15 research outputs found
A new method for the extraction of fetal ECG from the dependent abdominal signals using blind source separation and adaptive noise cancellation techniques
Highly sensitive and selective detection of 4-nitroaniline in water by a novel fluorescent sensor based on molecularly imprinted poly(ionic liquid)
Electrochemical behavior study of salicylic acid following azo dye formation with 2,4-dinitrophenylhydrazine: Analytical evaluation
A new simple, accurate and cost-effective chronoamperometry (CA) - based approach coupled with azo coupling reaction has been put forward for quantitative analysis of salicylic acid. The reaction involves a two-step process of oxidation of the 2,4-dinitrophenylhydrazine (DNPH) by potassium iodate to give a 2,4-dinitrophenylhydrazinium cation at 0–5 °C and coupling with salicylic acid (SA) to form red salicylic acid-derived azo dye. Electrochemical impedance spectroscopy, square wave voltammetry and chronoamperometry methods were used to characterize the electrochemical behavior of the salicylic acid-derived azo dye. Studies on different variables affecting the reaction were optimized. Under the optimal conditions, amperometric studies showed that the current response exhibits a wide linearity range from 0.1 to 0.0005 mmol L−1 for SA and the limit of detection and quantification are found to be 0.0001 and 0.0015 mmol L−1 (S/N = 3 & 10) respectively. Therefore, the developed method was successfully applied for routine determination of SA in pharmaceutical samples. Keywords: salicylic acid, Azo coupling, DNPH, Chronoamperometr
Electrochemical impedance spectroscopy measurements for determination of derivatized aldehydes in several matrices
A simple, selective and sensitive electrochemical method is described for the determination of different aldehydes at glassy carbon electrode using electrochemical impedance spectroscopy (EIS). The measurements were performed after their derivatization with 2,4-dinitrophenylhydrazine (DNPH) in acidic medium. The impedance measurements were investigated in the frequency range from 100 mHz to 100 kHz at a potential of 1.0 V versus Ag/AgCl. The Nyquist plots were modeled with a Randle’s equivalent circuit. The charge transfer resistance was identified as the dependent parameter on relevant concentration of aldehydes (determined as their hydrazones). Under the optimized conditions, the linearity was established over the concentration range of 1000–0.05 μmol L−1. The limits of detection (LODs) obtained were from 0.097 to 0.0109 μmol L−1. Finally, the developed method has been applied to the determination of aldehydes in drinking water, orange juice and apple vinegar samples with relative standard deviations (RSDs) < 3.1% and acceptable recovery rate (around of 80%)
Correlation between catalysis properties of activated carbon and nature/position of substitution in the aromatic ring of phenol
Catalytic effect of silver particles supported on chitosan surface for the electrochemical sensing para
Green synthesis of silver nanoparticles using Phoenix dactylifera seed extract and their electrochemical activity in Ornidazole reduction
Over the past few decades, nanotechnology evolved into a significant, interdisciplinary research field on a global scale. Due to their extraordinary physicochemical, optical, and biological qualities, noble metal nanoparticles like gold, silver, palladium, and platinum are widely used in a variety of industrial and pharmaceutical procedures. In this study, a quick, low-cost, and environmentally friendly approach was used to create GAgNPs. Without using hazardous chemical substances, GAgNPs were produced using Phoenix dactylifera seeds extract as a reducing and stabilizing agent. The synthesized GAgNPs were characterized by UV-Visble, X-ray diffraction, and scanning electron microscopy. The presence of GAgNPs confirmed by the appearance of peak at 420 nm employing UV-Vis method, also affirmed by X-ray diffraction pattern, and the calculated size was about 28.72 nm. The electrochemical activity of GAgNPs was investigated through the elaboration of carbon paste-based sensor for the determination of ornidazole. The GAgNPs modified carbon paste electrode displayed a linear concentration range from 1.0 × 10−3 mol L−1 to 5.0 × 10−5 mol L−1 with a detection limit and quantification limit of 3.8 × 10−6 mol L−1 and 1.2 × 10−5 mol L−1, respectively. The proposed sensor was used for ornidazole analysis in milk samples, providing satisfactory recoveries of 105.7% and 102.7% with RSD below 4%