Voltammetric method for sensitive determination of herbicide picloram in environmental and biological samples using boron-doped diamond film electrode

A self-assembled sensor based on a boron-doped diamond was investigated as a sensitive tool for voltammetric analysis of a member of a pyridine herbicide family - picloram. A cyclic voltammetry and a differential pulse voltammetry were applied for investigation of the voltammetric behaviour and quantification of this herbicide. Picloram yielded one well-developed irreversible oxidation signal at a very positive potential about +1.5 V vs. Ag/AgCl/3 mol L−1 KCl electrode in an acidic medium and 1 mol L−1 H2SO4 was chosen as a suitable supporting electrolyte. Operating parameters of differential pulse voltammetry were optimized and the proposed voltammetric method provided a high repeatability (a relative standard deviation of 20 repeated measurements at a concentration level of picloram of 50 µmol L−1 equaled to 2.58%), a linear concentration range from 2.5 to 90.9 µmol L−1 and a low limit of detection (LD = 1.64 µmol L−1). Practical usefulness of the ‘environmentally-green’ electrochemical sensor was verif...

Self-assembled sensor based on boron-doped diamond and its application in voltammetric analysis of picloram

This study describes the utilisation of a glassy carbon electrode modified with a composite of multi-walled carbon nanotube and Cr-based metal-organic framework (MIL-101, Cr-BDC, BDC = 1,4-benzenedicarboxylate) for the sensitive, simple and fast voltammetric determination of picloram in environmental samples. Under optimum conditions, additions of picloram using square wave voltammetry showed linear ranges of picloram concentrations from 24.15 to 3018 µg∙L‒1 (0.1–12.5 μM) and from 3018 to 9658 µg∙L‒1 (12.5–40 μM) with a detection limit of 14.49 µg∙L‒1 (0.06 µM). The method was successfully applied to the determination of picloram in tap and river water samples spiked with picloram without any purification step by the standard addition method. The good recovery values obtained ranging from 97.5% to 105.0% revealed the reliability and accuracy of the method.

Sensitive electrochemical detection of picloram utilising a multi-walled carbon nanotube/Cr-based metal-organic framework composite-modified glassy carbon electrode

Temperature-enabled reversible "On/Off" switch-like hazardous herbicide picloram voltammetric sensor in agricultural and environmental samples based on thermo-responsive PVCL-tethered MWCNT@Au catalyst.

A silver solid amalgam electrode was employed for the first time for the determination of the pyridine herbicide picloram. The voltammetric behavior of this herbicide was studied using cyclic, direct current, and differential pulse voltammetry on the mercury meniscus modified silver solid amalgam electrode. All results were compared with those achieved on the classic hanging mercury drop electrode. One reduction signal, which was suitable for analytical purposes, was recorded on the amalgam electrode after addition of picloram. The current response of the herbicide increased linearly in the concentration range from 1 × 10−7 to 8 × 10−5 moles per liter, and a limit of detection of 8.78 × 10−8 moles per liter was obtained using differential pulse voltammetry under the optimized conditions. The selectivity and applicability of the voltammetric technique was verified by an interference study and analysis of fortified environmental samples with excellent recoveries: 100.0%(tap water), 100.5% (dam water...

Voltammetric Analysis of Herbicide Picloram on the Silver Solid Amalgam Electrode

The herbicide picloram, 4-amino-3,5,6-trichloro-picolinic acid, can be determined at 0.02 ppm, without concentration, by pulse polarography. The effects of pH, ionic strength, and buffer constituents on the catalytic hydrogen process have been studied to optimize conditions for highest sensitivity for picloram. A buffer solution 0.01 M sodium acetate-0.026M acetic acid was used to evaluate the analysis of a natural water system. Errors range from 3–8 % (relative) in the 0.05–0.20 ppm picloram range with precisions of ± 5% (relative) or better. Interferences with 0.1 ppm picloram from 100 ppm Cr(VI) and Zn(II) are severe; neither ion interferes at 1 ppm. Fe(III) interference can be eliminated by masking with EDTA. Mn(II), Cu(II), and Pb(TI) do not interfere at 10 ppm.

J. M. Mann

Papers

Herbicide Analysis by Pulse Polarography-Picloram