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1.
《Analytical letters》2012,45(3):515-525
ABSTRACT An amperometric immunosensor for the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in water has been developed using sequential injection analysis techniques. The system is based on a rapid competitive enzyme immunoassay employing an alkaline phosphatase-labeled monoclonal antibody directed against the herbicide and an immunoreactor with 2,4-D immobilized via bovine serum albumin either to Eupergit in a column or directly to the surface of a glass capillary. The detection limit of the immunosensor at 0.1 μg 2,4-D/l without enrichment of the analyte makes automatic measurements of 2,4-D in drinking and ground water feasible. 相似文献
2.
B. B. Dzantiev A. V. Zherdev O. G. Romanenko L. A. Sapegova 《International journal of environmental analytical chemistry》2013,93(1-4):95-111
Abstract Different ELISA techniques have been developed for the detemination of four widely used pesticides: 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), simazine and atrazine. Dependences between the assay scheme and the limiting detectable concentration of the pesticide were studied. The cases of preferential applying of the scheme with immobilized antibodies or one with immobilized pesticide-protein conjugate have been revealed. The following approaches resulting in lowering of ELISA sensitivity were proposed: preliminary incubation of the tested sample with antibodies, immobilization of antibodies via staphylococcal protein A, usage of monovalent fragments of antibodies instead of native ones and chemical modification of the pesticide molecules in the sample. Optimal combinations of these approaches permitted to lower the detection limit of the assays in about 5–30 times. The achieved sensitivities were 3 ng/mL for 2,4-D, 5 ng/mL for 2,4,5-T, 0.05 ng/mL for simazine, and 0.1 ng/mL for atrazine, being acceptable for purposes of ecological monitoring. 相似文献
3.
Development of a dipstick immunoassay for quantitative determination of 2,4-dichlorophenoxyacetic acid in water, fruit and urine samples 总被引:1,自引:0,他引:1
N. V. Cuong T. T. Bachmann R. D. Schmid 《Fresenius' Journal of Analytical Chemistry》1999,364(6):584-589
A sensitive dipstick assay for 2,4-dichlorophenoxyacetic acid (2,4-D) detection was developed. The assay was based on the
competitive reaction of 2,4-D and enzyme tracer with monoclonal antibodies immobilised on an Ultrabind? membrane. The binding of enzyme tracer on the test strip was determined by a simple, portable reflectometer as remission
at 657 nm. Using this technique, 2,4-D could be detected in a concentration range of 0.5 μg/L to 100 μg/L. The center point
of the 2,4-D test was found at a concentration of 6 μg/L. Cross-reactivity with 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)
as determined by this dipstick assay was 2.5% and 3% by standard ELISA technique using microtiter plates. The assay was applied
in the detection of 2,4-D in real water samples, and sensitivity was comparable to spiked water samples. If combined with
an effective extraction procedure that results in recovery rates of 90%, the dipstick assay can be used to monitor human exposure
to 2,4-D from contamination in water, from oranges and in testing urine samples.
Received: 2 September 1998 / Revised: 29 January 1999 / Accepted: 31 January 1999 相似文献
4.
《Analytical letters》2012,45(15):2983-2995
Abstract An immunosensor method for determination of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was developed. It is based on the use of the competition between 2,4-D in analyzed probes and 2,4-D-peroxidase conjugate for binding with antibodies being immobilized on porous photo-activated cellulose membranes. These membranes were attached to the gate region of pH-sensitive field transistor (FET) and electrochemical detection of enzyme activity was carried out. Mixture of ascorbic acid (0.1 mM), o-phenylenediamine (1.0 mM), hydrogen peroxide (1.0 mM) was used as substrate solution. The initial rate of pH-shift of the FETs gate region was recorded as measured parameter. The developed system permits to determine 2,4-D in water solutions for concentrations down to 1 ng/ml. This portable and inexpensive immunosensor meets modern requirements as analytical system for ecological monitoring. 相似文献
5.
