Determination of Metribuzin with a Cobalt Phthalocyanine-Modified Carbon Paste Electrode

Abstract

Metribuzin is a widely used pesticide with a half-life of up to 2 months and high affinity to organic matter that should be carefully monitored. Here is reported the development of a modified carbon paste electrode using cobalt phthalocyanine as a biomimetic catalyst for the determination of metribuzin. The diffusion coefficient of metribuzin at room temperature was (59 � 16) � 10 −6 cm 2 s −1 and the apparent Michaelis-Menten constant (K ap M) was (7.4 � 0.6) � 10 −6 mol L −1. Electroanalytical measurements were performed by amperometry and the following figures of merit were obtained: limit of detection of 5.3 � 10 −6 mol L −1 (1.14 mg L −1), linear range up to 2.0 � 10 −4 mol L −1 , recoveries above 93% (performed on spiked water samples), interday repeatability of 4.5% and intraday repeatability of 3.5%, and suitable selectivity.

Penta-coordinated transition metal macrocycles as electrocatalysts for the oxygen reduction reaction

“…These structures are macrocycles with metal centers like iron [22][23][24][25][26][27][28], cobalt [29][30][31][32], copper [33][34][35], and nickel [33,34,36] bearing 4 pyrrolic nitrogen atoms. Porphyrins and phthalocyanines have been used as electrodes and have been reported for a wide range of reactions such as the ORR [32,[37][38][39][40], reduction of CO 2 [41][42][43][44][45], and the oxidation of H 2 O 2 and hydrazine [46,47] organic [48][49][50][51][52], biological [53,54] and inorganic compounds [55][56][57][58][59][60][61][62], as well as other forms of bio-mimicking [63,64]. They are also interesting since they may be readily bound to the surface of electrode materials such as carbon nanomaterials …”

S(O)MWCNT/modified Carbon Paste – A Non‐enzymatic Amperometric Sensor for Direct Determination of 6‐Mercaptopurine in Biological Fluids

“…As illustrated in Figure 3(b) linear dependency between peak current and v can be concluded by the regression equation of Ipa(μA) = 0.6179 + 0.9760 v (R 2 = 0.9993). These results suggest that the electrode process was only by adsorption controlled process over the entire v range [47][48][49][50][51]. Further investigations indicated that logarithm of anodic peak current of analyte was linearly proportional to logarithm of scan rate.…”