Influence of the Specific Surface Area of Graphene Nanoplatelets on the Capacity of Lithium-Ion Batteries.

In order to understand the influence of the morphological properties of graphene materials on the electrochemical performance of electrodes for lithium-ion batteries, three different graphene nanoplatelets with the increasing specific surface area (NP1: 296 m g, NP2: 470 m g, and NP3: 714 m g) were added in the electrode formulation in different ratios. Higher specific surface area graphene nanoplatelets (NP3) exhibit reversible capacity up to 505 mA h g in the first discharge cycle (29.5% higher than that of graphite).

Flexible and Conductive Bioelectrodes Based on Chitosan-Carbon Black Membranes: Towards the Development of Wearable Bioelectrodes.

Wearable sensors for non-invasive monitoring constitute a growing technology in many industrial fields, such as clinical or sport monitoring. However, one of the main challenges in wearable sensing is the development of bioelectrodes via the use of flexible and stretchable materials capable of maintaining conductive and biocompatible properties simultaneously. In this study, chitosan-carbon black (CH-CB) membranes have been synthesized using a straightforward and versatile strategy and characterized in terms of their composition and their electrical and mechanical properties.

Enzymatic Glucose-Based Bio-batteries: Bioenergy to Fuel Next-Generation Devices.

This article consists of a review of the main concepts and paradigms established in the field of biological fuel cells or biofuel cells. The aim is to provide an overview of the current panorama, basic concepts, and methodologies used in the field of enzymatic biofuel cells, as well as the applications of these bio-systems in flexible electronics and implantable or portable devices. Finally, the challenges needing to be addressed in the development of biofuel cells capable of supplying power to small size devices with applications in areas related to health and well-being or next-generation portable devices are analyzed.

A novel sensor for monitoring of iron(III) ions based on porphyrins.

Three A(3)B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore).

Anserine and carnosine determination in meat samples by pure micellar liquid chromatography.

Anserine and carnosine, which are both imidazole dipeptides, are natural antioxidants that are present in some types of meat. A pure micellar liquid chromatographic procedure was developed using a micellar mobile phase of 0.10 M sodium dodecyl sulphate buffered at pH 7, an amino column and UV detection.

Solute-solvent interactions in micellar liquid chromatography. Characterization of hybrid micellar systems of sodium dodecyl sulfate-pentanol.

The solvation parameter model has been applied to the characterization of hybrid micellar chromatographic systems with mixtures of sodium dodecyl sulfate (SDS) and pentanol as mobile phases. Retention factors for 22 compounds in two groups, phenethylamines and antihistamines, were used for the characterization of the systems after the calculation of their Abraham descriptors. Three equations were developed as multiple linear regressions using Abraham descriptors and properties, such as log Poct and polar surface area to correlate the retention factors.

Amitriptyline and nortriptyline serum determination by micellar liquid chromatography.

Introduction: Amitriptyline and nortriptyline are tricyclic antidepressants which act by enhancing the actions of norepinephrine and serotonin caused by blocking the re-uptake of various neurotransmitters at the neuronal membrane. A micellar liquid chromatographic procedure was developed to determine these drugs in serum samples for use in clinical monitoring.

Methods: The chromatographic determination of these highly hydrophobic substances was carried out using a 0.

Monitoring bronchodilators with direct injection.

A procedure was developed for the determination of caffeine and theophylline using a C18 column (5 microm, 250 mm x 4.6 mm) and micellar liquid chromatography using hybrid mobile phases containing sodium dodecyl sulfate (SDS) and propanol, butanol or pentanol as modifiers. Detection was performed with a variable wavelength UV-vis detector at 272 nm.

Direct injection determination of benzoylecgonine, heroin, 6-monoacetylmorphine and morphine in serum by MLC.

