Enhanced chemiluminescence determination of paracetamol.

Due to the severe consequences of potential overdoses of paracetamol (PCM) on the human body, the measurement of PCM in pharmaceutical and biological samples is essential. Therefore, a simple and rapid technique with a high detection limit and a wide linear range is presented here which plays a crucial role in detecting PCM's overdose leading to drug poisoning. This contribution illustrates a novel chemiluminescence (CL) system for the detection of PCM based on the chemiluminescence reaction between PCM and KMnO.

Determination of valproic acid in human plasma using dispersive liquid-liquid microextraction followed by gas chromatography-flame ionization detection.

Objectives: Dispersive liquid-liquid microextraction coupled with gas chromatography (GC)-flame ionization detector was developed for the determination of valproic acid (VPA) in human plasma.

Materials And Methods: Using a syringe, a mixture of suitable extraction solvent (40 µl chloroform) and disperser (1 ml acetone) was quickly added to 10 ml of diluted plasma sample containing VPA (pH, 1.0; concentration of NaCl, 4% (w/v)), resulting in a cloudy solution.

Vortex-assisted liquid-liquid extraction combined with field-amplified sample injection and sweeping micellar electrokinetic chromatography for improved determination of β-blockers in human urine.

A new micellar electrokinetic chromatography (MEKC) method was developed and validated for the analysis of carvedilol and propranolol in human urine samples. In this study, vortex-assisted liquid-liquid extraction (VALLE) coupled with field-amplified sample injection and sweeping was employed for biological sample clean-up and sensitivity enhancement in MEKC. After VALLE, the urine samples were analyzed by MEKC.

Simultaneous determination of some common food dyes in commercial products by digital image analysis.

A simple and relatively fast image-analysis method using digital images, obtained with a flatbed scanner, has been described. The method was used for the simultaneous determination of four common food dyes, namely, carmoisine, brilliant blue, sunset yellow, and quinoline yellow, in binary mixtures in commercial products without a need for any prior separation steps. The results obtained were validated against a standard high-performance liquid chromatography method and a good agreement was obtained.

Determination of five antiarrhythmic drugs in human plasma by dispersive liquid-liquid microextraction and high-performance liquid chromatography.

A fast and sensitive high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection was developed and validated for the simultaneous quantitation of five antiarrhythmic drugs (metoprolol, propranolol, carvedilol, diltiazem, and verapamil) in human plasma samples. It involves dispersive liquid-liquid microextraction (DLLME) of the desired drugs from 660 µL plasma and separation using isocratic elution with UV detection at 200 nm. The complete separation of all analytes was achieved within 7 min.

Detection limit enhancement of antiarrhythmic drugs in human plasma using capillary electrophoresis with dispersive liquid-liquid microextraction and field-amplified sample stacking method.

Background: A new capillary zone electrophoresis (CZE) with ultraviolet detection method has been developed and validated for the analysis of four antiarrhythmic drugs in human plasma samples.

Methods: In this study, a dispersive liquid-liquid microextraction (DLLME) coupled with field-amplified sample stacking (FASS) was employed for biological samples clean-up and sensitivity enhancement in CZE.

Results: Under optimum DLLME-FASS-CZE conditions, enhancement factors were in the range of 157-314.

Salt-assisted LLE combined with field-amplified sample stacking in CE for improved determination of beta blocker drugs in human urine.

Background: A simple and sensitive CE method was developed and validated for the analysis of some beta blockers in human urine.

Methods: In this study, salting-out assisted LLE combined with field-amplified sample stacking method was employed for biological sample clean-up and sensitivity enhancement in CE.

Results: Under the optimal conditions good linearity (r(2) ≥0.

Gold nanorods-enhanced rhodamine B-permanganate chemiluminescence and its analytical application.

A novel enhanced chemiluminescence system was developed by applying gold nanorods (Au NRs) as catalysts in rhodamine B-permanganate reaction. Au NRs with three different aspect ratios were synthesized by seed mediated growth method and characterized by UV-Vis spectra and transmission electron microscopy. It was demonstrated that Au NRs have much higher catalytic effect than spherical nanoparticles on rhodamine B-permanganate chemiluminescence reaction.

A highly sensitive RP-HPLC-fluorescence method to study aldehyde oxidase activity.

Aldehyde oxidase is a widely distributed enzyme that is involved in the metabolism of an extensive range of aldehydes and N-heterocyclic compounds with physiological, pharmacological, and toxicological relevance. In the present study, a highly sensitive RP-HPLC-fluorescence method based on the oxidation of phenanthridine to phenanthridinone has been developed and validated to assay aldehyde oxidase activity in biological samples. Determination of phenanthridinone was achieved on a C18 column using 10 mmol/L phosphate buffer (pH 5.

Simultaneous Determination of 6-Mercaptopurine and its Oxidative Metabolites in Synthetic Solutions and Human Plasma using Spectrophotometric Multivariate Calibration Methods.

Introduction: 6-Mercaptopurine (6MP) is an important chemotherapeutic drug in the conventional treatment of childhood acute lymphoblastic leukemia (ALL). It is catabolized to 6-thiouric acid (6TUA) through 8-hydroxo-6-mercaptopurine (8OH6MP) or 6-thioxanthine (6TX) intermediates.

Methods: High-performance liquid chromatography (HPLC) is usually used to determine the contents of therapeutic drugs, metabolites and other important biomedical analytes in biological samples.

A new multi-wavelength model-based method for determination of enzyme kinetic parameters.

Lineweaver-Burk plot analysis is the most widely used method to determine enzyme kinetic parameters. In the spectrophotometric determination of enzyme activity using the Lineweaver-Burk plot, it is necessary to find a wavelength at which only the substrate or the product has absorbance without any spectroscopic interference of the other reaction components. Moreover, in this method, different initial concentrations of the substrate should be used to obtain the initial velocities required for Lineweaver-Burk plot analysis.

Study of aldehyde oxidase-catalyzed metabolic pathway of phenanthridine using MCR-ALS method.

Evaluation of metabolic pathways is one of the challenging areas in biological and pharmaceutical sciences. Phenanthridine oxidation to phenanthridinone is used commonly to study aldehyde oxidase activity. This reaction could pass through phenanthridine N-oxide intermediate.

A novel spectrophotometric method for determination of kinetic constants of aldehyde oxidase using multivariate calibration method.

Although phenanthridine has been frequently used as a specific substrate for the assessment of aldehyde oxidase activity, the use of this method is questionable due to a lower limit of detection and its validity for kinetic studies. In the present study, a novel sensitive multivariate calibration method based on partial least squares (PLS) has been developed for the measurement of aldehyde oxidase activity using phenanthridine as a substrate. Phenanthridine and phenanthridinone binary mixtures were prepared in a dynamic linear range of 0.