Appendix 2-5: Rejected ecotox bibliography for Chlorpyrifos



Download 6.25 Mb.
Page135/151
Date conversion04.02.2017
Size6.25 Mb.
1   ...   131   132   133   134   135   136   137   138   ...   151
read-across models for acute toxicity to the standard test organisms Daphnia magna, Pimephales promelas and Selenastrum capricornutum. On the one hand, the prioritization revealed that about three-quarter of the 44 substances with MEC/PNEC ratios above ten were pesticides. On the other hand, based on the monitoring data used in this study, no risk with regard to the water phase could be found for eight of the 41 priority substances, indicating a first success of the implementation of the WFD in the investigated river basins.
Keywords: Chemicals
Keywords: Risk assessment
Keywords: acute toxicity
Keywords: test organisms
Keywords: M2 556:General (556)
Keywords: Europe, Danube R.
Keywords: P 2000:FRESHWATER POLLUTION
Keywords: Statistical analysis
Keywords: River basins
Keywords: Toxicity
Keywords: Risk Abstracts; Environment Abstracts; Meteorological & Geoastrophysical Abstracts; Pollution Abstracts
Keywords: Daphnia magna
Keywords: ENA 02:Toxicology & Environmental Safety
Keywords: Environmental Studies
Keywords: ANE, Netherlands, Scheldt Estuary
Keywords: Pimephales promelas
Keywords: European Union
Keywords: Pesticides
Keywords: Pesticides in river water
Keywords: Environmental quality
Keywords: R2 23050:Environment
Keywords: budgets
Keywords: Europe, Elbe R.
Keywords: Selenastrum capricornutum
Date revised - 2011-10-01
Language of summary - English
Location - ANE, Netherlands, Scheldt Estuary; European Union; Europe, Danube R.; Europe, Elbe R.
Pages - 2064-2077
ProQuest ID - 886064311
SubjectsTermNotLitGenreText - Statistical analysis; Pesticides in river water; Environmental quality; River basins; Risk assessment; Chemicals; acute toxicity; test organisms; Pesticides; Toxicity; budgets; Pimephales promelas; Daphnia magna; Selenastrum capricornutum; ANE, Netherlands, Scheldt Estuary; European Union; Europe, Danube R.; Europe, Elbe R.
Last updated - 2012-08-02
Corporate institution author - Dulio, Valeria; Slobodnik, Jaroslav; De Deckere, Eric; Kuhne, Ralph; Ebert, Ralf-Uwe; Ginebreda, Antoni; De Cooman, Ward; Schuurmann, Gerrit; Brack, Werner
DOI - OB-cc4c5ff5-5d4c-4655-a988csaobj201; 14882440; 0048-9697 English

1441. Vryzas, Z; Alexoudis, C; Vassiliou, G; Galanis, K; Papadopoulou-Mourkidou, E, and Vryzas, Z. Determination and Aquatic Risk Assessment of Pesticide Residues in Riparian Drainage Canals in Northeastern Greece. 2011 Feb; 74, (2): 174-181.


