Automated high-performance liquid chromatographic method for the determination of organophosphorus pesticides in waters with dual electrochemical (reductive—oxidative) detection

Capillary Electrophoresis Microchips for Separation and Detection of Organophosphate Nerve Agents

“…Using a MES buffer (20 mM, pH 5.0) as running buffer and a separation voltage of 2000 V, the four peaks are well resolved, with the entire assay requiring ∼2.5 min. Significantly longer separations (∼20 min) were reported for analogous conventional liquid chromatographic assays that display a similar elution order . A relatively flat baseline and a low noise level are observed, despite the negative detection potential (−0.5 V), use of nondearated running buffer, the high-separation voltage, and the absence of a decoupling mechanism.…”

“…The high speed and sensitivity of the MEKC/EC microchip system are consistent with various on-site environmental and security needs. Lower detection limits are expected in connection with a dual electrochemical detection, i.e., via anodic measurements of the reduction product in a series (upstream−downstream) configuration 1 Separation and detection of organophosphate nerve agent compounds: (a) 1.0 × 10 -5 M paraoxon, (b) 1.0 × 10 -5 M methyl parathion, (c) 2.0 × 10 -5 M fenitrothion, and (d) 4.0 × 10 -5 M ethyl parathion.…”

“…Miniaturized analytical systems (referred to as “lab-on-a-chip” devices) are attracting considerable interest − due to the potential for greatly enhancing the speed of analytical separations, while dramatically reducing the system size or weight and the consumption of samples and reagents. Separation of OP compounds, particularly OP pesticides, has traditionally been carried out using conventional liquid or micellar chromatographic systems, in connection with electrochemical or optical (UV) detection. An analogous on-chip separation/detection microsystem that can meet the requirements of on-site environmental monitoring or rapid field detection of chemical warfare agents has not been reported.…”

Electrochemical Sensor for Organophosphate Pesticides and Nerve Agents Using Zirconia Nanoparticles as Selective Sorbents

“…To avoid the use of enzymes and antibodies, molecular imprint technologies with high selectivity toward specific OP species have been developed and applied to the detection of pesticides in environmental samples. , Nitroaromatic OPs, such as paraoxon, methyl parathion, and fenitrothion (Figure ), exhibit good redox activities at the electrode surface . Electrochemical detection of nitroaromatic OPs showed great promise when it was coupled with different separation technologies, such as high-performance liquid chromatography or capillary electrophoresis . Surprisingly, little attention has been given to direct electrochemical sensing of nitroaromatic OP compounds, despite their inherent redox activity and the compact nature of electrochemical instruments.…”

Application of a 32-Microband Electrode Array Detection System for Liquid Chromatography Analysis

“…Electrochemical detection is one of the most versatile and sensitive detection methods used in liquid chromatography. − Among the various electrochemical techniques applied, amperometric determination, due to the inherent high selectivity and low detection limit, is the most frequently used method. − Besides the conventional single- and dual-electrode detectors used, − versatility of electrochemical determination has been improved by the development of multielectrode detectors. Electrode arrays consisting of 4, − 8, , 11, and 16 − electrodes having various flowing patterns have been proposed.…”