Current Analytical Chemistry - Volume 8, Issue 4, 2012

Reactive oxygen species (ROS) are very unstable molecules generated during the metabolism. They can be produced in excess, contributing to cellular dysfunctions. Antioxidants are substances that play an important role as a health-protecting factor, limiting the lesions caused by ROS. Two kinds of electrochemical biosensors based on ROS have been described to evaluate the antioxidant capacity in the food industry. The fir Read More

Phenolic compounds are important components of many fruits, vegetables and beverages, contributing to their flavor, color and sensory properties. Besides, they are associated with prevention of diseases thought to be induced by oxidative stress, such as cardiovascular diseases, cancer and inflammation. Due to their bioactive functions, phenolic compounds have received particular attention in recent years. Amo Read More

The introduction of instrumentation based on microfluidic technologies has revolutionised many areas of life sciences, including genomics and proteomics amongst others. As the role of reactive oxygen species has more recently been linked to an important number of pathologies, such as cancer or cardiovascular disease, this particular field of study has not been the exception in adopting these new technologies. Added int Read More

Polyphenolic compounds, which are widely distributed in plant-derived foods, recently attracted much attention because of their possible health benefits arising from their antioxidant activity, such as free radical scavengers and inhibition of lipoprotein oxidation. The detection of phenolic substances in food samples has been performed for many methods among them electrochemical sensors and biosensors approaches. P Read More

Vascular generation of nitric oxide (NO) plays an important role in the regulation of blood flow, and is counterbalanced by the formation of radical oxygen species (ROS). Thus, an imbalance in vascular NO and ROS production contributes to endothelial dysfunction, which is associated with cardiovascular disease. Here we review the main and commonly used methods that have been applied to determine vascular NO and R Read More

Recent advances in nanotechnology provide exciting opportunities for the development of novel and improved technologies for the detection of relevant molecules in food. Nanoparticle based analytical technologies are rapidly emerging at the intersection between analytical chemistry, nanotechnology and the food industry. This review discusses recent advances in the use of nanoparticles and nanostructures for develo Read More

Different degrees of glycosaminoglycan sulfation result in their different charge densities. The charge density differences impact their migration behavior in polyacrylamide gel electrophoresis and size exclusion chromatography, two of the most common methods for determining relative molecular masses of polysaccharides. In this study, we investigated the feasibility of using commercially available heparin oligosacchari Read More

This work describes a simple and sensitive method for the concurrent determination of sumatriptan (SUM) and naproxen (NAP) in dosage forms and human plasma using LC/MS and internal standardization. The drugs were separated isocratically on a C18 column using a binary mobile phase composed of water and acetonitrile at 0.05 % acetic acid. The method was validated over a linearity range of 10-900 ng/mL and 0.1-10 Read More

This work describes an electroanalytical method for simultaneous determination of cadmium (II) and lead (II) ions using a carbon paste modified with carbon nanotubes and an ion exchange synthetic resin (Amberlite IR120) electrode under Differential Pulse Anodic stripping voltammetric (DPASV) conditions. The procedure is based on the effective preconcentration of metal ions on the electrode surface containing ion exch Read More

Gemifloxacin (GMF) is a broad-spectrum quinolone antibacterial agent used in the treatment of acute bacterial exacerbation of chronic bronchitis and mild-to-moderate pneumonia. The investigation of the GMF - double-stranded DNA (dsDNA) interaction using an electrochemical DNA-biosensor, showed for the first time clear evidence of interaction with dsDNA. The interaction between GMF and dsDNA onto pencil grap Read More

An electrochemical biosensor was developed based on formaldehyde dehydrogenase immobilized with Nafion membrane for determination of formaldehyde in fish. The enzyme was immobilized through the entrapment technique and measured based on the reduction of β-nicotinamide adenine dinucleotide. The response time of the formaldehyde biosensor was <1 min, with an optimum pH of 8. The optimum enzyme lo Read More

A fast and effective microextraction technique is proposed for the determination of trace amounts of Cr(III) in water samples, using ultrasound-assisted emulsification-microextraction (USAEME) followed by flame atomic absorption spectrometry (FAAS). In the proposed approach, sodium diethyldithiocarbamate trihydrate solution (NaDDTC.3H2O) was used as a chelating agent and chloroform was selected as extraction sol Read More

The retention behavior of homo-oligonucleotides was investigated in ion-pair reverse-phase high-performance liquid chromatography (IP-RPLC). Rectification of retention time was performed by introducing the concept of “standard column” with double-point retention time correction (DP-RTC) using two anchor oligonucleotides as internal standards to ensure the accuracy of the retention measurement. Through polynomial fittin Read More

Silver doped LiFePO4 powder was synthesized using the hydrothermal method, and was used as a sensing material. An Optical WaveGuide (OWG) sensor which reacted to Volatile Organic Compound (VOC) was developed by spin-coating a thin film of LiFe0.99Ag0.01PO4 onto a Tin-diffused glass optical waveguide. This OWG sensor was used to detect formaldehyde gas as a typical example of VOCs. The experimental result showe Read More

Molecularly imprinted polymers were synthesized to screen suitable functional monomers for the detection of organochlorine pesticides, heptachlor and DDT. Three functional monomers i.e., methacrylic acid (MAA), 4-vinyl pyridine (4VP) and styrene were investigated. Rebinding experiments show that while MAA is best for the detection of heptachlor, 4-vinyl pyridine suits well for DDT. The experimental findings are corroborat Read More

This paper describes the development and validation of an isocratic LC-UV method for the assay of sitagliptin phosphate in tablets, a drug recently approved for the treatment of type 2 diabetes mellitus (DM). The method employs a Phenomenex® C18 column (150mm x 4.6mm I.D., 5μm) with 0.025 M phosphate buffer pH 6.8: acetonitrile (60:40, v/v) as mobile phase, at a 0.8 mL min-1 flow rate and UV detection at 267 nm. The Read More

Reversed zirconia-based stationary phases belong among interesting alternatives of widely used RP silica phases. Zirconia displays specific surface properties, which are responsible for a unique retention mechanism. Furthemore, it is necessary especially for acidic analytes to add a strong Lewis base to the mobile phase mainly to improve the separation efficiency. However, commonly recommended strong Lewis base buffers are Read More