Preparation of antibodies and development of an enzyme immunoassay for determination of atrazine in environmental samples

An indirect competitive enzyme-linked immunosorbent assay (ELISA) has been developed and optimized for atrazine determination in soil at different depths (0–10, 10–20, and 20–30 cm) before and after 48 h of application, corn shoot and cow milk samples collected from Dina farm, Egypt. This assay was based on a specific polyclonal antibodies (PAb) raised by immunizing New Zealand rabbits with an immunogen prepared by coupling 3-{4-(ethylamino)-6-(isopropylamino)-1,3,5-triazine-2-yl} thiopropanoic acid to bovine serum albumin (BSA) via N-hydroxysuccinimide (NHS) active ester method. The sensitivity (estimated as IC₅₀value) was 17.5 μg mL^?1 with a detection limit of 0.1 ng mL^?1. The maximum atrazine concentration was found in soil especially in the deepest layer (325 and 890 μg kg^?1 before and after application, respectively). Atrazine concentration in corn shoot was 333.28, μg kg^?1 dry plant, while there was no detectable amount in milk. All samples screened by ELISA were validated by gas chromatography mass spectrometer procedure (GC/MS). Good correlation was achieved between the two methods (r = 0.997 for soil and 0.9814 for plant). This study demonstrates the utility and convenience of the simple, practical and cost–effective ELISA method in the laboratory for analysis of environmental samples. The method is ideal for the rapid screening of large numbers of samples in laboratories where access to GC/MS facilities, is limited or lacking.     

Determination of atrazine in rainfall and surface water by enzyme immunoassay

Rainwater and surface water from four sites in Germany (Bavaria and Lower Saxony) were analyzed for atrazine by enzyme immunoassay from June 1990 until October 1992. The limit of quantification of the immunoassay was 0.02 μg/L with a middle of the test at 0.2 μg/L. About 60 % of the samples contained measurable amounts of atrazine. Seasonal trends were observed, with the highest concentration in the summer months of up to 4 μg/L for rainwater and up to 15 μg/L for surface waters. The highest concentrations were found in agricultural areas, while in the investigated national parks up to 0.56 μg/L could be detected in rain water. This points to long-range atmospheric transport from agricultural areas to pristine national parks. Samples from forest stands usually showed higher atrazine concentrations than samples from open fields. Deposition rates of 10 – 50 μg/m² · yr were observed in the national parks and 10–180 μg/m² · yr at the agricultural sites. Comparison of results obtained by enzyme immunoassay and GC/MS showed a good correlation of r = 0.95.     

Development of an enzyme-linked immunosorbent assay for atrazine monitoring in water samples

The implementation of the Water Framework Directive (2000/60/EC) requires the establishment of monitoring programs. However, conventional procedures for sample preparation prior to chromatographic analysis are rather expensive and time consuming, being the development of cost-effective and easy tool a necessity. The aim of this work was to develop an enzyme-linked immunosorbent assay (ELISA) able to determine atrazine in water samples. Matrix effects evaluation showed that the increase of humic acid (HA) concentration leads to flattened calibration curves and to the loss of the sigmoidal shape. However, such interference was overcome, by the presence of an environmental sample buffer, incubated together with the samples. Recoveries from 88.5 to 119.2 % were obtained in the presence of HA concentrations up to 20 mg?L^?1. An analytical range from 0.003 to 1 μg?L^?1 was obtained, and atrazine was detected in a sewage treatment plant with concentrations ranging from 14 to 52 ng?L^?1.     

A new enzyme immunoassay for PCDD/F TEQ screening in environmental samples: comparison to micro-EROD assay and to chemical analysis.

A new Enzyme ImmunoAssay (EIA) for PCDD/F TEQ measurement in extracts of environmental samples was described. The bioassay TEQ which derived from EIA and EROD were compared with each other and with results from chemical analysis. For all environmental samples, the EROD-TEQ is higher than the value from chemical analysis. However, the EIA-TEQ is much more identical with the value from chemical analysis. Our results indicate that the EIA assay is a complementary method to the EROD assay and should be useful as a rapid and sensitive screening tool for environmental samples in many situations.     