Rec #: 47439
Keywords: SURVEY
Notes: Chemical of Concern: CPY
Abstract: Abstract: An approach combining monitoring and ecotoxicological data has been undertaken to assess pesticide loading in the drainage canals of two transboundary rivers of northeastern Greece near the Greek/Bulgarian/Turkish borders as well as the subsequent risk to non-target aquatic organisms. Aquatic risk assessment was based on the Risk Quotient (RQ=MEC/PNEC) regarding three trophic levels, algae, aquatic invertebrates and fish. Alachlor, atrazine, carbaryl, carbofuran, cypermethrin, DEA, DIA, diazinon, dimethoate, endosulfan, metolachlor, monilate, prometryn and trifluralin were the compounds detected at the highest concentrations on a regular basis. Extreme concentrations were observed just after high rainfall events during the month of pesticide application. Aquatic risk assessment revealed non-acceptable risk for 10 compounds when median concentrations were used as IoeEC values. However, should extreme concentrations be taken into account, 15 compounds were considered as likely to pose a threat to aquatic organisms. Conformity to EC environmental quality standards is also discussed.
Keywords: Risk assessment
Keywords: Aquatic organisms
Keywords: Health & Safety Science Abstracts; Environment Abstracts; Toxicology Abstracts; Pollution Abstracts
Keywords: Pesticide residues
Keywords: Rainfall
Keywords: Carbaryl
Keywords: Pesticide applications
Keywords: H 5000:Pesticides
Keywords: X 24330:Agrochemicals
Keywords: Algae
Keywords: Metolachlor
Keywords: Rivers
Keywords: Data processing
Keywords: Carbofuran
Keywords: Cypermethrin
Keywords: P 2000:FRESHWATER POLLUTION
Keywords: Environmental Studies--Toxicology And Environmental Safety
Keywords: Drainage
Keywords: Alachlor
Keywords: Herbicides
Keywords: Trophic levels
Keywords: ENA 02:Toxicology & Environmental Safety
Keywords: Endosulfan
Keywords: MED, Greece
Keywords: Canals
Keywords: Atrazine
Keywords: Pesticides
Keywords: Trifluralin
Keywords: Environmental quality
Keywords: Dimethoate
Keywords: Diazinon
Date revised - 2011-10-01
Language of summary - English
Location - MED, Greece
Pages - 174-181
ProQuest ID - 852232742
SubjectsTermNotLitGenreText - Metolachlor; Rivers; Risk assessment; Aquatic organisms; Data processing; Cypermethrin; Carbofuran; Pesticide residues; Drainage; Rainfall; Alachlor; Carbaryl; Trophic levels; Pesticide applications; Endosulfan; Canals; Pesticides; Atrazine; Environmental quality; Trifluralin; Dimethoate; Diazinon; Algae; Herbicides; MED, Greece
Last updated - 2011-12-12
Corporate institution author - Vryzas, Z; Alexoudis, C; Vassiliou, G; Galanis, K; Papadopoulou-Mourkidou, E
DOI - OB-4b265a13-f2e9-4ca7-b1d5csamfg201; 14198972; 0147-6513 English

1442. Vryzas, Z.; Vassiliou, G.; Alexoudis, C., and Papadopoulou-Mourkidou, E. Spatial and Temporal Distribution of Pesticide Residues in Surface Waters in Northeastern Greece. 2009; 43, 1-10.


Rec #: 1540
Keywords: SURVEY
Call Number: NO SURVEY (ACR,ATZ,CPY,DZ,MLT,MP,MTL,PDM,PMT,SZ,TFN)
Notes: Chemical of Concern: ACR,ATZ,CPY,DDT,DZ,EFS,HCB,MLT,MP,MTL,PDM,PMT,SZ,TFN

1443. Wacksman, M. Impact of Atrazine on Chlorpyrifos Toxicity to Four Aquatic Vertebrates. 2005: 38 p.


Rec #: 1850
Keywords: PUBL AS,REFS CHECKED
Call Number: NO PUBL AS (ATZ,CPY), NO REFS CHECKED (ATZ,CPY)
Notes: Chemical of Concern: ATZ,CPY

1444. Walker, P. W. and Allsopp, P. G. Factors Influencing Populations of Eumargarodes laingi and Promargarodes spp. (Hemiptera: Margarodidae) in Australian Sugarcane. 1993; 22, (2): 362-367.


Rec #: 2460
Keywords: NO CONC
Call Number: NO CONC (CPY)
Notes: Chemical of Concern: CPY,DLD

1445. Walorczyk, S. and Drozdzynski, D. Improvement and extension to new analytes of a multi-residue method for the determination of pesticides in cereals and dry animal feed using gas chromatography-tandem quadrupole mass spectrometry revisited. 2012; 1251, 219-231.


Rec #: 71479
Keywords: CHEM METHODS
Notes: Chemical of Concern: CPY
Abstract: Abstract: This article describes a substantially improved multi-residue method for the determination of a large number of pesticides in cereal samples (wheat, rye, barley, oats, maze, buckwheat etc.) and various animal feeds. The sample preparation method and the GC-MS/MS acquisition method were modified to accommodate new complex cereal and feed matrices and to extend the existing analytical scope to 167 pesticides. The co-extractives were reduced by the joint use of primary secondary amine (PSA) and octadecyl (C18), 75 mg and 50 mg/1 mL of acetonitrile extract, in the presence of MgSO(4), and thus the optimal recovery and analytical selectivity were obtained simultaneously. The new cleanup procedure was faster and easier to handle than our previously applied cleanup procedure. The overall recoveries of the pesticides from buckwheat and rye at the three spiking levels of 0.01, 0.05 and 0.25 mg kg(-1) were 96 +/- 9% with relative standard deviations of 10 +/- 4% on average. At the lowest spiking level of 0.01 mg kg(-1), 137 of 167 pesticide residues (82%) fulfilled the validation criteria with recoveries in the range of 70-120% and RSDs less or equal 20% whereas in the previous approach it was 93 out of 140 analytes (66%). The developed method was implemented in a routine analysis of approximately 900 real samples, providing an increased scope of the analysis, improved analytical performance parameters and improved ruggedness versus the previous approach. A total of 17% analyzed samples contained pesticide residues. There were 24 different compounds encountered in the samples, of which pirimiphos-methyl, tebuconazole. deltamethrin, and chlorpyrifos-methyl were the most frequent ones. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: Pesticide residue analysis, Gas chromatography, Tandem quadrupole mass
ISI Document Delivery No.: 987PE

