Automated Analytical System for Phenols Incorporated into Screening Method Suitable for Determination of 2-Methyl-4-chlorophenoxyacetic Acid and/or 2,4-Dichlorophenoxyacetic Acid Herbicide Residues in Water

1977 ◽  
Vol 60 (1) ◽  
pp. 218-223
Author(s):  
Daniel E Ott ◽  
Hakon O Friestad
Keyword(s):  
Water Samples ◽  
Methylene Chloride ◽  
Limit Of Detection ◽  
Screening Method ◽  
Colorimetric Method ◽  
Free Phenol ◽  
Chlorophenoxyacetic Acid ◽  
Water Response ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Acid Herbicides

Abstract 2-Methyl-4-chlorophenoxyacetic acid (MCPA) and 2,4-dichlorophenoxyacetie acid (2,4-D) are extracted from water with methylene chloride and are degraded when heated in the presence of pyridine hydrochloride to their corresponding phenols which are determined automatically with a modified distillation-colorimetric analyzer system. The method has been evaluated primarily with surface water samples collected from areas of known MCPA applications. The lower limit of detection of MCPA is about 50 µg/L water. Response for 2,4-D is almost identical to that for MCPA at equal concentrations. Comparative responses to other potential responding phenoxy acid herbicides have not been determined. MCPA results from this method for several water samples compared favorably with results from a gas chromatographic method. The scntiautontated colorimetric method can be applied to water samples of unknown history as a screening method in which case a significant, positive recorder response, suitably corrected for free phenol response as suggested herein, indicates probability of presence of one or more of the responding herbicides. The sample would then need to be examined by other, more definitive means.

Two Enzyme Immunoassays to Screen for 2,4-Dichlorophenoxyacetic Acid in Water

1987 ◽  
Vol 70 (5) ◽  
pp. 874-878 ◽  
Author(s):  
James Fleeker
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Dichlorophenoxyacetic Acid ◽  
Carrier Protein ◽  
Similar Response ◽  
Enzyme Immunoassays ◽  
Concentration Step ◽  
Chlorophenoxyacetic Acid ◽  
Phenoxy Herbicides ◽  
2,4 Dichlorophenoxyacetic Acid

Abstract Two solid-phase enzyme immunoassays were developed to measure 2,4-dichlorophenoxyacetic acid (2,4-D), using 2 sets of structurally distinct immunogens and enzyme ligands. The 2,4-D analog, 2-methyl- 4-chlorophenoxyacetic acid (MCPA), gave a similar response with both methods, whereas other phenoxy herbicides cross-reacted differently. In method A, the aromatic moiety of 2,4-D was distal from the carrier protein and labeled enzyme, whereas in method B, the acetic acid portion of the herbicide was distal. The use of both methods to screen for this herbicide in ground water and municipal and river water reduced the number of false-positive responses. Water sources having a low background response could be monitored with either method alone. When a concentration step, with disposable C18 extraction columns, was used, the limit of sensitivity was 5 ng/L,. Method A was the more sensitive of the 2 methods with a limit of detection of 10 j*g/L without the concentration step

Liquid Chromatographic Screening Method for Fluorescent Derivatives of Chlorophenoxy Acid Herbicides in Water

1992 ◽  
Vol 75 (4) ◽  
pp. 720-724 ◽  
Author(s):  
Toshinari Suzuki ◽  
Satoru Watanabe
Keyword(s):  
Solid Phase Extraction ◽  
Water Samples ◽  
Solid Phase ◽  
Screening Method ◽  
Ethyl Esters ◽  
Separate Determination ◽  
Phase Extraction ◽  
Liquid Chromatographic ◽  
Acid Herbicides

Abstract A liquid chromatographic method for screening 9 chlorophenoxy acids (2,4-D; 2,4-DP; 2,4-DB; MCPA; MCPP; MCPB; 2,4,5-T; 2,4,5-TP; and 2,4,5-TB) and their ethyl esters in ground- and tap water is presented. The water samples are acidified and subjected to either liquid-liquid or solid-phase extraction. The extracts obtained are saponified in 0.03N NaOH-50% methanol (1+1) and the acidic compounds are re-extracted with ethyl acetate-n-hexane (8 + 2) after acidification and derivatized with 9- anthryldiazomethane. Derivatized compounds are analyzed using reversed-phase column chromatography with fluorescence detection (excitation, 365 nm; emission, 412 nm). Recoveries of analytes from 20 mL water samples were greater than 90%, and the average coefficient of variation was within 5.0% at 0.5 ppb for both extraction methods. These methods are simple and useful for the determination of small amounts of chlorophenoxy herbicides. Solid-phase extraction is suitable for screening a large number of samples simultaneously, and liquid extraction for separate determination of the acids and ethyl esters of the herbicides was improved by introducing a saponification step.

scholarly journals Rapid Screening Method for Detecting Ethinyl Estradiol in Natural Water Employing Voltammetry