Determination of 2,4-D and Dicamba in food crops by MEKC 总被引:2,自引:0,他引:2
Summary The determination of 2,4-D (2,4-dichlorophenoxyacetic acid) and Dicamba (2-methoxy-3,6-dichlorobenzoic acid) residues in sugar
cane, rice and corn was performed by a supercritical fluid extraction (SFE) method using CO2/acetone as extraction mix and an SFE apparatus developed in our laboratory. The extracts were cleaned up after extraction
by both liquid-liquid partition and a Florisil column. Micellar electrokinetic capillary chromatography (MEKC) coupled with
ultraviolet on-column detection was used for the analysis of these pesticides. The detection limits were improved by the preparation
of a special detection cell with an increased pathlength that gave detection limits of ca. 0.6 pg for 2,4-D and Dicamba. Our
results demonstrated that capillary electrophoresis can be a powerful new analytical tool for pesticide residue analysis. 相似文献
6.
《液相色谱法及相关技术杂志》2012,35(7):1563-1576
Abstract Salt formulations of 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) and dichlorprop [2-(2,4-dichlorophenoxy)propanoic acid] have been analysed by reversed-phase HPLC using a C18-column with 50:50 (v/v) acetonitrile/2% acetic acid as eluant. Internal and external standard HPLC methods are compared. Ester formulations of 2,4-D and 2,4,5–T are analysed, without hydrolysis, on the same column using 60:40 (v/v) acetonitrile/2% acetic acid as eluant. The method has been used in this laboratory to determine free phenoxy acid in ester formulations, and for the identification of esters in mixed ester formulations. The methods are fast and accurate, and offer some advantages over previously-described methods. 相似文献
7.
Michael A. Quilliam P. Greig Sim Archibald W. McCulloch A. Gavin McInnes 《International journal of environmental analytical chemistry》2013,93(3):139-154
Abstract A recent outbreak of poisoning resulting from the consumption of cultured blue mussels (Mytilus edulis L.) from a localized area in Eastern Canada has been attributed to the presence of domoic acid (1), a relatively rare neurotoxic amino acid, previously found only in some algae of the family Rhodomelaceae. Studies on aqueous extracts of shellfish tissue indicated that the toxin and several of its isomers could be separated (and isolated in sufficient amounts for subsequent structural identification) by reversed-phase high-performance liquid chromatography (HPLC) with ultraviolet (UV) diode array detection (DAD). Aqueous acetonitrile containing 0.1% v/v trifluoroacetic acid was used as mobile phase. As the retention time and characteristic UV absorption spectrum of 1 (λmax = 242 nm) permit unequivocal identification, the HPLC-DAD procedure was refined with a microbore column to provide a rapid (5 min), sensitive (0.3 ng detection limit) and reproducible assay method for the determination of 1 in shellfish tissue. Extraction was accomplished by boiling homogenized shellfish tissue for 5 min with distilled water. Extracts were taken through an octadecylsilica solid phase extraction clean-up prior to HPLC. This method has been applied to a variety of shellfish and phytoplankton samples. BRIEF Reversed-phase HPLC with ultraviolet diode array detection was used to analyze shellfish tissue and phytoplankton extracts for domoic acid. A rapid (5 min) and sensitive (0.3 ng detection limit) assay is presented. 相似文献
8.
S. A. Popov Yu. A. Chumichkina E. N. Shapovalova S. G. Dmitrienko Yu. A. Zolotov 《Journal of Analytical Chemistry》2011,66(1):6-10
The potency of molecularly imprinted polymers (MIP) for 2,4-dichlorophenoxyacetic acid (2,4-D) in the dynamic sorption preconcentration (solid phase extraction) of 2,4-D and three other structurally related species
(2,4-dichlorophenol, 2-chlorophenol, and dikamba) from aqueous solutions is assessed. The optimal conditions for preconcentration
are found: 0.01 M HCl, 25–100 mL of solution, flow rate of solution 0.7 mL/min, column (15 × 2.7 mL), and sorbent weight 0.04
g. The analytes are desorbed with 1 mL of methanol and detected in the eluate by reversed-phase HPLC with spectrophotometric
detection at 225 nm. The detection limit for 2,4-D makes 0.4 μg/mL without preconcentration and 0.01 μg/mL with preconcentration
from a volume of 100 mL. The procedure is applied to the analysis of model mixtures based on fresh river water. 相似文献
9.