1446. Walsh, G. E.; Deans, C. H., and McLaughlin, L. L. Comparison of the EC50s of Algal Toxicity Tests Calculated by Four Methods. 1987; 6, (10): 767-770.


Rec #: 1720
Keywords: NO DURATION
Call Number: NO DURATION (CPY,MP,PMR,PRT,TBC,TBF,TBTF,TBTO,TDC)
Notes: Chemical of Concern: CHD,CPY,HCCP,HMN,HPT,MP,PMR,PRT,TBC,TBF,TBTA,TBTCl,TBTF,TBTO,TDC,TPTH

1447. Walz, I. and Schwack, W. Cutinase inhibition by means of insecticidal organophosphates and carbamates - Part 1: Basics in development of a new enzyme assay. 2007; 225, (3-4): 593-601.


Rec #: 71509
Keywords: IN VITRO
Notes: Chemical of Concern: CPY
Abstract: Abstract: Due to the extensive use of pesticides in agriculture there is an increasing demand for fast performable methods for residue analysis at official food control. This report is concerned with the development of a spectrophotometric enzyme assay in 96-well plate format, with the aim to enable simultaneous screening of multiple samples for organophosphorus and carbamate insecticides by means of their inhibitory effect on cutinase from Fusarium solani pisi. Reaction time of the assay is 30 min. The influence of various solvents on cutinase activity was studied in order to optimize the loss of enzyme activity under organic solvent conditions with respect to pesticide solubility. Methanol concentrations of up to 2.5% in the inhibition batch exhibit negligible influence on cutinase activity. Aqueous mixtures of 10% methanol and 40% diethylene glycol are advantageously bridging restricted pesticide solubility with maintenance of enzyme activity. The detection limit of paraoxon, a potent cutinase inhibitor with an inhibitory rate constant of 1.6 x 10(4) L/(mol min), was determined to 0.04 mg/L. For chlorpyrifos, the most often detected pesticide on fruit and vegetables, the detection limit was 2.6 mg/L with an inhibition constant of 2.0 x 10(3) L/(mol min). Working principle and efficiency of the assay are discussed in detail in terms of enzyme kinetics.
Keywords: enzyme assay, cutinase from Fusarium solani pisi, inhibition, pesticide,
ISI Document Delivery No.: 182JX

1448. ---. Cutinase inhibition by means of insecticidal organophosphates and carbamates Part 2: screening of representative insecticides on cutinase activity. 2008; 226, (5): 1135-1143.


Rec #: 71519
Keywords: IN VITRO
Notes: Chemical of Concern: CPY
Abstract: Abstract: Representative organophosphorus and carbamate insecticides were subjected to a recently developed, efficient spectrophotometric cutinase assay. The inactivation ability of ten organophosphate oxons [chlorpyrifos oxon, chlorpyrifos-methyl oxon, paraoxon, paraoxon-methyl, malaoxon, dichlorvos, monocrotophos, chlorfenvinphos, demeton-S-methyl, acephate], five organophosphate thions [chlorpyrifos, chlorpyrifos-methyl, parathion, parathion-methyl, malathion] and six carbamates [methomyl, carbaryl, propoxur, carbofuran, ethiofencarb, pirimicarb] was examined and characterized in terms of inhibitory rate constants. Regarding their strengths as cutinase inhibitors, organophosphate oxons were found to exceed by far the corresponding thions, whereas ethyl esters proved to be superior to their methyl analogues. Chlorpyrifos oxon with an inhibition constant k (i) of 9.4 x 10(5) L/(mol min) was identified as strongest cutinase inhibitor, resulting in a detection limit of 2 mu g/L (standard solution/sample extract). As novel result it is established that also carbamates are cutinase inhibitors, though of minor strength as compared to organophosphate oxons. Most efficient carbamates are methomyl and carbaryl with inhibition constants of 7.5 x 10(2) and 2.6 x 10(2) L/(mol min), respectively, i.e., well in the range of organophosphorous insecticides.
Keywords: enzyme assay, pesticide, organophosphate, carbamate, cutinase from
ISI Document Delivery No.: 259MD

1449. ---. Reflectometric Cutinase Assay for Rapid Screening of Contaminants and Residues of Insecticidal Organophosphates and Carbamates. 2008; 91, (5): 1130-1137.