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Chalder Nogueira Nunes ◽  
Lucas Ely Pauluk ◽  
Maria Lurdes Felsner ◽  
Vanessa Egéa dos Anjos ◽  
Sueli Pércio Quináia
Keyword(s):  
Water Samples ◽  
Ethinyl Estradiol ◽  
Limit Of Detection ◽  
Screening Method ◽  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Electrochemical Process ◽  
Rapid Screening ◽  
Relative Standard ◽  
Pharmaceutically Active Compound

17α-Ethinyl estradiol (EE2), which is used worldwide in the treatment of some cancers and as a contraceptive, is often found in aquatic systems and is considered a pharmaceutically active compound (PhACs) in the environment. Current methods for the determination of this compound, such as chromatography, are expensive and lengthy and require large amounts of toxic organic solvents. In this work, a voltammetric procedure is developed and validated as a screening tool for detecting EE2 in water samples without prior extraction, clean-up, or derivatization steps. Application of the method we elaborate here to EE2 analysis is unprecedented. EE2 detection was carried out using differential pulse adsorptive cathodic stripping voltammetry (DP AdCSV) with a hanging mercury drop electrode (HMDE) in pH 7.0 Britton-Robinson buffer. The electrochemical process of EE2 reduction was investigated by cyclic voltammetry at different scan rates. Electroreduction of the hormone on a mercury electrode exhibited a peak at −1.16±0.02 V versus Ag/AgCl. The experimental parameters were as follows: −0.7 V accumulation potential, 150 s accumulation time, and 60 mV s−1scan rate. The limit of detection was 0.49 μg L−1for a preconcentration time of 150 s. Relative standard deviations were less than 13%. The method was applied to the detection of EE2 in water samples with recoveries ranging from 93.7 to 102.5%.

scholarly journals Perchlorate Levels in Polish Water Samples of Various Origin

Separations ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 37
Author(s):  
Przemysław Niziński ◽  
Patrycja Wiśniewska ◽  
Joanna Kończyk ◽  
Rajmund Michalski
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Limit Of Detection ◽  
Primary Objective ◽  
Swimming Pool ◽  
Limit Of Quantification ◽  
Reliable Determination ◽  
Pool Water ◽  
Drinking Waters ◽  
Swimming Pool Water

Perchlorate ion (ClO4−) is known as a potent endocrine disruptor and exposure to this compound can result in serious health issues. It has been found in drinking water, swimming pools, and surface water in many countries, however, its occurrence in the environment is still poorly understood. The information on perchlorate contamination of Polish waters is very limited. The primary objective of this study was to assess ClO4− content in bottled, tap, river, and swimming pool water samples from different regions of Poland and provide some data on the presence of perchlorate. We have examined samples of bottled, river, municipal, and swimming pool water using the IC–CD (ion chromatography–conductivity detection) method. Limit of detection and limit of quantification were 0.43 µg/L and 1.42 µg/L, respectively, and they were both above the current health advisory levels in drinking water. The concentration of perchlorate were found to be 3.12 µg/L in one river water sample and from 6.38 to 8.14 µg/L in swimming pool water samples. Importantly, the level of perchlorate was below the limit of detection (LOD) in all bottled water samples. The results have shown that the determined perchlorate contamination in Polish drinking waters seems to be small, nevertheless, further studies are required on surface and river samples. The inexpensive, fast, and sensitive IC–CD method used in this study allowed for a reliable determination of perchlorate in the analyzed samples. To the best of our knowledge, there are no other studies seeking to assess the perchlorate content in Polish waters.

scholarly journals Determination of cobalt in water samples by atomic absorption spectrometry after pre-concentration with a simple ionic liquid-based dispersive liquid-liquid micro-extraction methodology

2010 ◽  
Vol 8 (3) ◽  
pp. 617-625 ◽  
Author(s):  
Hossein Abdolmohammad-Zadeh ◽  
Elnaz Ebrahimzadeh
Keyword(s):  
Ionic Liquid ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Water Samples ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Experimental Conditions ◽  
Flame Atomic Absorption ◽  
Relative Standard

AbstractA rapid dispersive liquid-liquid micro-extraction (DLLME) methodology based on the application of 1-hexylpyridinium hexafluorophosphate [C6py][PF6] ionic liquid (IL) as an extractant solvent was applied for the pre-concentration of trace levels of cobalt prior to determination by flame atomic absorption spectrometry (FAAS). 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) was employed as a chelator forming a Co-PMBP complex to extract cobalt ions from aqueous solution into the fine droplets of [C6py][PF6]. Some effective factors that influence the micro-extraction efficiency include the pH, the PMBP concentration, the amount of ionic liquid, the ionic strength, the temperature and the centrifugation time which were investigated and optimized. In the optimum experimental conditions, the limit of detection (3s) and the enrichment factor were 0.70 µg L−1 and 60, respectively. The relative standard deviation (RSD) for six replicate determinations of 50 µg L−1 Co was 2.36%. The calibration graph using the pre-concentration system was linear at levels 2–166 µg L−1 with a correlation coefficient of 0.9982. The applicability of the proposed method was evaluated by the determination of trace amounts of cobalt in several water samples.

