Ultra-sensitive electrochemical sensing of acetaminophen and codeine in biological fluids using CuO/CuFe2O4 nanoparticles as a novel electrocatalyst.

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.

Sensitive spectrophotometric determination of Co(II) using dispersive liquid-liquid micro-extraction method in soil samples.

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.

A chemiluminescent metalloimmunoassay based on copper-enhanced gold nanoparticles for quantification of human growth hormone.

A chemiluminescence (CL) immunoassay was developed to determine human growth hormone (hGH) based on copper-enhanced gold nanoparticles. In this method, gold nanoparticles were deposited on polystyrene wells for adsorption of human growth antibodies as well as catalyst for reducing of copper ions from the copper enhancer solution. The reduction of copper ions was prevented where the gold nanoparticles were covered by the antibody-antigen immunocomplex. The deposited copper on Au nanoparticles was then dissolved in HNO3 solution and quantified using the CL method. The CL intensity response was logarithmically dependent on the hGH concentrations over the range 0.2-50 ng/mL, with a detection limit (3σ) of 0.036 ng/mL.