Rec #: 71529
Keywords: CHEM METHODS
Notes: Chemical of Concern: CPY
Abstract: Abstract: Because of the extensive use of insecticides in agriculture, there is an increasing demand for rapid analytical methods for residues in food and feed control. To meet this need, a completely new application of the reflectometric lipase test (Reflectoquant (R), Merck) was developed. By using the cutinase-induced reaction of the substrate 5-bromo-4-chloro-3-indoxyl caprylate on the test strips, residues of organophosphates and carbamates can be determined on the basis of enzyme inhibition in a fast and inexpensive way. With this technique, we investigated the inhibition effects of representative insecticides, i.e., chlorpyrifos oxon, paraoxon, and carbaryl. The bimolecular inhibitory rate constants (k(i)) were found to agree well with those obtained by a previously described spectrophotometric cutinase assay in the microtiter-plate format. Recoveries determined with the strip test from spiked samples compared well with those obtained by both the cutinase microtiter-plate assay and liquid chromatography/mass spectrometry.
Keywords: LIPOLYTIC ENZYME, INHIBITION, EXTRACTION, SUBSTRATE, LIPASE, MILK, FOOD
ISI Document Delivery No.: 362XB

1450. Wang, C. M.; Li, X. B.; Liu, Y. H.; Guo, Y. R.; Xie, R.; Gui, W. J., and Zhu, G. N. Development of a Mab-Based Heterologous Immunoassay for the Broad-Selective Determination of Organophosphorus Pesticides. 2010; 58, (9): 5658-5663.


Rec #: 71569
Keywords: CHEM METHODS
Notes: Chemical of Concern: CPY
Abstract: Abstract: A broad-selective monoclonal antibody (Mat)) for organophosphorus (OP) pesticides was raised using heterologous indirect enzyme-linked immunosorbent assay (ELISA) to screen hybridomas. On the basis of this Mab, five coating antigens were used to develop homologous and heterologous indirect competitive ELISAs. With the most suitable competitor, a sensitive and broad-selective ELISA was developed. The IC(50) values were estimated to be 20.32 ng/mL for parathion, 21.44 ng/mL for methyl-parathion, 42.15 ng/mL for fenitrothion, and 58.85 ng/mL for isocarbophos. Spike recoveries were between 70.52 and 103.27% for the detection of single pesticide residues of the four OP pesticides in purple-clayed paddy soil. Moreover, the chosen ELISA was then applied to the detection of mixtures of parathion and methyl-parathion in soil samples. The average recovery and coefficient of variation were 80.91 and 4.82%, respectively. Results proved that this broad-selective ELISA would be useful for the multiresidue determination of OP pesticides.
Keywords: Heterologous, monoclonal antibody (Mab), organophosphorus (OP)
ISI Document Delivery No.: 590OW

1451. Wang, Dongli; Weston, Donald P, and Lydy, Michael J. Method Development for the Analysis of Organophosphate and Pyrethroid Insecticides at Low Parts Per Trillion Levels in Water. 2009 Jun 15; 78, (4-5): 1345-1351.