A novel immunoassay format employing direct coating of small molecular hapten on microtiter plates is reported for the detection of atrazine and 2,4-dichlorophenoxyacetic (2,4-D). In this assay, the polystyrene surface of microtiter plates was first treated with an acid to generate -NO2 groups on the surface. Acid treated plates were further treated with 3-aminoprpyltriethoxysilane (APTES) to functionalize the plate surface with amino groups for covalent linkage to small molecular hapten with carboxyl groups. The modified plates showed significantly high antibody binding in comparison to plates coated with hapten-carrier protein conjugates and presented excellent stability as a function of the buffer pH and reaction time. The developed assay employing direct hapten coated plates and using affinity purified atrazine and 2,4-D antibodies demonstrated very high sensitivity, IC50 values for atrazine and 2,4-D equal to 0.8 ng mL−1 and 7 ng mL−1, respectively. The assay could detect atrazine and 2,4-D levels in standard water samples even at a very low concentration upto 0.02 and 0.7 ng mL−1 respectively in the optimum working range between 0.01 and 1000 ng mL−1 with good signal reproducibility (p values: 0.091 and 0.224 for atrazine and 2,4-D, respectively). The developed immunoassay format could be used as convenient quantitative tool for the sensitive screening of pesticides in samples. 相似文献
10.
Electrochemical determination of 2,4-D at a mercury electrode 总被引:1,自引:0,他引:1
An indirect electrochemical determination of 2,4-dichlorophenoxyacetic acid (2,4-D), has been presented. The method is based on the adsorption and desorption of 2,4-D on mercury electrode. Also, the electrochemical behavior of 2,4-D in aqueous solutions at different pH values and different 2,4-D concentrations were studied. A simple and rapid method has been developed for its extraction from water and soil. The subsequent determination was carried out by a tensammetric method. Three calibration curves could be obtained from different parts of voltammogram. Under the optimum conditions (pH = 2.3; Eacc = −1100 mV; tacc = 60 s; alternative current mode; ν = 40 mV s−1; pulse height = 20 mV; modulation frequency = 60 Hz; phase angle = 90°) the limit of detection was 50 μg L−1. The proposed method was applied to the determination of 2,4-D in real samples such as soil and water. 相似文献
11.
《Analytical letters》2012,45(8):1475-1487
Abstract A microprocessor controlled piezoelectric detector as sensor was employed to monitor in real time protein adsorption and immunoreactions using piezoelectric quartz crystals (AT-cut) with a basic resonant frequency of 10 MHz. The adsorbed protein was an immunoglobulin (h-lg G); in the immunosensing a covalent immobilized molecule (the pesticide 2,4-D) formed the receptor for the immobilized ligand sample (Mab anti-2,4-D) in a competitive assay. 相似文献
12.
Electrochemical sensor for 2,4-dichlorophenoxy acetic acid using molecularly imprinted polypyrrole membrane as recognition element 总被引:1,自引:0,他引:1
An electrochemical sensor based on molecularly imprinted polypyrrole membranes is reported for the determination of 2,4-dichlorophenoxy acetic acid (2,4-D). The sensor was prepared by electropolymerization of pyrrole on a glassy carbon electrode in the presence of 2,4-D as a template. The template was removed by overoxidation at +1.3 V in buffer solution. The sensor can effectively improve the reductive properties of 2,4-D and eliminate interferences by other pesticides and electroactive species. The peak current at -0.78 V is linear with the concentration of 2,4-D from 1.0 to 10 µM, the detection limit is 0.83 µM (at 3σ), and the relative standard deviation is 3.9% (at 5.0 µM of 2,4-D; n?=?7). The method has been successfully applied to the determination of 2,4-D in environmental water samples, with recovery rates ranging from 92% to 108%. 相似文献
13.
We present a novel immunoassay format utilizing the catalytic properties of gold nanoparticles in the luminol-silver nitrate-gold nanoparticle based chemiluminescence (CL) system for the detection of widely used herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Highly sensitive anti-2,4-D antibody was produced and conjugated with gold nanoparticles of various sizes. In the present assay format, employing a competitive inhibition approach, a well-characterized hapten-protein conjugate (2,4-D-BSA) was used to coat the microtiter plates. The analyte (2,4-D) was pre-incubated with anti-2,4-D antibody labeled with gold nanoparticles and added to each well of the microtiter plate. The gold label triggered the reaction between luminol and silver nitrate generating a luminescence signal at 425 nm. Under the optimized conditions, the CL based immunoassay showed the detection limit of 2,4-D in standard water samples around 3 ng mL(-1). The CL based immunoassay format, based on gold nanoparticles as a catalyst, could be used as a fast screening methodology (<30 min) for pesticide detection. 相似文献
14.
