We describe a liquid-chromatographic method for simultaneously determining norepinephrine, epinephrine, dopamine, and serotonin in 0.5 mL of human plasma. These analytes are purified on boric acid gel from Aldrich, separated on a reversed-phase C18 column, and detected electrochemically at +600 mV. Absolute recoveries of internal standards were 84% for 3,4-dihydroxybenzylamine and 57% for N-met...

a simple, reproducible and rapid gas chromatographic method for precise determination of valproic acid (vpa) in human plasma has been developed. total time for sample preparation and gc analysis is less than 45 min. after plasma protein precipitation, vpa was extracted into chloroform with suitable recovery. by using stabilwax®-da capillary gc column, a symmetrical gas chromatographic peak was ...

The engineering considerations common to large scale chromatographic purification of proteins are reviewed. A discussion of the industrial chromatography fundamentals is followed by aspects which affect the scale of separation. The separation column geometry, the effect of the main operational parameters on separation performance, and the physical characteristics of column packing are treated. ...

The enantiomers separation of thirteen drugs collected in Ch.P2010 was performed on chiral stationary phase of cellulose ramification (chiralpak OD and chiralpak OJ) by high performance liquid chromatographic (HPLC) methods, which included ibuprofen (C1), ketoprofen (C2), nitrendipine (C3), nimodipine (C4), felodipine (C5), omeprazole (C6), praziquantel (C7), propranolol hydrochloride (C8), ate...

As magmas rise toward the surface, they traverse regions of the mantle and crust with which they are not in equilibrium; to the extent that time and the intimacy of their physical contact permit, the melts and country rocks will interact chemically. We have modeled aspects of these chemical interactions in terms of ion-exchange processes similar to those operating in simple chromatographic colu...

Peak parking experiments were conducted to study the chromatographic behavior in a RPLC system consisting of a column packed with superficially porous C(18)-particles and a mixture of methanol and water (70/30, v/v). The values of the surface diffusion coefficient and the retention equilibrium constant of a column packed with superficially porous C(18)-particles were comparable to those of col...

An automated column-chromatographic system for stepwise elution of lipids is described. The automation is achieved with commercially available snap-on modules and Teflon valves.

An uncontrolled used of antibiotics and sulphonamides is responsible for the presence of residues in beehive products and contributes to the problem of food safety. The optimisation of analytical methods for the detection of residues of antibacterial drugs (sulphonamides, SPs; tylosin, TL; streptomycin, ST) in honey was pursued and the methods applied to routine samples. ST was investigated by ...

The goal of this work was to provide a technical solution for the automated optimization multi-column systems protein separation and fractionation. Both algorithm software that can be downloaded are provided. In algorithm, length order individual column segments considered. Various solutions provided by including i) obtain uniform peak distribution, ii) park different species at inlet segments,...

Liquid chromatography combined with electrospray ionization is widely used for direct analysis of polar and labile molecules by LCMS. The on-line coupling in LCMS is a major strength but also causes a principal limitation that each eluting analyte has to be analyzed immediately and is not available for detailed interrogation after the LCMS run. Here we developed a new chromatographic strategy, ...