environment has become an urgent issue. A novel method entailing microwave-assisted extraction
(MAE) and high-performance liquid chromatography–electrospray mass spectrometry (LC–MS
n
) has been developed for determination of selected typical antibiotics, including quinolones, sulfonamides, and tetracyclines,
in manure. Compared with ultrasonic extraction, MAE significantly increased recovery of fluoroquinolones (63–106%), sulfonamides
(64–133%), and tetracyclines (64–109%) from manure. Acetonitrile acidified with formic acid buffer solution (pH 4.0) was used
for extraction of swine manure whereas chicken manure was extracted with 0.1M EDTA–McIlvaine buffer solution. Limits of quantification
(LOQ) for all compounds were in the range 5.12–168.4μgkg−1 dry matter, which were satisfactory for analysis of all samples. The suitability of the method was assessed by analysis of
manure from six different sites.
KeywordsColumn liquid chromatography-Microwave-assisted extraction-Mass spectrometry-Tetracyclines-Sulfonamides-Fluoroquinolones-Manure
Chromatographia 04/2012; 71(3):217-223. · 1.20 Impact Factor
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ABSTRACT: The contaminations of peptide toxins in drinking water lead directly to sickness and even death in both humans and animals. A smart RNA as aptamer is covalently immobilized on graphene oxide to form a polydispersed and stable RNA-graphene oxide nanosheet. RNA-graphene oxide nanosheets can resist nuclease and natural organic matter, and specifically adsorb trace peptide toxin (microcystin-LR) in drinking water. The adsorption data fit the pseudo-second-order kinetics and the Langmuir isotherm model. The adsorption capacity of RNA-graphene oxide nanosheets decreases at extreme pH, temperature, ionic strength and natural organic matter, but it is suitable to adsorb trance pollutants in contaminated drinking water. Compared with other chemical and biological sorbents, RNA-graphene oxide nanosheets present specific and competitive adsorption, and are easily synthesized and regenerated. Aptamer (RNA) covalently immobilized on graphene oxide nanosheets is a potentially useful tool in recognizing, enriching and separating small molecules and biomacromolecules in the purification of contaminated water and the preparation of samples.
Journal of hazardous materials 02/2012; 213-214:387-92. · 4.14 Impact Factor
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ABSTRACT: Targeted delivery drugs by nanoparticles and aptamers is a hot issue; however, the application to ameliorate toxicity of toxicants is unknown, and the information about nanoparticle-aptamer toxicology and pharmacology is limited. In this work, nanoparticle-aptamer was synthesized and then its toxicological and pharmacological information was studied. Mercury was selected as a model toxicant and the antidote was entrapped by nanoparticle-aptamer. The nanoparticle-aptamer with a suitable size of 120 nm avoided aptamer biodegradation and achieved an effective release of antidote. Rats were orally administered mercury-contaminated rice and then nanoparticle-aptamer was intravenously injected. The nanoparticle-aptamer markedly reduced the quantity of mercury in both the brain and kidney, and enhanced the excretion of urinary mercury. Water Maze and Open Field tests showed that nanoparticle-aptamer ameliorated the neurotoxicity and improved the learning and memory of rats. The pharmacology of nanoparticle-aptamer involved slow antidote release, antidote-toxicant antagonism, enhancement of crucial enzymes activity and decreased lipid peroxidation. Toxicology of nanoparticle-aptamer was also studied by hematologic tests (creatinine, urea, red and white blood cell), and exhibited little toxicity. Nanoparticle-aptamer can diminish the toxicity of mercury in vivo with few adverse effects, and is a potential tool in reducing the hazards of toxicants to human health.
Toxicology Letters 01/2012; 208(1):69-74. · 3.23 Impact Factor
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ABSTRACT: Aptamers are a new class of single-stranded DNA/RNA molecules selected from synthetic nucleic acid libraries for molecular recognition. Our group reports a novel aptamer column for the removal of trace (ng/L) pharmaceuticals in drinking water. In this study, cocaine and diclofenac were chosen as model molecules to test the aptamer column which presented high removal capacity, selectivity, and stability. The removal of pharmaceuticals was as high as 88-95%. The data of adsorption were fitted with Langmuir isotherm and a pseudo-second-order kinetic model. A thermodynamic experiment proved the adsorption processes were exothermic in spontaneity. The kinetics of aptamer was composed of three steps: activation, binding, and hybridization. The first step was the rate-controlling step. The adsorption system was divided into three parts: kinetic, mixed, and thermodynamic zones from 0% to 100% binding fraction of aptamer. Furthermore, the aptamer column was reusable and achieved strong removal efficiency from 4 to 30 °C at normal cation ion concentration (5-100 mg/L) for multipollutants without cross effects and secondary pollution. This work indicates that aptamer, as a new sorbent, can be used in the removal of persistent organic pollutants, biological toxins, and pathogenic bacteria from surface, drinking, and ground water.
Environmental Science & Technology 06/2011; 45(11):4890-5. · 4.80 Impact Factor
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ABSTRACT: The residue of antibiotics is becoming an intractable environmental problem in many organic vegetable bases. However, their residual levels and distribution are still obscure. This work systematically analyzed the occurrence and migration of typical veterinary antibiotics in organic vegetable bases, northern China. The results showed that there was no obvious geographical difference in antibiotic distribution between soil and manure. A simple migration model can be easy and quick to predict the accumulation of antibiotics in soil. Antibiotics were mainly taken up through water transport and passive absorption in vegetables. The distribution of antibiotics in a plant was in the sequence leaf>stem>root, and performed biological accumulation. The residues of antibiotics in all samples in winter were significantly higher than those in summer. Overall, this work can lay the foundation for understanding ecological risk of antibiotics and their potential adverse effects on human health by food chain.
Environmental pollution (Barking, Essex: 1987) 09/2010; 158(9):2992-8. · 3.43 Impact Factor
