Bioavailability is a critical factor for assessing the environmental risk of organic pollutants in soil. In this study, extractions with 3 different solvents, including 2 aqueous solutions, calcium chloride(CaCl_2) an...Bioavailability is a critical factor for assessing the environmental risk of organic pollutants in soil. In this study, extractions with 3 different solvents, including 2 aqueous solutions, calcium chloride(CaCl_2) and a phosphate buffer solution(PBS), and a mixture of aqueous solution and organic solvent, a PBS-methanol(8:2,volume/volume) mixture(PBS-M), were performed to assess the bioavailability of chlorimuron-ethyl in soil in comparison to a battery of toxicity tests in wheat seedlings. The results indicated that the peroxidase(POD) activity in wheat leaves after 7 d of exposure was one of the sensitive biomarkers of chlorimuron-ethyl in soil.The extractability of chlorimuron-ethyl by all the 3 solvents decreased with exposure time, and the rate of decrease of the PBS-M extraction between 1 and 7 d of exposure was substantially higher than those of the aqueous solution extractions. Chlorimuron-ethyl gradually changed from a water-soluble form into a soil organic matter(SOM)-bound form in the soil. The PBS extraction correlated best with the POD activity in the leaves after 7 d of exposure.展开更多
A sensitive electrochemical immunoassay system for the detection of a protein tumor biomarker through a dual amplified strategy was reported. Firstly, this protocol involves in the electropolymerization of o-aminobenz...A sensitive electrochemical immunoassay system for the detection of a protein tumor biomarker through a dual amplified strategy was reported. Firstly, this protocol involves in the electropolymerization of o-aminobenzoic acid (o-ABA) on a glass carbon electrode (GCE). Subsequently, capture anti-CEA (Abl) is covalently linked to poly(o-ABA) (PAB) film, via N-(3-dimethylamminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), and N-hydroxysulfosuccinimid sodium salt (NHS) activation of the carboxyl groups and surface blocking with ethanolamine. Later, the target, carcinoembryonic antigen (CEA), is sandwiched between an electrode surface confined Ab1 and the alkaline phosphatase-labeled signal anti-CEA antibodies conjugated with gold nanoparticles (Ab2-ALP-AuNP bioconjugates). The dual biocatalytic signal amplification for CEA monitoring is achieved by coupling the numerous enzymes loaded on the AuNPs with redox-recycling of the enzymatic products in the presence of the secondary enzyme and the corresponding substrate. The novel dramatic signal amplification strategy, exhibits a good linearity at the studied concentration range from 0.005 to 50 ng mL-1 towards CEA with a detection limit of 2 pg mL-1 (S/N=3). There is a 5-100-fold improvement in detection limit compared to other similar studies. The developed dual signal amplified strategy shows good selectivity, regeneration, stability and acceptable reproducibility. Therefore, the signal amplification approach holds great potential applications in detection of ultra-trace protein biomarkers.展开更多
基金supported by the National Natural Science Foundation of China(Nos.41401565,41201520 and 20807046)
文摘Bioavailability is a critical factor for assessing the environmental risk of organic pollutants in soil. In this study, extractions with 3 different solvents, including 2 aqueous solutions, calcium chloride(CaCl_2) and a phosphate buffer solution(PBS), and a mixture of aqueous solution and organic solvent, a PBS-methanol(8:2,volume/volume) mixture(PBS-M), were performed to assess the bioavailability of chlorimuron-ethyl in soil in comparison to a battery of toxicity tests in wheat seedlings. The results indicated that the peroxidase(POD) activity in wheat leaves after 7 d of exposure was one of the sensitive biomarkers of chlorimuron-ethyl in soil.The extractability of chlorimuron-ethyl by all the 3 solvents decreased with exposure time, and the rate of decrease of the PBS-M extraction between 1 and 7 d of exposure was substantially higher than those of the aqueous solution extractions. Chlorimuron-ethyl gradually changed from a water-soluble form into a soil organic matter(SOM)-bound form in the soil. The PBS extraction correlated best with the POD activity in the leaves after 7 d of exposure.
基金supported by the National Natural Science Foundation of China (20905062 & 20675064)the Natural Science Foundation Project of Chongqing City (CSTC-2009BB5003 & CSTC-2009BA1003)+1 种基金China Post-doctoral Science Foundation (20090460715)research funds from Southwest University (SWUB2008078 & XDJK2009B013)
文摘A sensitive electrochemical immunoassay system for the detection of a protein tumor biomarker through a dual amplified strategy was reported. Firstly, this protocol involves in the electropolymerization of o-aminobenzoic acid (o-ABA) on a glass carbon electrode (GCE). Subsequently, capture anti-CEA (Abl) is covalently linked to poly(o-ABA) (PAB) film, via N-(3-dimethylamminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), and N-hydroxysulfosuccinimid sodium salt (NHS) activation of the carboxyl groups and surface blocking with ethanolamine. Later, the target, carcinoembryonic antigen (CEA), is sandwiched between an electrode surface confined Ab1 and the alkaline phosphatase-labeled signal anti-CEA antibodies conjugated with gold nanoparticles (Ab2-ALP-AuNP bioconjugates). The dual biocatalytic signal amplification for CEA monitoring is achieved by coupling the numerous enzymes loaded on the AuNPs with redox-recycling of the enzymatic products in the presence of the secondary enzyme and the corresponding substrate. The novel dramatic signal amplification strategy, exhibits a good linearity at the studied concentration range from 0.005 to 50 ng mL-1 towards CEA with a detection limit of 2 pg mL-1 (S/N=3). There is a 5-100-fold improvement in detection limit compared to other similar studies. The developed dual signal amplified strategy shows good selectivity, regeneration, stability and acceptable reproducibility. Therefore, the signal amplification approach holds great potential applications in detection of ultra-trace protein biomarkers.