Flow Injection Analysis of Maleic Hydrazide Using an Electrochemical Sensor Based on Palladium‐Dispersed Carbon Paste Electrode

Abstract

A new analytical methodology for the electrochemical detection of the herbicide maleic hydrazide (3,6-dihydroxypyridazine) by flow injection analysis is presented. This method is supported by the novel application of a palladium-dispersed carbon paste electrode as an amperometric sensor for this herbicide. Maleic hydrazide shows anodic electrochemical activity on carbon-based electrodes (glassy carbon or carbon paste electrodes) in all the pH range. This electrochemical activity is enhanced using metal-dispersed carbon paste electrodes, especially at Pddispersed CPE which displays good oxidation signals at 690 mV (0.050 M phosphate buffer pH 7.0), 140 mV lower than at unmodified electrodes. Under the optimized conditions, the electroanalytical performance of Pd-dispersed CPE in flow injection analysis was excellent, with good reproducibility (RSD 3.3%) and a wide linear range (1.9 Â 10 À7 to 1.0 Â 10 À4 mol L À1 ). A detection limit of 1.4 Â 10 À8 mol L À1 (0.14 ng maleic hydrazide) was obtained for a sample loop of 100 mL at a fixed potential of 700 mV in 0.050 M phosphate buffer solution at pH 7.0 and a flow rate of 2.0 mL min À1. The proposed method was applied for the maleic hydrazide detection in natural drinking water samples.

Voltammetric determination of phytoinhibitor maleic hydrazide using PEDOT:PSS composite electrode

“…The sensors reported in the literature [16][17][18][19] due to wider linear range, lower limit of detection and higher sensitivity. This is mainly because that the prepared electrode combined excellent performance of different components.…”

“…Zapardiel et al [18] detected MH via electrochemical oxidation, they pointed out that the overall electrochemical oxidation process was ascribed to deprotonation pathways and could be related to the pK a value of MH. Varmaghani and Nematollahi studied electrochemical oxidation and reduction of MH (quinoid structure) in protic and aprotic solvents [50].…”

“…Compared with aforementioned traditional techniques, electrochemical technique is a powerful tool owing to its advantages of simple operation, cost effectiveness, fast analysis, high sensitivity, and real-time online detection. Unfortunately, only few studies have been reported for MH determination 4 using chemo/bio-sensing technology [16][17][18][19]. Shibata and Zuman reported the detection of MH by polarographic method [16].…”

“…presented a new analytical methodology for the amperometric detection of MH by flow injection analysis, and this method was applied for MH detection in natural drinking water samples [18]. More recently, Fang et al developed a flow injection chemiluminescence sensor for MH determination using molecularly imprinted polymer as recognition element, and the proposed sensor was used for MH detection in vegetable samples [19].…”

Determination of maleic hydrazide residues in garlic bulbs by HPLC

“…For determination of MH, the HPLC chromatographic conditions were: 4.5 m, 100 Å C18 column (150 mm × 4.6 mm; Shimadzu, Kyoto, Japan) with a mobile phase of deionized water: methanol, 97:3 (v:v) at 1 mL min −1 , column temperature: 25 • C, and injection volume: 20 L. UV detection was at 303 nm [10,23,26,33,34]. Under these conditions the MH was quantified in 12.5 min.…”