Production of a monoclonal antibody and development of an immunoassay for detection of Cr(III) in water samples

In this study we report the production of a monoclonal antibody (Mab) specific for Cr(III)-chelate and the development of a competitive immunoassay for detection of Cr(III) in water samples. In the assay, the complete antigen (Cr(III)-ITCBE-BSA) was used as coating antigen, and Cr(III)-ITCBE as competitor competes with coating antigen to bind with Mab. Using this approach, the spiked water samples with Cr(III) were detected. The linear range of the detection was 0.7–12.4 ng mL⁻¹. The limit of the detection (LOD) was 0.51 ng mL⁻¹. The spiked results were also confirmed by ICP-MS, which showed a good correlation (R² = 0.997) between the two methods. The results indicated that the developed assay was reliable and suitable for the detection of Cr(III) in water samples.     

Literature survey of on-line spectroscopic methods for lead determination in environmental solid samples

A review is presented where are shown the advantages involved in the use of flow injection (FI) analysis for the determination of lead in environmental solid samples by spectroscopic detectors. The FI methods proposed for the determination of lead in these samples are described and compared according to the detection technique used. Analytical data of interest and interferences are discussed for each technique.     

Evaluation of atrazine positive and false positive immunoassay detections in ground water

Abstract

False positive responses on an atrazine (6‐chloro‐N‐ethyl‐N'‐(l‐methylethyl)‐1, 3, 5‐triazine‐2, 4‐diamine) immunoassay kit were investigated to explain possible causes for these occurences. Ground water samples were evaluated with the immunoassay kit and positive responses (>0.20 μg L^‐1) were confirmed using gas chromatography/mass spectrometry (GC/MS). Non‐confirming samples (false positives) were analyzed for seven additional compounds on GC. Resulting GC/MS and GC analyses showed that 70% of the false positives could be attributed to two compounds. Prometon (6‐methoxy‐N,N'‐bis(l‐methylethyl)‐1, 3, 5‐triazine‐2, 4‐diamine) was responsible for the majority (64%) of the false positive responses The atrazine metabolite, deethylatrazine (2‐chloro‐4‐amino‐6‐isopropylamino‐1, 3, 5‐triazine), was responsible for the other 6% of the false positives measured. Unattributed false positives (30%) were probably due to an overestimation of pesticide concentrations in the kit's lower detection range.     

Electrochemical study of the fungicide acibenzolar-s-methyl and its voltammetric determination in environmental samples

The electrochemical behavior of new generation fungicide acibenzolar-s-methyl (S-methyl 1,2,3-benzothiadiazole-7-carbothioate, ASM) on the hanging mercury drop electrode (HMDE) was investigated using square wave adsorptive stripping voltammetry. This method of determination is based on the irreversible reduction of ASM at the HMDE. The well-defined ASM peak was observed at ?0.4 V (vs. Ag/AgCl) in BR buffer at pH 2.2. The reduction peak current was proportional to concentration of ASM from 1.0 × 10^?8 to 6.0 × 10^?8 mol L^?1 with detection and quantification limit 3.0 × 10^?9 and 1.0 × 10^?8 mol L^?1, respectively. The applicability of the developed method for analysis of spiked samples of tap water, river water, and soil is illustrated. The effect of adsorption on the mercury electrode was studied in detail using the AC impedance method. Possible interferences with other common pesticides and heavy metal ions were examined. Clarification of the electrode mechanism was made using cyclic voltammetry (CV) technique.     

Evaluating the environmental fate of atrazine in France

Atrazine is used in large quantities in U.S. and European countries as a weed-control agent. As a result, numerous data on its environmental fate and hazards have been published. Analysis of the literature shows that this herbicide can be found with appreciable concentrations in groundwaters, rivers, lakes, and estuaries. This contamination principally results from leaching and runoff processes. Atrazine can also pollute fog and rain due to its release into the atmosphere through spray applications. This large amount of information constitutes a very attractive basis for assessing the simulation performances of environmental fate models. In this context, CHEMFRANCE, a regional fugacity model level III which calculates the environmental distribution of organic chemicals in twelve defined regions of France has been used to estimate the environmental fate of atrazine. The calculated values are comparable with field and laboratory results. Therefore, CHEMFRANCE can be considered as a useful tool for simulating the environmental fate of this agrochemical.     