Off-line SFE-CGC-ECD analysis of 2,4-D and Dicamba residues in real sugar cane,rice and corn samples
Fernando M. Lanas Sandra R. Rissato Antonio A. Mozeto 《Journal of separation science》1996,19(10):564-568
Determination of 2,4-D (2,4-dichlorophenoxyacetic acid) and Dicamba (2-methoxy-3,6-dichlorobenzoic acid) residues in sugar cane, rice, and corn was carried out both by solid liquid extraction (SLE), as already described in the literature, and by a supercritical fluid extraction (SFE) method developed in our laboratory. The extracts were esterified and cleaned-up by passing through a Florisil column. Extracts were analyzed by high resolution gas chromatography, with electron capture detection. The tested methods presented good recoveries (above 90%); the SFE CO2/acetone method showed better extraction efficiencies (extracted 30 % more herbicide in real samples), shorter extraction time and lower organic solvent consumption than the SLE method. 相似文献
15.
Azadeh Manayi Soodabeh Saeidnia Mohammad Ali Faramarzi Nasrin Samadi Samineh Jafari Mahdi Vazirian Ardeshir Ghaderi Tahmineh Mirnezami Abbas Hadjiakhoondi Mohammad Reza Shams Ardekani Mahnaz Khanavi 《Applied biochemistry and biotechnology》2013,170(1):176-184
In the study, anti-Candida activity and phenol contents of Lythrum salicaria L. calli and wild species have been evaluated. The seeds of L. salicaria (Lythraceae), collected from Lahidjan City in the north of Iran, were cultured in Murashige and Skoog medium (MSM) with a supplement, gibberellin, to germinate. Callus inductions were performed from segments of seedling on MSM containing different concentrations of plant growth regulators, 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The activity of calluses extracts, wild plant, gallic acid, and 3,3′,4′-tri-O-methylellagic acid-4-O-β-d-glucopyranoside (TMEG) as the main phenolic compounds against Candida albicans was assessed using cup plate diffusion method. The total phenols contents of calli and wild plant extracts were analyzed using Folin–Ciocalteu reagent. The callus formation in MSM supplemented with various concentrations of 2,4-D and BAP were 0–100 %. Anti-Candida activity of callus extract which obtained from MSM supplemented with 2,4-D and BAP (1 mg?dm?3) was similar to the wild plant extract. Minimum inhibitory concentration values of gallic acid and TMEG were obtained as 0.312 and 2.5 mg?cm?3, respectively. Gallic acid equivalent values in all treatments were from 0 to 288 μg GAE mg?1. Phenolic contents of plant aerial parts (331?±?3.7 μg GAE mg?1) and the callus, which developed in MSM including 1 mg?dm?3 of both 2,4-D and BAP, showed the same phenolic value and exhibited anti-Candida extract activity. 相似文献
16.
Sakamoto S Pongkitwitoon B Nakamura S Sasaki-Tabata K Tanizaki Y Maenaka K Tanaka H Morimoto S 《Applied biochemistry and biotechnology》2011,164(6):715-728
A single-chain variable fragment antibody against herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D-scFv) has been successfully
expressed in the hemolymph of silkworm larvae using a rapid Bombyx mori nucleopolyhedrovirus (BmNPV) bacmid DNA system. Variable heavy- and light-chain domains were cloned directly from the cDNA
of the hybridoma cell line 2C4 and assembled together with flexible peptide linker (Gly4Ser)3 between two domains. The yield of functional 2,4-D-scFv after purification was 640 μg per 30 ml of hemolymph, which is equivalent
to 21.3 mg per liter of hemolymph. The characterization of 2,4-D-scFv using an indirect competitive enzyme-linked immunosorbent
assay (icELISA) revealed that it has wide cross-reactivities against 2,4,5-trichlorophenoxyacetic acid (65.5%), 2,4-dichlorophenol
(47.9%), and 2,4-dichlorobenzoic acid (26.0%), making it possible to apply 2,4-D-scFv to icELISA for detecting/determining
2,4-D and its metabolites. Judging from its cost and time requirements and its ease of handling, this BmNPV bacmid DNA expression
system is more useful for expressing functional scFv than bacterial systems, which frequently require costly and time-consuming
refolding. 相似文献
17.
