Simple flow injection colorimetric system for determination of paraquat in natural water

Chuntib, Prakit; Jakmunee, Jaroon

doi:10.1016/j.talanta.2015.06.066

Cited by 29 publications

(9 citation statements)

References 26 publications

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“…25 Maximum permissible levels for paraquat residues in drinking water vary in different countries from 40 to 400 nM. 26 Standard methods of paraquat determination include gas chromatography mass spectrometry (GC/MS), 27 radioimmunoassay, 28 fluorescent probe titration, 29 spectrophotometry, 30 and more recently flow injection colorimetric assay 31 or surfaceenhanced Raman spectroscopy. 32 Some of these methods have certain disadvantages as they require bulky instrumentation and Figure 1.…”

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confidence: 99%

Mesoporous Silica Thin Films for Improved Electrochemical Detection of Paraquat

et al. 2018

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An electrochemical method was developed for rapid and sensitive detection of the herbicide paraquat in aqueous samples using mesoporous silica thin film modified glassy carbon electrodes (GCE). Vertically aligned mesoporous silica thin films were deposited onto GCE by electrochemically assisted self-assembly (EASA). Cyclic voltammetry revealed effective response to the cationic analyte (while rejecting anions) thanks to the charge selectivity exhibited by the negatively charged mesoporous channels. Square wave voltametry (SWV) was then used to detect paraquat via its one electron reduction process. Influence of various experimental parameters (i.e., pH, electrolyte concentration, and nature of electrolyte anions) on sensitivity was investigated and discussed with respect to the mesopore characteristics and accumulation efficiency, pointing out the key role of charge distribution in such confined spaces on these processes. Calibration plots for paraquat concentration ranging from 10 nM to 10 μM were constructed at mesoporous silica modified GCE which were linear with increasing paraquat concentration, showing dramatically enhanced sensitivity (almost 30 times) as compared to nonmodified electrodes. Finally, real samples from Meuse River (France) spiked with paraquat, without any pretreatment (except filtration), were analyzed by SWV, revealing the possible detection of paraquat at very low concentration (10-50 nM). Limit of detection (LOD) calculated from real sample analysis was found to be 12 nM, which is well below the permissible limits of paraquat in drinking water (40-400 nM) in various countries.

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confidence: 99%

Mesoporous Silica Thin Films for Improved Electrochemical Detection of Paraquat

et al. 2018

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“…Therefore, a reagent must be stabilized when applying the present device to the on-site analysis of paraquat. Many publications have reported that sodium dithionite is stable for only a few hours following exposure to moisture and O 2 [10,17] that oxidizes sodium dithionite to hydrogen sulfite and hydrogen sulfate [28], as shown in Eq. (1).…”

Section: Stability Of Sodium Dithionite Solution 331 Effect Of Aciditymentioning

confidence: 99%

“…Buah-Bassuah et al used an LED with a 365 nm emission in fluorometry to study the chlorophyll content in the leaves of fruit [16]. Chuntib and Jakmunee utilized a red LED as a light source coupled with a flow system for paraquat determination in environmental water [17], but the system consisted of pumps, a PC, and a detector that diminished its portability. De Lima constructed a portable photometer unit using two IR-LEDs (1,300 nm and 1,689 nm) as light sources that could be used to investigate aromatic hydrocarbons in water [18].…”

Section: Introductionmentioning

confidence: 99%

On-site analysis of paraquat using a completely portable photometric detector operated with small, rechargeable batteries