Rec #: 48489
Keywords: FATE
Notes: Chemical of Concern: CPY
Abstract: Abstract: In the current study, organophosphate and pyrethroid insecticides including diazinon, chlorpyrifos, bifenthrin, fenpropathrin, permethrin, lambda-cyhalothrin, cyfluthrin, cypermethrin, esfenvalerate and deltamethrin were analyzed in laboratory and field-collected water samples. Water samples were extracted and analyzed by gas chromatography/electron capture detector (GC/ECD) and gas chromatography/nitrogen-phosphorous detector (GC/NPD). Comparison of results from liquid-liquid extraction and subsequent normal phase solid-phase extraction cleanup (LLE-NPSPE), and reversed phase solid-phase extraction (RPSPE) showed that LLE-NPSPE was the better choice to extract trace amounts of pesticides from water. Pesticide recoveries from four spiked water samples using LLE-NPSPE ranged from 63.2 to 148.8% at four spiking concentrations. Method detection limits were 0.72-1.69 ng/L using four different water sources. The stability of the target pesticides in lake water was investigated at 4 degrees C for 1h, 1d, 4d, and 7d under three conditions: (1) water samples only; (2) with 20 mL hexane used as a keeper solvent; and (3) with acidification to pH 2 with HCl. Results showed that water storage without treatment resulted in slow degradation of some pesticides with storage time, storage using water acidification led to significant degradation and loss of diazinon and chlorpyrifos, while water storage with hexane as a keeper solvent showed good stability for all of the target pesticides over the 7d storage period.
Keywords: Pesticides -- analysis
Keywords: Water Pollutants, Chemical -- analysis
Keywords: Organophosphates
Keywords: Methods
Keywords: Organophosphates -- isolation & purification
Keywords: Solvents
Keywords: Pyrethrins -- isolation & purification
Keywords: Solid Phase Extraction
Keywords: Chromatography, Gas -- methods
Keywords: Pesticides -- isolation & purification
Keywords: 0
Keywords: Pyrethrins -- analysis
Keywords: Fresh Water -- analysis
Keywords: Pyrethrins
Keywords: Pesticides
Keywords: Water Pollutants, Chemical
Keywords: Organophosphates -- analysis
Keywords: Water Pollutants, Chemical -- isolation & purification
Date completed - 2009-07-30
Date created - 2009-04-13
Date revised - 2012-12-20
Language of summary - English
Pages - 1345-1351
ProQuest ID - 67125582
Last updated - 2013-01-19
British nursing index edition - Talanta, June 15, 2009, 78(4-5):1345-1351
Corporate institution author - Wang, Dongli; Weston, Donald P; Lydy, Michael J
DOI - MEDL-19362199; 19362199; 1873-3573 eng

1452. Wang, Fei; Yao, Jun; Chen, Huilun; Chen, Ke; Treb+íe, Polonca, and Zaray, Gyula. Comparative toxicity of chlorpyrifos and its oxon derivatives to soil microbial activity by combined methods. 2010 Jan; 78, (3): 319-326.


Rec #: 670
Keywords: BACTERIA
Notes: Chemical of Concern: CPY
Abstract: The inhibitory effects of the pesticide Chlorpyrifos (CPF) and its oxon derivative (CPO) on soil microbial activity were evaluated through the measurement of metabolic parameters and the microbial urease enzyme. The thermodynamic parameters related to microbial activity were measured and recorded as powerÇôtime curves. Microbial growth rate constant k, total heat evolution QT, metabolic enthalpy +öHmet, mass specific heat rate JQ/S, microbial biomass C and inhibitory ratio I were calculated. They showed the linear relationship with doses of CPF and CPO. Thereinto, the linear correlations, k versus biomass C and +öHmet versus biomass C, elucidated that k and +öHmet were growth yield dependent. In this work, 20% inhibitory ratio IC20 was obtained with 9.8 ++g gęĆ1 for CPF and 0.37 ++g gęĆ1 CPO, meaning that the acute toxicity of CPO was 26 times that of CPF, since the CPO had more potent toxicity to living organism due to its active functional group. Comparing the change tendency of +öHmet and other parameter, the values almost kept constant when exposure to CPF (<5.0 ++g gęĆ1). It illustrates that individual reacted to stress resulted from environment change by shifting resources from other biological activities (such as reproduction or growth) toward survival to some extent. Urease activity responses in relation to the CPF and CPO exposure were observed and consistent with above thermodynamic parameters. Chlorpyrifos/ Chlorpyrifos-oxon/ Microcalorimetry/ Microbial activity/ Urease activity/ Toxic effect

1453. Wang, G. L.; Liang, B.; Li, F., and Li, S. P. Recent Advances in the Biodegradation of Chlorothalonil. 2011; 63, (5): 450-457.


Rec #: 71599
Keywords: FATE
Notes: Chemical of Concern: CPY
Abstract: Abstract: Chlorothalonil (TPN; 2,4,5,6-tetrachloroisophthalonitrile) has been widely used as a broad-spectrum chlorinated aromatic fungicide and its application resulted in global pollution commonly detected in the diverse ecosystems. Recently, microbial degradation of TPN has been studied extensively as an effective and environmental-friendly method to reduce TPN residue levels in the environment. This review summarizes the current knowledge of recent developments in the biodegradation of TPN. Diverse pure culture strains capable of degrading TPN were widely distributed among Proteobacteria and several metabolic pathways of TPN biotransformation were discovered. The two key genes (glutathione S-transferase and chlorothalonil hydrolytic dehalogenase coding gene) responsible for the conversion of TPN and recent findings for future practical bioremediation of TPN-contaminated ecosystem are also discussed.
Keywords: GLUTATHIONE-S-TRANSFERASE, FUNGICIDE CHLOROTHALONIL,
ISI Document Delivery No.: 823YL

1454. Wang, H. L.; Xu, S. X.; Hu, J., and Wang, X. D. Effect of Potassium Dihydrogen Phosphate and Bovine Manure Compost on the Degradation of Chlorothalonil in Soil. 2009; 18, (2): 195-204.