Boris B. Kim Eugenii V. VlasovPeter MietheAlexey M. Egorov 《Analytica chimica acta》1993,280(2):191-196
An immunoaffinity chromatographic (IC) method for the determination of 2,4-dichlorophenoxyacetic acid (2,4-D) and atrazine was developed. The sensitivity was 1 and 0.1 μg l−1 for 2,4-D and atrazine, respectively, the relative standard deviation was in the range 3–8% and the total assay time per samples was 10 min. IC was combined with three detection systems: spectrophotometric, chemiluminescence and fluorescence. The whole procedure can be fully automated and applied to the quasi-continuous control of pesticide contamination and a rapid assay under out-of-laboratory conditions. 相似文献
18.
Gülsen Tel-Çayan Akhtar Muhammad Mehmet Öztürk Achyut Adhikari Aziz Türkoğlu 《Natural product research》2016,30(20):2258-2264
Phytochemical investigation of the Rhizopogon luteolus Fr. led to the isolation of one new fatty acid ester, 3-hydroxy-2,4-dimethylheptacosyl acetate (1) together with two known compounds tetracosanoic acid (2) and ergosterol (3). 1D and 2D NMR, and MS techniques were used for structural elucidation. Phenolic and fatty acid compositions were identified using HPLC–DAD and GC–MSD, respectively. Fumaric acid was the major phenolic acid, whereas linoleic, stearic and oleic acids were the most abundant fatty acids. Antioxidant and anticholinesterase activities of the extracts and compounds (1–3) were tested spectrophotometrically. Among the extracts, hexane extract showed the highest activity in all tests, particularly in β-carotene-linoleic acid assay (IC50: 16.65 ± 1.12 μg/mL). Furthermore, compound 3 exhibited higher antioxidant and anticholinesterase activities. The study indicates that R. luteolus can be used in food, cosmetic and pharmaceutical industries. 相似文献
19.
Chlorophenoxycarboxylic acid herbicides were separated and determined by capillary electrophoresis. An analysis of a six-component mixture containing 2,4-dichlorophenoxybutyric (2,4-DB), 2,4-dichlorophenoxypropionic (2,4-DP), 2,4,5-trichlorophenoxyacetic (2,4,5-T), 2,4-dichlorophenoxyacetic (2,4-D), and phenoxyacetic (PA) acids and 2,4-dichlorophenol (2,4-DCP), the product of their degradation in aqueous media, took no longer than 15 min. Solid-phase extraction on Diapak C-16 cartridges was used for sample preparation. The detection limits for herbicides in water samples with account for preconcentration (K = 250) were found to be 0.0005 mg/L for 2,4-DB, 2,4-DP, 2,4,5-T, and 2,4-D and 0.001 mg/L for PA. It was shown that humic acids (< 50 mg/L) do not interfere with the determination of chlorophenoxycarboxylic acids. 相似文献
20.
《Analytical letters》2012,45(13-14):1421-1433
Abstract Amides of 14 carboxylic acid herbicides were prepared by reacting the free acid with the amine in toluene for 1 hr at 80[ddot]C in the presence of PCl3 or P2I4. The acids include phenoxyacetic acids, arylacetic acids, and benzoic acids. Aniline, o-toluidine, 3,5-bis(trifluoromethyl)aniline, piperidine, and tetrahydroquinoline were the amine components. Excess of reagents and by-products of the reaction were removed by partitioning into aqueous acid and base. Retention times relative to 2,4-D anilide on 1% OV-22 and FSOT RSL-150 columns are listed for the anilides and should be useful for confirmation purposes. The anilides of 2,4-D, silvex and 2,4,5-T were obtained in better than 90% yield. 相似文献