环境中芳香胺类化合物的色谱检测方法研究进展

芳香胺类化合物具有致癌和致突变的作用, 是环境优先控制污染物之一。芳香胺类化合物的检测方法很多,其中,色谱法具有分析速度快、 线性范围宽、 响应灵敏和检出限低的特点, 是目前检测环境中芳香胺类化合物的常用方法。对水、土壤和大气三类不同环境样品中芳香胺类化合物的色谱检测方法进行了现状分析,论述了色谱检测方法的研究进展,并对今后的研究趋势进行了展望。     

Development of enzyme immunoassay for detection of DDT

Dichlorodiphenyltrichloroethane (DDT) is one of the persistent organic pollutants (POPs) widely found in the environment and in the general population. In this study, a direct competitive enzyme immunoassay (EIA) has been developed for the quantitative analysis of DDT. To generate a specific polyclonal antibody for EIA, p, p′-DDT was conjugated to porcine thyroglobulin for rabbit immunization. At optimized EIA conditions, the standard curves ranged from 0.137 to 100 ng/mL with the quantification limit of 0.41 ng/mL. The coefficients of variation (CV%) were 5.42–10.53% for intra-assay and 6.04–7.26% for inter-assay. Cross-reactivities with DDT metabolites (DDTs, including o, p′-DDT, p, p′-DDD, o, p′-DDD, p, p′-DDE, o, p′-DDE, p, p′-dichlorobenzophenone (DCBP), o, p′-DCBP) were investigated. The polyclonal antibody showed relatively low and/or no cross-reactivity with these compounds, and the assay was seen to be highly selective for p, p′-DDT. Moreover, the DDTs could be ranked by their reactivity: DDT > DDD > DDE > DCBP. In addition, the characterization of the polyclonal antibody indicated that the antiserum possesses a high specificity for p, p′-isomers. The results indicated that the developed EIA using this antibody could be a convenient and supplemental analytical tool for monitoring DDT.     

Development of enzyme immunoassay for detection of DDT

Dichlorodiphenyltrichloroethane (DDT) is one of the persistent organic pollutants (POPs) widely found in the environment and in the general population. In this study, a direct competitive enzyme immunoassay (EIA) has been developed for the quantitative analysis of DDT. To generate a specific polyclonal antibody for EIA, p, p'-DDT was conjugated to porcine thyroglobulin for rabbit immunization. At optimized EIA conditions, the standard curves ranged from 0.137 to 100 ng/mL with the quantification limit of 0.41 ng/mL. The coefficients of variation (CV%) were 5.42-10.53% for intra-assay and 6.04-7.26% for inter-assay. Cross-reactivities with DDT metabolites (DDTs, including o, p'-DDT, p, p'-DDD, o, p'-DDD, p, p'-DDE, o, p'-DDE, p, p'-dichlorobenzophenone (DCBP), o, p'-DCBP) were investigated. The polyclonal antibody showed relatively low and/or no cross-reactivity with these compounds, and the assay was seen to be highly selective for p, p'-DDT. Moreover, the DDTs could be ranked by their reactivity: DDT > DDD > DDE > DCBP. In addition, the characterization of the polyclonal antibody indicated that the antiserum possesses a high specificity for p, p'-isomers. The results indicated that the developed EIA using this antibody could be a convenient and supplemental analytical tool for monitoring DDT.     

15N Metabolic test for the determination of phytotoxic effects of chemicals and contaminated environmental samples

A stable isotope¹⁵N-nitrogen test (ESIMA = Ecotoxicological Stable Isotope Metabolic Assay) was developed to assess biological effects and the potential toxicological hazard of chemicals and contaminated environmental samples on plant metabolism. The assay measures the effect of toxicants on the incorporation of a¹⁵N labelled tracer into the total nitrogen fraction (both the nonprotein and protein fraction) of plants. Segments ofPisum arvense epicotyls are used as test substrates because of their high metabolic activity. The plant material is incubated under standardised conditions for two hours; subsequently¹⁵N incorporation is analysed by determining the¹⁵N abundance (¹⁵N atom-%) in the epicotyl segments. The effects of toxicants are evaluated by comparing the¹⁵N incorporation rates of control tissue and epicotyl segments exposed to individual chemicals or complex environmental samples. The specificity and sensitivity of effects as indicated by ESIMA were compared with effects as measured by two established ecotoxicological bioassays, the pollen tube growth test using pollen ofNicotiana sylvestris and the bacterial luminescence inhibition test using pollen ofPhotobacterium phosphoreum. The results of the study clearly indicate the suitability of ESIMA for assessing toxic impacts on plant nitrogen metabolism. Prof. Dr. habil. Hans Faust dedicated to his 70^th birthday.     

