RESUMO
Copper ferrite-copper oxide (CuO-CuFe2O4) nanoparticles as a semiconductor composite with p-n junction were synthesized by co-precipitation reaction. Then, a novel CuO-CuFe2O4 carbon paste modified electrode was fabricated which displays an effectual electrocatalytic response to the oxidation of acetaminophen (AC) and codeine (CO). A linear range of 0.01-1.5 µmol L-1 and 0.06-10.0 µmol L-1 with the detection limits of 0.007 µmol L-1 and 0.01 µmol L-1 were achieved for AC and CO, respectively. The practical usage of the proposed sensor revealed reasonable results for quantification of AC and CO in biological fluids.
Assuntos
Acetaminofen/sangue , Acetaminofen/urina , Codeína/sangue , Codeína/urina , Técnicas Eletroquímicas/métodos , Catálise , Cobre/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Compostos Férricos/química , Humanos , Limite de Detecção , Nanopartículas/química , OxirreduçãoRESUMO
A noble glassy carbon electrode modified with Au nanoparticles and 2-amino-4-(3,4-dihydroxyphenyl)-6-(hydroxymethyl)-8-oxo-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile, was fabricated for electrocatalytic determination of hydrazine (AuNPs/APP/GCE). Large over-potential and interference of some species are two limitation factors for the determination of hydrazine at bare electrode. This modified electrode is able to shift a signal to the negative potential, and can amplify the oxidation current of hydrazine by 28.0 time, compared to bare electrode. The diffusion coefficient, D, and the heterogeneous rate constant, kh, for the oxidation of hydrazine at the modified surface were calculated by chronoamperometric studies. Finally, the fabricated sensor was agreeably utilized for the determination of hydrazine in real samples.
Assuntos
Técnicas Eletroquímicas/métodos , Hidrazinas/química , Nitrilas/química , Eletrodos , OxirreduçãoRESUMO
Analytical performance of conventional spectrophotometer was developed by coupling of effective dispersive liquid-liquid micro-extraction method with spectrophotometric determination for ultra-trace determination of cobalt. The method was based on the formation of Co(II)-alpha-benzoin oxime complex and its extraction using a dispersive liquid-liquid micro-extraction technique. During the present work, several important variables such as pH, ligand concentration, amount and type of dispersive, and extracting solvent were optimized. It was found that the crucial factor for the Co(II)-alpha benzoin oxime complex formation is the pH of the alkaline alcoholic medium. Under the optimized condition, the calibration graph was linear in the ranges of 1.0-110 µg L(-1) with the detection limit (S/N = 3) of 0.5 µg L(-1). The preconcentration operation of 25 mL of sample gave enhancement factor of 75. The proposed method was applied for determination of Co(II) in soil samples.