Trace levels of cadmium, lead, and mercury heavy metals are toxic to the human nervous system. These metals occur naturally and as a result of inappropriate agricultural and industrial practices. In response to this problem, a novel modified electrode was constructed for the simultaneous determination of cadmium, lead, and mercury. The modified electrode was prepared by incorporating zirconium oxide nanoparticles (ZrO2 NPs) and multi-walled carbon nanotubes into a carbon paste electrode. Transmission electron microscopy and electrochemical impedance spectroscopy were employed for the characterization of the modified electrode. Different variables that affect the electrochemical response were studied and optimized. The proposed electrode exhibits a wide linear range and lower detection limits obtained were 2.77 x 10-10, 2.46 x 10-10 and 4.15 x 10-10 mol L−1 for cadmium, lead, and mercury, respectively. The method was successfully applied for the determination of these neurotoxic heavy metals in beef, milk, urine, plasma, and omega-3 capsules.
A green spectrofluorimetric method was introduced for the determination of selected genotoxic impurities; 2-aminopyridine and 3-aminopyridine in different pharmaceutical raw materials and dosage forms. The method relied on the native fluorescence of these impurities in acidic medium. The experimental conditions were carefully studied and optimized, and the method was validated according to International Council on Harmonisation (ICH) guidelines. The linear range for both analytes was 2.50–100 ng/mL with good determination coefficients of 0.9995 and 0.9992 and detection limits of 0.62 ng/mL and 0.74 ng/mL for 2-aminopyridine and 3-aminopyridine, respectively. The method was successfully applied for determination of 2-aminopyridine and 3-aminopyridine in four active pharmaceutical ingredients and nine dosage forms with satisfactory percentage recoveries and without interference from co-formulated excipients. Analytical performance of the proposed method was comparable to that of the reported methods; hence, the proposed method can be used as a simple and low-cost alternative in quality control laboratories.
Methylglyoxal (MGO) is a genotoxic α-dicarbonyl compound. Recently, it was found to be formed in glycerol preparations during storage through auto-oxidation. A simple fluorimetric determination of the carcinogenic degradation product of glycerol, MGO, was developed and validated. The proposed method is based on the derivatization of MGO with 4-carbomethoxybenzaldehyde (CMBA) and ammonium acetate to yield a fluorescent imidazole derivative that can be measured at 415 nm after excitation at 322 nm. The optimized conditions were determined to be 0.2 M CMBA, 1.0 M ammonium acetate and a reaction time of 40 min at 90 C using ethanol as diluting solvent. The linear range was 10.0-200.0 ng/ml. Detection and quantification limits were 2.22 and 6.72 ng/ml, respectively. The proposed method was validated according to International Council for Harmonisation (ICH) guidelines and compared with the reported method and no significant difference was found. It was successfully applied for the determination of MGO in six different glycerol-containing pharmaceutical preparations and dietary supplements.
Metformin is the most prescribed drug for diabetes. We aimed to develop a new HPLC method for determination of metformin and its main impurity 1-cyanoguanidine in raw material and its pharmaceutical tablets. The separation was achieved on pentabromobenzyl column using a mixture of 20% 10.0 mM phosphate buffer (pH 5.5) and 80% methanol as a mobile phase at a flow rate of 1.0 mL min -1 and UV detection at 227 nm. The analysis time was less than 4.0 minutes. The method was linear through concentration ranges of 3.0 -80 µg mL -1 and 0.5-10 µg mL -1 and detection limits of 0.73 µg mL -1 and 0.11 µg mL -1 for metformin and 1cyanoguanidine, respectively. The method was successfully applied for determination of metformin in bulk and pharmaceutical dosage forms. The high sensitivity of the developed method allowed for determination of 1-cyanoguanidine below its specified limits in metformin raw material and tablets.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.