Determination of organophosphate and carbamate pesticides based on enzyme inhibition using a pH-sensitive fluorescence probe

A flow injection system for the determination of organophosphate and carbamate pesticides is described. A sensitive fluorescence probe was synthesized and used as the pH indicator to detect the inhibition of the enzyme acetylcholinesterase (ACNE). The percentage inhibition of enzyme activity is correlated to the pesticide concentration. Several parameters influencing the performance of the system are discussed. The detection limits of 3.5, 50, 12 and 25 mug/l for carbofuran, carbaryl, paraoxon and dichlorvos, in pure water, respectively were achieved with an incubation time of 10 min. A complete cycle of analysis, including incubation time, took 14 min. The detection system has been applied to the determination of carbofuran in spiked vegetable juices (Chinese cabbage and cole), achieving recovery values between 93.2 and 107% for Chinese cabbage juice and 108 and 118% for cole juice at the different concentration levels assayed. (C) 2004 Elsevier B.V. All rights reserved.

用模型拟合法研究1,2-聚丁二烯分子运动

本文采用Cole-Cole,Fuoss-Kirkwood经验相关时间分布模型和构象跳跃,高聚物局部主链运动阻尼取向扩散分子模型,对1,2-聚丁二烯在溶液中的~(13)C-NMR自旋-晶格弛豫时间nT_1和核Overhauser效应(NOE)值进行了数值拟合。用拟合所得分子运动参数讨论了1,2-聚丁二烯微观分子运动对链结构和温度的依赖性。