RÉSUMÉ
2,4,6-Trinitrotoluene (TNT) and its by-products dinitrotoluene (DNT) pose a significant threat to human health and other living organisms.However, the conventional analytical methods involved in bulky and expensive instruments are complicated and time-consuming, impeding quick and on-line determination.In this work, a facile yet effective strategy of utilizing UV-vis spectroscopy coupled with partial least squares (PLS) was proposed, through which TNT and two isomers of DNT (2,4-DNT and 2,6-DNT) in nature water could be rapidly and simultaneously determined without any pre-separation.Variable combination population analysis (VCPA) was utilized to select important feather variables and significantly improved the predictive performance of the PLS model.The calibration set contained 25 samples constructed by orthogonal array design (OAD).The predictive ability of the models was validated by an independent prediction set including 15 samples, achieving up to 0.99 of the determination coefficients (R2) for each of the analytes.The optimized models were successfully applied to determine the 3 ingredients in 8 environmental samples involving in tap, lake and two kinds of river water with the recovery values of great than 97%.Finally, the proposed method was further validated by high performance liquid chromatography method.UV-vis spectroscopy coupled with chemometrics may be used as simple and effective strategy with high potential in environmental monitoring.
RÉSUMÉ
Objective To screen the sensing elements for TNT detection in Escherichia coli genome.Methods A genome promoter library with cutting E.coli K-12 MG1655 genome was constructed.Bacterial luciferase luxCDABE was used as a reporter gene during promoter screening.We discovered TNT sensing elements through several rounds of screen-ing.Through analysis of sensitivity, specificity and timeliness, the promoter activity of the elements was evaluated,and the functional sequence of the elements was further confirmed.Results and Conclusion We successfully constructed an E.co-li K-12 MG1655 genome library , from which a TNT sensing element was discovered,which had a good performance in the analysis of sensitivity, specificity and timeliness.In this study, we reported that the topAp4 is a TNT sensing element for the first time.We also verified its excellent promoter activity.
RÉSUMÉ
Objective To establish a capillary gas chromatography method for the determination of trinitrotoluene (TNT) in workplace air.Methods Using dichloromethane as the eluent,the air was drawn through a glass fiber filter to collect TNT,TNT was extracted from the filter with dichloromethane by an ultrasonic shaker,and the sample was analyzed by OV-17 elastic quartz electron capture detector capillary gas chromatography.Results Under the optimal condition,the lowest detection limit was 0.006 ?g/ml,the lowest detection concentration was 0.001 3 mg/m~3 (based on 45 L air sample).When the concentration of standard solution was 0.040-2.0 ?g/ml,the linear equation was good,r=0.999 8,RSDs were between 0.66%-3.62%,the recovery rates were 90.4%-95.5%.When sample was collected by fiberglass filter paper,the efficiency of desorption was more than 90%,and was stable for at least 7 days at 2℃-8℃.Conclusion This method is applicable to the determination of trinitrotoluene in workplace air.