Seetasang

Kaneta

2020

Analytica Chimica Acta

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This work describes a methodology that can be used to achieve on-site analysis of paraquat in water samples by using a miniaturized portable photometer consisting of a couple of light-emitting diodes (LEDs).Paraquat produces a colored radical via a redox reaction with sodium dithionite, which is unstable against oxygen in solution. The steps taken to stabilize the reagent solution included control of the pH and the addition of organic solvents, but the most effective was the formation of an oil layer. Together, these steps stabilized the reagent solution for two days. An increase in the duration of reagent stability, however, is necessary in order to transport the reagent for on-site applications in remote locales. For the time being, an excess amount of solid sodium dithionite can be added directly to sample solutions because the unreacted dithionite shows no influence on absorbance of the paraquat radical. Orange LEDs with a maximum emission wavelength of 609 nm were employed in the portable photometer to measure the absorbance of paraquat radical produced by a redox reaction that has an absorption maximum of 603 nm. The developed photometer showed excellent performance with a linear range of from 2.0 mg L -1 to 40.0 mg L -1 and a linear regression (r 2 = 1). The limits of detection and quantification were 0.5 mg L -1 and 1.5 mg L -1 , respectively, intra-day precision (n=3) and inter-day precision (n=5) were both less than 5%, and accuracy based on the percentage of sample recovery ranged from 89±0 to 105±0% (n=3). The proposed method was applied to the analysis of paraquat in water samples taken from rice fields. The results showed no paraquat in all thirteen samples, which could have been due to strong adsorption of paraquat by soil particles and/or to complications with the sampling conditions. To confirm the adsorption onto soil of paraquat contained in water, we constructed an artificial rice field where water containing paraquat was impounded above the soil layer. The results showed that paraquat in water gradually decreased within three days and could be measured in the soil on the fourth day. These results were confirmed by HPLC analysis, which underscores the utility of this portable photometer for the on-site monitoring of paraquat in water samples.

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“…Although paraquat can be photochemically decomposed by ultraviolet (UV) radiation and be degraded by microorganisms, such processes are relatively slow thus may not be practical [3]. Paraquat is highly water-soluble but low volatile [4]. Therefore, paraquat can escalate environmental contamination risks, especially in aquatic environments, such as agricultural runoff and industrial wastewater discharges [5].…”

Section: Introductionmentioning

confidence: 99%

“…Many analytical methods have been developed for evaluating paraquat levels in ecosystems. Such analyses include ow injection analysis [4], liquid chromatography-mass spectrometry (LC-MS) [7], highperformance liquid chromatography (HPLC) [8], electrochemical analysis [9], and uorescence-probe detecting analysis [10]. These methods have generally provided excellent LOD and selectivity for paraquat detection.…”

Section: Introductionmentioning

confidence: 99%

Smartphone-Based Paper Microfluidic Detection of Paraquat Mediated by Citrate-Capped Silver Nanoparticles

Sritong

Kongpreecha

Yoon

et al. 2021

Preprint

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Paraquat has been widely used in agriculture due to its efficient herbicidal activity. However, its remaining residues in the environment have caused eco-toxicity to live organisms and humans. Therefore, a portable and sensitive sensing system is required for field-monitoring paraquat towards eco-friendly usage. Toward this goal, citrate-capped silver nanoparticles (AgNPs) on a microfluidic paper analytic device (µPAD) were used to detect paraquat, accompanied by smartphone detection. Capillary action through paper fibers enabled the distribution of pre-loaded AgNPs across paper microfluidic channels and allowed rapid citrate-paraquat binding, which led to rapid, reproducible, and sensitive detection of paraquat. Full extents of color changes were recorded within 1 min using a smartphone camera, using only 2 µL samples. The assay's linear range was from 2.5 to 20 ppm, and the limit of detection was 2.3 ppm (8.94 µM) paraquat. Successful selectivity was also demonstrated using several different ions and herbicides, without substantial non-specific aggregation. Moreover, paraquat was further assayed with co-existing ions and field water samples, with satisfactory analytical recoveries of 95−117%, demonstrating its potential application towards on-site and field-ready assay of paraquat.

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Simple flow injection colorimetric system for determination of paraquat in natural water

Cited by 29 publications

References 26 publications

Mesoporous Silica Thin Films for Improved Electrochemical Detection of Paraquat

Mesoporous Silica Thin Films for Improved Electrochemical Detection of Paraquat

On-site analysis of paraquat using a completely portable photometric detector operated with small, rechargeable batteries

Smartphone-Based Paper Microfluidic Detection of Paraquat Mediated by Citrate-Capped Silver Nanoparticles

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