A multi-residue method for determination of pesticide residues in vegetables, using ethyl acetate extraction and determination by means of GC–MSD, is presented. The method includes as many as 27 pesticides such as organophosphorous, organohalogen, organonitrogen and pyrethroids pesticides, which are in common use or forbidden on vegetables in China. After extraction with ethyl acetate, the extract is concentrated and evaporated to dryness and redissolved in ethyl acetate before injection on GC–MSD. The recoveries were obtained in the range 70–100% with 5 exceptions in lettuce and 7 exceptions in cucumber, relative standard deviations between 1.92% and25.39% by means of standard addition to the vegetables blank extracts. The degradation of some pesticides in the 27 was studied by the method developed, the mixture of the pesticides commercial formulations was sparged on the vegetables, then the residues of samples obtained in different time were determined by the developed method. The determination indicated that (all pesticides were used as the instruction): 1.a pesticide, used on different plants, the quantity of the pesticide on the part for people’s dietary differs greatly; 2. some pesticides, degradating slowly and with a large dose, are inappropriate used on vegetables which remain on cropland for a short time. This research does not develop models for pesticides degradation, but provides some data on the safe intervals of the pesticides and a potential method for the study of multi-class pesticides safe intervals on a plant simultaneously.
The objective of this study was to investigate the effects of salinity on power generation and microbial community structure in the microbial fuel cell (MFC). Three two-chamber MFCs (MFC-A, MFC-B, MFC-C) were used to conduct experiments. The MFC-A was operated sequentially using solutions of 0, 20, 40, 60, and 70 g/L NaCl in the anode chamber of the cell. The MFC-B was operated with solutions of 0 and 40 g/L NaCl and the MFC-C with solutions of 0 and 70 g/L NaCl. Results showed that the salinity inhibited power generation in all the MFCs. In the MFC-A, the maximum voltage outputs and CEs decreased from 660 to 130 mV and from 67% to 4%, respectively, with the NaCl concentrations from 0 to 70 g/L. However, the NaCl concentrations did not affect the removal efficiency of substrate (glucose) in the MFC, which reached 100% at the end of every cycle. Moreover, voltages could be recovered to the maximum value (630 mV) within 60 h after replacing the salt solutions with water. With the solutions of 40 and 70 g/L NaCl in the MFC-B and MFC-C, respectively, no obvious electricity was generated after two cycle operations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.