Rec #: 71609
Keywords: FATE
Notes: Chemical of Concern: CPY
Abstract: Abstract: The effects of potassium dihydrogen phosphate (KH2PO4) and bovine manure compost (BMC) on the degradation and metabolism of chlorothalonil were examined in a sandy loam soil under laboratory conditions. In non-sterilized, non-amended soil, chlorothalonil degradation half-life was 8.8 days. However, it was up to 19.0 days in sterilized non-amended soil, suggesting that the degradation rate was about 2-fold slower than that in non-sterilized non-amended soil. Biological mechanisms accounted for 54.7% of chlorothalonil degradation in non-sterilized soil, indicating that the indigenous microorganisms in soil play an important role in the degradation process. In non-sterilized soil, the more acutely toxic metabolite, 4-OH-chlorothalonil (HTI), of chlorothalonil started forming after the second day of incubation. The concentration of HTI reached its maximum level (2.9 g g- 1) at 10 days after treatment, and no further degradation of HTI was observed in the following span of 20 days (10-30 days of incubation). However, the degradation rate of chlorothalonil was decreased substantially by the addition of KH2PO4 with a half-life of 17.5 days. No formation of HTI was observed before 10 days of incubation and no significant difference of the metabolite concentration at the end of experiment was observed between KH2PO4-amended and non-amended treatments, which denoted that the addition of KH2PO4 did not reduce the formation of HTI in the longer incubation course. In BMC-amended soil, the degradation rate was about 1.8 times faster than in non-amended soil. At 30 days of incubation, both chlorothalonil and HTI were degraded to a lower level in BMC-amended soil than in non-amended soil. The application of farm litter is a common fertilizing practice in vegetable fields in China, and thus this practice could not only improve soil fertility but also promote the removal of chlorothalonil and its metabolite HTI to further increase safety in crop rotations.
Keywords: 4-OH-chlorothalonil (HTI), KH2PO4, Bovine manure compost (BMC)
ISI Document Delivery No.: 400ZA

1455. Wang, J.; Timchalk, C., and Lin, Y. H. Carbon nanotube-based electrochemical sensor for assay of salivary cholinesterase enzyme activity: An exposure biomarker of organophosphate pesticides and nerve agents. 2008; 42, (7 ): 2688-2693.


Rec #: 71649
Keywords: IN VITRO
Notes: Chemical of Concern: CPY
Abstract: Abstract: Certain saliva enzymes may be useful biomarkers for detecting exposures to organophosphate pesticides and chemical nerve agents. In this regard, saliva biomonitoring offers a simple and noninvasive approach for rapidly evaluating those exposures in real time. An electrochemical sensor coupled with a microflow injection system was developed for a simple, rapid, and sensitive characterization of cholinesterase (ChE) enzyme activities in rat saliva. The electrochemical sensor is based on a carbon nanotube (CNT)-modified screen-printed carbon electrode (SPE), which is integrated into a flow cell. Because of the excellent electrocatalytic activity of the CNTs, the sensor can detect electroactive species that are produced from enzymatic reactions with extremely high sensitivity and at low potentials. The electrochemical properties of acetylcholinesterase (AChE) enzymatic products were studied using a CNT-modified SPE, and the operation parameters such as the applied potential and substrate concentration were optimized to achieve the best performance. The AChE enzyme activity was further investigated using the CNT-based electrochemical sensor with commercially available purified AChE and ChE in saliva obtained from nave rats. It is found that the calibration curve is linear over a wide range of AChE concentrations from 5 pM to 0.5 nM, and the sensor is very sensitive with the detection limit down to 2 pM. The dynamics of the ChE enzyme activity in saliva with organophosphate pesticides was further studied using this sensor. The results show that the senor can be used to characterize salivary enzyme activity and to detect the exposure to organophosphate compounds.
1   ...   131   132   133   134   135   136   137   138   ...   151


The database is protected by copyright ©dentisty.org 2016
send message

    Main page