Kinetic Enzymatic Determination of Chlorpyriphos in Apples

Dı́az, A. Navas; Sánchez, Francisco; Río, V. Bracho del

doi:10.1080/00032719508002679

Cited by 8 publications

(6 citation statements)

References 8 publications

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“…In this work, we evaluated the wavelength where the fluorescence of the hydrolyzed indoxyl acetate occurred. As can be seen in Figure 9 A, it was 404 and 475 nm, which corresponded with already-published works [ 4 , 41 ]. However, we found that the signals in the area of 480 nm did not have optimal behavior for kinetic measurements, because they were not stable.…”

Section: Resultssupporting

confidence: 89%

“…This indicates that using slope values will not be very accurate when measuring samples with low cholinesterase activity. The results of the end-point fluorimetry are comparable to those of the stand-alone fluorimetry conducted by Navas Díaz et al, who determined the limit of detection for indoxyl acetate to be 13.8 µmol/L [41]. The measuring conditions were very similar in the first 100 s of the reaction to the first 120 s in our work.…”

Section: Simple Fluorimetric Approachsupporting

confidence: 89%

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Open Meter Duo: Low-Cost Instrument for Fluorimetric Determination of Cholinesterase Activity

Keresteš,

Mozo,

Pohanka

2024

Sensors

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Environmental screening is essential due to the increased occurrence of harmful substances in the environment. Open Meter Duo (OMD) is an open-source field photo/fluorimeter that uses an RGB diode that imitates a color according to the selected wavelength and uses a UV LED from the security kit diode as an excitation light source. The prepared PCB shield with a 3D-printed aperture was connected to Arduino UNO R4 WiFi. This system was used for the fluorescent detection of cholinesterase activity with the indoxyl acetate method. Carbofuran—a toxic pesticide—and donepezil—a drug used to treat Alzheimer’s disease—were tested as model inhibitors of cholinesterase activity. The limit of detection of indoxyl acetate was 11.6 μM, and the IC50 values of the inhibitors were evaluated. This system is optimized for wireless use in field analysis with added cloud support and power source. The time of analysis was 5 min for the fluorimetric assay and 20 min for the optional photometric assay. The time of field operation was approximately 4 h of continuous measurement. This system is ready to be used as a cheap and easy control platform for portable use in drug control and point-of-care testing.

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Section: Resultssupporting

confidence: 89%

Section: Simple Fluorimetric Approachsupporting

confidence: 89%

Open Meter Duo: Low-Cost Instrument for Fluorimetric Determination of Cholinesterase Activity

Keresteš,

Mozo,

Pohanka

2024

Sensors

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“…Spectrophotometric, GC, HPLC and polarographic techniques have been used for determination of a number of organophosphorus pesticides [1][2][3][4][5][6]. Spectrophotometric and enzymatic methods have been used for determination of chlorpyrifos in apples [7]. Also, first derivative and kinetic spectrophotometric methods were applied for determination of chlorpyrifos and some other organophosphorus pesticides [8].…”

Section: Introductionmentioning

confidence: 99%

Differential Pulse Polarographic Analysis of Chlorpyrifos Insecticide

1998

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The differential pulse polarographic (DPP) behavior of chlorpyrifos (CP) was investigated over a wide range of pH (pH 1.8-pH 10.1). CP compound displays a well-resolved cathodic reduction peak at ¹1.2 V (vs. Ag/AgCl) (pH 3.2). This peak probably corresponds to the reduction of the --C=N-centre of the pyridyl moiety. The effect of solution and operational parameters on the sensitivity of the DPP peak was carefully examined in order to select the optimum conditions for determination of the CP compound. Under the optimum conditions the reduction response gives a linear calibration plot over a concentration range of 9.70 × 10 ¹7 -6.92 × 10 ¹6 M and the detection limit was found to be 8.7 × 10 ¹7 M. The effects of some diverse metal ions, anions and some other organophosphorus insecticides on the determination of CP compound were studied. The applicability of DPP for determination of the CP insecticide in a commercial sample as well as in some irrigation water (treated waste water and underground water) was detected.

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“…Several analytical methods, including gas (Hladká and Nosá l, 1967;Alvarez et al, 2008) and liquid chromatography (Itoh et al, 1996;Franko et al, 2005;Sanchez-Ortega et al, 2005), immunoassays (Cho et al, 2004;Kim et al, 2007;Zhang et al, 2008), fluorescence and chemiluminescence spectroscopy (Diaz et al, 1995;Garcia Sanchez et al, 2003;Zhu et al, 2006;Dasary et al, 2008), electrochemical techniques (Navas Diaz and Gonzalez-Garcia, 1994;Fernandez-Sanchez and Costa-García, 1998;Gehring et al, 1999;Pemberton et al, 1999), and biosensors based on cholinesterase or alkaline phosphatase (ALP) inhibition (Garcia Sanchez et al, 2003;Kumaran and Morita, 1995;Navas Diaz and Ramos Peinado, 1997) have been used for the determination of organophosphorus pesticides (OP). More recently, electrochemical detection of FT and other OP pesticides has been described (Cai et al, 2014;Geremedhin et al, 2013).…”

Section: Introductionmentioning

confidence: 98%