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Herein, the fabrication and electrochemical characterization of a novel clorsulon (CLO) sensor were evaluated. Among the different tested metal oxides nanostructures, bulk modification of the carbon paste working electrode with zinc oxide exhibited the proper electrocatalytic activity towards CLO with irreversible anodic oxidation peak at 1.02 in universal buffer pH 7.0. Clorsulon molecule showed diffusion–reaction mechanism through the involvement of one-electron and one proton as illustrated by the sweep rate, pH studies, and sustained by the molecular orbital calculations. The fabricated sensors showed linear calibration curves within the CLO concentration range from 0.45 to 10.13 × 10−9 mol L−1 with LOD value of 0.14 × 10−9 mol L−1. Enhanced sensitivity with good measurement reproducibility and long operational lifetime were cited as shining futures of the fabricated sensor. The constructed sensors were utilized for clorsulon quantification in veterinary formulations and milk samples with high accuracy and precision compared with the traditional methods.

Ethopabate is a veterinary drug used in the prophylaxis and treatment of coccidiosis in chickens. The presence of drug residues in edible tissues can be dangerous to human consumers. It may cause direct toxic effects, allergic reactions and increased bacterial resistance. A highly sensitive, simple and rapid spectrofluorimetric method was developed for the determination of ethopabate in its veterinary formulations. The proposed method is based on measuring the native fluorescence of ethopabate in water at 364 nm after excitation at 270 nm. The fluorescence-concentration plot was rectilinear over the range of 2-100 ng/mL, with a limit of detection of 2.9 ng/g and a limit of quantification of 9.8 ng/g for ethopabate. The method was successfully applied to the analysis of ethopabate in its commercial veterinary formulations and the results were in good agreement with those obtained with the reference method. The method was extended to the determination of ethopabate residues in chicken muscles and liver, and the results were satisfactory. The recoveries obtained were in the 108.36-113.42% range. No organic solvents are used in the procedure, so it can be considered a type of 'green' chemistry. [ABSTRACT FROM AUTHOR]

[Display omitted] • First report on spectrofluorimetric determination of nitroxynil in its pure form and VET formulations. • Determination of fluorescence quantum yield of nitroxynil using single-point method. • Detection of nitroxynil residues in bovine meat, liver, kidney and milk samples. Because of the frequent treatment of dairy cows with nitroxynil (NTX), the presence of the later residues in animal tissues and milk has a significant concern. The quantum yield of the reaction product was calculated. A highly sensitive and rapid spectrofluorometric method for determining the anthelmintic drug (NTX) residual amounts is developed. The proposed approach is based on using Zn/HCl to reduce NTX nitro group to an amino group, resulting in a highly fluorescent derivative that was detected at each of λ em 302 nm and 364 nm after excitation at λ ex = 277 nm. The experimental conditions were carefully studied and optimized. The proposed approach showed good linearity (r2 ≥ 0.9998) with linearity range of 10.0–100.0 ng/mL with a detection limit of 1.89 ng/mL, 1.27 ng/mL and quantification limit of 5.73 ng/mL, 3.86 ng/mL at λ em 302 nm and 364 nm, respectively; that is far below the Minimum Regulatory Limits (MRLs) of NTX in animal tissues and milk. The proposed approach was successfully applied for the analysis of the drug in its veterinary formulations, and the obtained results agreed well with those of the official British Pharmacopeia method. Moreover, the proposed method's application was extended to efficiently determine the residues of nitroxynil in meat, liver, kidney and milk samples. [ABSTRACT FROM AUTHOR]

Herein, the fabrication and electrochemical characterization of a novel clorsulon (CLO) sensor were evaluated. Among the different tested metal oxides nanostructures, bulk modification of the carbon paste working electrode with zinc oxide exhibited the proper electrocatalytic activity towards CLO with irreversible anodic oxidation peak at 1.02 in universal buffer pH 7.0. Clorsulon molecule showed diffusion–reaction mechanism through the involvement of one-electron and one proton as illustrated by the sweep rate, pH studies, and sustained by the molecular orbital calculations. The fabricated sensors showed linear calibration curves within the CLO concentration range from 0.45 to 10.13 × 10−9 mol L−1 with LOD value of 0.14 × 10−9 mol L−1. Enhanced sensitivity with good measurement reproducibility and long operational lifetime were cited as shining futures of the fabricated sensor. The constructed sensors were utilized for clorsulon quantification in veterinary formulations and milk samples with high accuracy and precision compared with the traditional methods. [ABSTRACT FROM AUTHOR]

Ethopabate is a veterinary drug used in the prophylaxis and treatment of coccidiosis in chickens. The presence of drug residues in edible tissues can be dangerous to human consumers. It may cause direct toxic effects, allergic reactions and increased bacterial resistance. A highly sensitive, simple and rapid spectrofluorimetric method was developed for the determination of ethopabate in its veterinary formulations. The proposed method is based on measuring the native fluorescence of ethopabate in water at 364 nm after excitation at 270 nm. The fluorescence-concentration plot was rectilinear over the range of 2-100 ng/mL, with a limit of detection of 2.9 ng/g and a limit of quantification of 9.8 ng/g for ethopabate. The method was successfully applied to the analysis of ethopabate in its commercial veterinary formulations and the results were in good agreement with those obtained with the reference method. The method was extended to the determination of ethopabate residues in chicken muscles and liver, and the results were satisfactory. The recoveries obtained were in the 108.36-113.42% range. No organic solvents are used in the procedure, so it can be considered a type of 'green' chemistry., (Copyright © 2014 John Wiley & Sons, Ltd.)