阿特拉津在土壤中的环境行为研究进展

概述了阿特拉津在土壤中的迁移、降解及其对植物的影响等环境行为,阐述了土壤组成、土壤pH值以及温度、湿度等因素对各种环境行为过程的影响,并结合目前国内外的研究现状,提出了阿特拉津环境行为新的研究方向。     

Monoclonal antibody produced by heterologous indirect enzyme-linked immunosorbent assay and its application for parathion residue determination in agricultural and environmental samples

A heterologous indirect enzyme-linked immunosorbent assay (ELISA) was developed, which was based on monoclonal antibody (Mab) to determine parathion residue in agricultural and environmental samples. Eight Mabs were produced by introducing the heterologous indirect ELISA into the screening procedure. It was shown that these Mabs had more broad-reactivity with twenty competitors than that of 5H7 (Mab produced by homologous screening). So it became much easier using these new Mabs to develop heterologous immunoassays. In addition, all the developed heterologous ELISAs could be used to determine parathion residue in semiquantitative or quantitative level, and their detection limitation (LOD) was around 2 ng/mL. Compared with the previous heterologous ELISA (hapten 11/5H7) with IC₅₀ of 13.3 ng/mL, a better heterologous ELISA (hapten 11/1E1) was obtained with IC₅₀ of 3.8 ng/mL, which improved the sensitivity 3.5 times. Finally, the latter was applied to parathion residue determination in spiked agricultural and environmental samples without extraction or cleanup. The average recoveries of parathion added to water, soil, cucumber, Chinese cabbage and carrot were between 80.4 % and 111.8 %. The LOD for water and soil samples was 5 ng/mL, and the LOD for cucumber, rice and corn samples was 10 ng/mL.     

The determination of toxaphene in environmental samples by negative ion electron capture high resolution mass spectrometry

A method is described for the analysis of toxaphene in environmental samples by high resolution gas chromatography high resolution mass spectrometry in selected ion electron capture negative ion mode. Toxaphene is detected by monitoring [M-Cl]- fragments ions of chlorobornanes (Cl6-Cl10) and chlorobornenes (Cl6-Cl7) using formal ion ratio criteria. The method shows high sensitivity and excellent specificity for the detection of chlorobornanes with negligible interference from of a wide range of common environmental organochlorines including chlordanes, PCBs and PCB-oxygen adducts. The analytical scheme is applicable to sediment and biological tissue samples and typically provide sample detection limits of less than 0.2 ng/g technical toxaphene for a 10 g sample.     

Cloud point extraction for the preconcentration of palladium and lead in environmental samples and determination by flow injection flame atomic absorption spectrometry

Purpose

An online cloud-point extraction (CPE) coupled with flow injection method is developed for the separation and preconcentration of palladium and lead from various matrices using flame atomic absorption spectrometry (FAAS).

Method

The method employs the formation of complexes of the metallic species with dimethylglyoxime, which are subsequently entrapped in the micelles of the surfactant Triton X-114, upon increase of the solution temperature to 60°C and loaded into the flow injection system at a flow rate of 4.6?mL?min^?1. The surfactant rich-phase was retained in a minicolumn packed with animal wool at pH?6 and eluted with 1.0?mol?L^?1 nitric acid in methanol at a flow rate of 1.1?mL?min^?1 directly into the nebulizer of the FAAS. The CPE variables and flow injection conditions affecting the analytical performance of the combined methodology was studied and optimized.

Results

Under the optimized conditions for 25?mL of preconcentrated solution, the enrichment factors were 51 and 44, and the limit of detections were 1.0 and 1.4?ng?mL^?1 for palladium and lead, respectively. Finally, the developed method was applied for the determination of palladium and lead in street dust, soil, radiology waste, catalytic converter, and urban aerosol samples.

Conclusions

Cloud-point extraction coupled with flow injection-FAAS was proposed as an effective preconcentration and separation method for Pd and Pb determination in radiology waste, road dust, soil, and urban aerosol samples. The most favorable feature of this method is its much higher selectivity, sensitivity, rapidity, good extraction efficiency, and employs the green chemistry concept, as it does not require the addition of toxic chemicals. In addition, this proposed method gives very low detection limits and good relative standard.     

Analytical methods for the determination of alachlor, metolachlor, simazine and atrazine mobility in soils

A method for the determination of the mobility of the herbicides, alachlor, metolachlor, simazine and atrazine in soil is described. The method is based on the use of soil thin-layer chromatography (TLC) and does not require the use of radiolabelled compounds. Soil on the TLC plate after development was separated into various bands, the material in each band was extracted with solvents and analyzed by gas chromatography.