Towards using high-performance liquid chromatography at home

An affordable gradient mixer for chromatography with aqueous and organic solvents

A gradient mixer for preparative column chromatography has been developed, using a microcontroller, a three-way solenoid valve, and a one-channel pump of any chosen design, controlled by a microcontroller and with specifications for the gradient entered through a touchscreen. The gradient mixer is economical and can be produced with the design files provided.

Peak broadening caused by using different micro-liquid chromatography detectors

Advancements in column technology resulted in smaller particles and more efficient phases. In parallel, the use of columns with reduced dimensions is becoming more common. This means the effective column volume is also decreased, thereby making the systems more susceptible to effects of band broadening due to extra-column volume. Despite these trends and the fact that a growing number of miniaturized liquid chromatography systems are being offered commercially, manufacturers often stick to the modular concept with dedicated units for pumps, column oven, and detectors. This modular design results in long connection capillaries, which leads to extra-column band broadening and consequently prevents the exploitation of the intrinsic efficiency of state-of-the-art columns. In particular, band broadening post column has a considerable negative effect on efficiency. In this study, mass flow and concentration-dependent detectors were examined for their influence on band broadening using a micro-LC system. A mass spectrometric detector, an evaporative light scattering detector, two UV detectors, and a previously undescribed fluorescence detector were compared. The influence on efficiency is compared using plate height vs linear velocity data and peak variance. It is shown that an increase in the inner diameter after the post-column transfer capillary leads to significant loss in plate height. Comparing the UV detectors, it could be shown that the dispersion was reduced by 38% by the reduction of the post-column volume. The largest variance was found for the evaporative light scattering detector, which was 368% higher compared to the variance of the detector with the least effect on band broadening.

A Mini Review on Characteristics and Analytical Methods of Otilonium Bromide

Irritable bowel syndrome (IBS) is a world-wide disease prevalently in Western nations. It influences about 15% of the western populace, with a negative effect on the quality of life and furthermore on medical services costs. Anticholinergic antispasmodics are first line of treatment for discomfort or abdominal pain, particularly if unrelieved after alleviation of stoppage or antidiarrheal treatment. Otilonium bromide (OTB) is quaternary ammonium compound with action on distal GI tract as antispasmodic. It is utilized in the treatment of patients influenced by Irritable inside disorder (IBS) because of its particular pharmacokinetic and pharmacodynamic properties. OTB is poorly absorbed systematically was viable in contrast with different medications used for same purpose, for example, pinaverium bromide and mebeverine, with a good tolerability profile. The effects are long lasting, even after stopping the dosage regime for reduction of abdominal pain. In this review, an overview of mechanism of action, pharmacologic action, synthesis and particularly various analytical and bioanalytical methods are discussed. The analytical methods discussed are spectrophotometry including Near Infrared Spectroscopy (NIRS), chromatography and capillary electrophoresis methods are described with the range, limit of detection and quantification. The paper also provides details of scope of further extension of analytical methods. It was found that most of the analytical methods involves usage of toxic solvents e.g., methanol, acetonitrile, chloroform etc. posing risk to the analyst as well as environment.