Acetylcholine Biosensor Based on Dendrimer Layers for Pesticides Detection

We tested a new design of an enzyme biosensor based on acetylcholinesterase (AChE) and choline oxidase (ChO) immobilized on the supported monomolecular layer composed of poly(amidoamine) (PAMAM) dendrimers of the fourth generation (G4) mixed with 1‐hexadecanethiol (HDT). The resulting enzymatic activity, measured amperometrically, was substantially depressed in the presence of the organophosphate pesticide dimethyl‐2,2‐dichlorovinylphosphate (DDVP, Dichlorvos), carbamate pesticides carbofuran and carbamate drug eserine. The detection limits (1.3×10^?3 ppb for DDVP, 0.01 ppb for carbofuran and 0.03 for eserine) were considerably lower than so far reported for AChE based amperometric and potentiometric sensors. The relative simple protocol of biosensor preparation, high sensitivity and stability is very promising for determination of environmental pollutants in field conditions.     

Rapid and simultaneous analysis of dichlorvos, malathion, carbaryl, and 2,4-dichlorophenoxy acetic acid in citrus fruit by flow-injection ion spray ionization tandem mass spectrometry

A simple method for the rapid and simultaneous analysis of dichlorvos (DDVP), malathion, carbaryl, and 2,4-dichlorophenoxy acetic acid (2,4-D) in citrus fruit, which uses flow-injection ion spray ionization tandem mass spectrometry, has been developed for the first time. The method involves the combined use of stable isotopically labeled internal standards (DDVP-d₆, malathion-d₁₀, carbaryl-d₇, and 2,4-D-d₅) and a multiple reaction monitoring technique. The average recoveries for the pesticides at the same concentrations as their tolerance levels (DDVP: 0.1-0.2 μg g⁻¹; malathion: 0.5-4.0 μg g⁻¹; carbaryl: 1.0 μg g⁻¹; 2,4-D: 1.0-2.0 μg g⁻¹) ranged from 90 to 119% with the relative standard deviation (R.S.D.) ranging from 1.0 to 13.1% (n = 5). Analysis time, including sample preparation and determination, was only 15 min. The present method is effective for screening DDVP, malathion, carbaryl, and 2,4-D in citrus fruit.     

SO42-对TiO2及Ce-TiO2光催化性能的影响

采用溶胶-凝胶法制备了纳米SO42-/Ce-TiO2, SO42-/TiO2及Ce-TiO2光催化剂,并用IR, BET, XPS, XRD等手段对所制得的样品进行表征,将其用于对有机磷农药(DDVP)稀释液的光催化降解,结果表明所制SO42-/Ce-TiO2, SO42-/TiO2具有超强酸特征,其光催化活性较Ce-TiO2有明显提高.     

Calorimetric Determination of Phosphorylated Serum Cholinesterase and Its Reactivation by an Antidote

Abstract

Serum cholinesterase, inhibited in vitro up to 92% by 0, 0 dimethyl-2, 2-dichlorovinyl phosphate (4.52 × 10^?9 mole/ml of 40% serum), was reactivated up to 35% with 2-pyridine aldoxime methiodide (3.5 × 10^?6 mole/ml of 40% serum). Evaluation was based on the reaction rate between cholinesterase and acetylcholine chloride (2.2 × 10^?6 mole) measured with a microcalorimeter. It was thus possible to approximate the “normal” or pre-exposure level of serum cholinesterase, while simultaneously determining the extent of poisoning.     

Acetylcholinesterase Sensor with Patterned Structure for Detecting Organophosphorus Pesticides Based on Titanium Dioxide Sol‐gel Carrier

In this paper, novel and stable acetylcholinesterase (AChE) sensor with patterned structure for detecting organophosphorus pesticides (OPs) based on titanium dioxide sol‐gel carrier was proposed and prepared. Biosensor was assembled by dropping titanium oxide, chitosan (CS) and enzyme to the surface of the glass carbon step by step. The concentration range of the sensor detection for dichlorvos (DDVP) is 1.13 nM to 22.6 μM, and the limit of detection (LOD) is 0.23 nM. It can also detect dichlorvos in cabbage juice samples accurately. The preparation of biosensor adopted a patterned novel structure for the first time, which opens a new way for the structure optimization of organophosphorus pesticide sensor.     

家蝇中乙酰胆碱酯酶的提取纯化及应用研究

研究了用Procainamide亲和层析色谱纯化家蝇头部乙酰胆碱酯酶(AChE),AChE的纯化倍数为63.27倍,产率为93.86%。通过测定AChE活力被抑制的程度可以快速测定敌敌畏和克百威残留量。研究结果表明,在0.09~200μg/L范围内,AChE抑制率与敌敌畏和克百威质量浓度的回归方程分别为Y=9.1321 Lnρ 33.904(r=0.9893),Y=10.738 Lnρ 26.125(r=0.9962);敌敌畏与克百威的检出限分别为1.13±0.42μg/L和2.28±0.76μg/L,对果蔬等实际样品的加标回收率为74%~118%。     

尸体脏器中敌百虫及其主要代谢物DDVP和水合氯醛的毛细柱GC/MS测定

本文应用Finnigan Mat 1020 GC/MS仪,以SE-54熔融硅毛细柱作分离柱,建立了尸体脏器中敌百虫及其主要代谢物DDVP和水合氯醛的分析方法。样品用CH_2Cl_2提取。敌百虫和DDVP的检测限均是15 ng,方法已成功用于刑事案件鉴定。     

敌敌畏的LB气敏膜压电晶体传感器的测定

引用Ｌａｎｇｍｕｉｒ－Ｂｌｏｄｇｅｔ（ＬＢ）膜技术，以ＴｒｉｔｏｎＸ＿１００类脂ＬＢ膜作为测定敌敌畏的敏感材料，使传感器的性能明显提高，检测限是０１μｇ／Ｌ，响应时间、回收时间符合要求，线性范围为０１～１５μｇ／Ｌ，传感器的寿命较长，是一种性能较优的敌敌畏检测器。     

纳米SnO2@TiO2的制备及其光催化性能

以SnCl4和Ti(OBu)4为原料,采用活性层包覆法制备了SnO2@TiO2包覆型复合光催化剂,并用XPS、IR、XRD、TEM和BET等手段进行了表征,以二甲基二氯乙烯基磷酸酯（简称DDVP）稀释液为模拟废水,考察了SnO2@TiO2的光催化活性及降解液初始浓度对反应动力学的影响.结果表明：包覆粒子由锐钛矿型TiO2和金红石型SnO2组成;与纯SnO2、TiO2相比,SnO2@TiO2包覆粒子的光催化活性明显提高,DDVP稀释液被光催化降解属于零级反应,但反应表观速率常数与降解液初始浓度成正比.     

纳米SnO_2@TiO_2的制备及其光催化性能

SnCl4和 Ti(OBu)4为原料,采用活性层包覆法制备了 SnO2@TiO2包覆型复合光催化剂,并用 XPS、 IR、 XRD、 TEM和 BET等手段进行了表征,以二甲基二氯乙烯基磷酸酯（简称 DDVP）稀释液为模拟废水,考察了 SnO2@TiO2的光催化活性及降解液初始浓度对反应动力学的影响 .结果表明：包覆粒子由锐钛矿型 TiO2和金红石型 SnO2组成;与纯 SnO2、 TiO2相比, SnO2@TiO2包覆粒子的光催化活性明显提高, DDVP稀释液被光催化降解属于零级反应,但反应表观速率常数与降解液初始浓度成正比 .