A simple and sensitive direct injection chromatographic procedure is developed for the determination of heroin, two of its metabolites (morphine and 6-monoacetylmorphine (6-MAM)), and benzoylecgonine (a metabolite of cocaine) in serum samples. The proper resolution of the four substances is obtained with a chemometrics approach, where the retention is modelled as a first step using the retention factors obtained in a limited number of mobile phases. Afterwards, an optimisation criterion that takes into account the position and shape of the chromatographic peaks is applied.

Simultaneous determination of three opiates in serum by micellar liquid chromatography using direct injection.

A simple and reliable micellar liquid chromatographic method was developed for the simultaneous determination of 3 opiates (codeine, morphine, and thebaine) in serum, using direct injection and ultraviolet detection. The separation of the drugs was optimized on a C18 column, thermostatically controlled at 25 degrees C, by evaluating mobile phases containing sodium dodecyl sulfate (SDS) and various modifiers (propanol, butanol, or pentanol). Adequate resolution of the opiates was obtained with a chemometrics approach, in which retention was modeled as a first step by using the retention factors for several mobile phases.

Therapeutic monitoring of imipramine and desipramine by micellar liquid chromatography with direct injection and electrochemical detection.

A micellar liquid chromatographic (MLC) procedure was developed for the clinical monitoring of imipramine and its active metabolite, desipramine. The determination of these highly hydrophobic substances was carried out after direct injection of the serum samples using a mobile phase composed of 0.15 m SDS--6% (v/v) pentanol buffered at pH 7, pumped at 1.

Micellar liquid chromatography in clinical chemistry: application to the monitorization of B6 vitamins.

Background: A micellar reversed-phase liquid chromatographic procedure was developed for the determination of B6 group vitamins, i.e. pyridoxine, pyridoxal and pyridoxamine, in human serum.

Micellar liquid chromatography determination of B vitamins with direct injection and ultraviolet absorbance detection.

A micellar reversed-phase liquid chromatographic procedure was developed for the control of five water-soluble vitamins, B (nicotinamide), B1 (thiamine), B2 (riboflavin), B6 (pyridoxine and pyridoxamine), in multivitamin pharmaceutical formulations (capsules, pills and syrups). Optimization procedure includes studies about the composition of the mobile phase (sodium dodecyl sulphate and the modifiers propanol, butanol or pentanol), flow-rate and temperature. Chromatographic analysis of all vitamins was carried out using a single mobile phase of 0.

Determination in serum of some barbiturates using micellar liquid chromatography with direct injection.

A procedure was developed for the determination of several barbiturates, amobarbital, barbital, hexobarbital, and secobarbital, using a C18 column (120 x 4.6mm) and micellar liquid chromatography (MLC) mobile phases containing sodium dodecyl sulfate (SDS) and propanol, butanol, or pentanol as a modifier, with UV detection at 230nm. After the application of an interpretative strategy of optimization, the four barbiturates can be resolved and determined in serum samples, allowing the direct injection in 0.

Direct injection micellar liquid chromatographic determination of benzodiazepines in serum.

A simple micellar liquid chromatographic (MLC) procedure is reported for the determination of several benzodiazepines in serum: bromazepam, diazepam, flunitrazepam, halazepam, medazepam, nitrazepam, oxazepam and tetrazepam. The optimization studies have been made in C(18) and C(8) columns, using solutions containing sodium dodecyl sulphate (SDS) modified with butanol or pentanol as mobile phases. The method proposed for the determination of the benzodiazepines uses a hybrid micellar mobile phase of 0.

Therapeutic drug monitoring of anticonvulsant drugs by micellar HPLC with direct injection of serum samples.

Background: We developed a micellar liquid chromatographic (MLC) procedure for the determination of three extensively monitored antiepileptics in serum samples: carbamazepine, phenobarbital, and phenytoin.

Methods: We determined the composition of the mobile phase after modeling the elution behavior of the antiepileptics in hybrid micellar mobile phases of sodium dodecyl sulfate (SDS) with different organic modifiers (propanol, butanol, or pentanol) in an experimental design that used five mobile phases, a C(18) column, and ultraviolet detection. In the micellar chromatographic system, the serum samples can be injected directly.