EXPERIMENTS ON THE RELATIVE SUSCEPTIBILITY OF WEEDS TO AUXIN HERBICIDES

1962 ◽  
Vol 40 (11) ◽  
pp. 1401-1409 ◽  
Author(s):  
J. R. Hay
Keyword(s):  
Phaseolus Vulgaris ◽  
Root Formation ◽  
Effective Control ◽  
Inorganic Salts ◽  
Dichlorophenoxyacetic Acid ◽  
Functional Importance ◽  
Molecular Configuration ◽  
Auxin Herbicides ◽  
Chlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid

Sections of stems of Silene cucubalus, Galeopsis tetrahit, and Phaseolus vulgaris were cultured under sterile conditions in media containing inorganic salts, sucrose, agar, and the herbicides 2-methyl, 4-chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, or 2-(2,4,5-trichlorophenoxy)propionic acid. The herbicide which gave the most effective control of a species under field conditions was also the most active in inducing root formation and proliferation on stem sections of that species. The response of the sections to these auxin herbicides diminished as the plants from which the sections were taken became more mature. The amount of herbicide recovered from treated shoots of these species was not correlated with susceptibility. It is postulated that susceptibility to these materials depends upon (i) the affinity of the species for the molecular configuration of the herbicide and (ii) the relative amount and functional importance of the susceptible tissues at the time of treatment.

scholarly journals Ionic Liquid-Multiwalled Carbon Nanotubes Nanocomposite Based All Solid State Ion-Selective Electrode for the Determination of Copper in Water Samples

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2869
Author(s):  
Cecylia Wardak ◽  
Karolina Pietrzak ◽  
Małgorzata Grabarczyk
Keyword(s):  
Carbon Nanotubes ◽  
Ionic Liquid ◽  
Solid State ◽  
Multiwalled Carbon Nanotubes ◽  
Water Samples ◽  
Limit Of Detection ◽  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Multiwalled Carbon ◽  
Copper Determination

A new copper sensitive all solid-state ion-selective electrode was prepared using multiwalled carbon nanotubes-ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) nanocomposite as an additional membrane component. The effect of nanocomposite content in the membrane on the electrode parameters was investigated. The study compares, among others, detection limits, sensitivity, and the linearity ranges of calibration curves. Content 6 wt.% was considered optimal for obtaining an electrode with a Nernstian response of 29.8 mV/decade. An electrode with an optimal nanocomposite content in the membrane showed a lower limit of detection, a wider linear range and pH range, as well as better selectivity and potential stability compared to the unmodified electrode. It was successfully applied for copper determination in real water samples.

scholarly journals Direct Detection of Toxic Contaminants in Minimally Processed Food Products Using Dendritic Surface-Enhanced Raman Scattering Substrates

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2726 ◽  
Author(s):  
Hannah Dies ◽  
Maria Siampani ◽  
Carlos Escobedo ◽  
Aristides Docoslis
Keyword(s):  
Raman Scattering ◽  
Limit Of Detection ◽  
Screening Method ◽  
Food Products ◽  
Surface Enhanced Raman Scattering ◽  
Liquid Food ◽  
Minimally Processed ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

We present a method for the surface-enhanced Raman scattering (SERS)-based detection of toxic contaminants in minimally processed liquid food products, through the use of a dendritic silver nanostructure, produced through electrokinetic assembly of nanoparticles from solution. The dendritic nanostructure is produced on the surface of a microelectrode chip, connected to an AC field with an imposed DC bias. We apply this chip for the detection of thiram, a toxic fruit pesticide, in apple juice, to a limit of detection of 115 ppb, with no sample preprocessing. We also apply the chip for the detection of melamine, a toxic contaminant/food additive, to a limit of detection of 1.5 ppm in milk and 105 ppb in infant formula. All the reported limits of detection are below the recommended safe limits in food products, rendering this technique useful as a screening method to identify liquid food with hazardous amounts of toxic contaminants.

Development of Rapid Colorimetric Assay for Detection of Gluconic Acid Using Iron(Ⅱ) and Indigo Carmine

2020 ◽  
Vol 42 (4) ◽  
pp. 525-525
Author(s):  
Yifeng Lan Yifeng Lan ◽  
Lixiang Zuo Lixiang Zuo ◽  
Yangyang Zhou Yangyang Zhou ◽  
Yanli Wei and Chuan Dong Yanli Wei and Chuan Dong
Keyword(s):  
Spectrophotometric Method ◽  
Gluconic Acid ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Low Cost ◽  
Indigo Carmine ◽  
Colorimetric Method ◽  
Food Samples ◽  
Reducing Agent ◽  
Acid Complex

In this work, a simple and rapid spectrophotometric method, which is based on the fact that Iron(Ⅱ) -gluconic acid complex as a kind of reducing agent deterioration of indigo carmine dyes, was developed to detect gluconic acid in food. Under the optimal experimental condition, a linear range of 3.6 M to 900 M was obtained for gluconic acid with a limit of detection of 1.1 μM. The colorimetric method was rapid and robust with a low cost and can be applied to gluconic acid detection in food samples.

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