Gel filtration chromatography

Gel-filtration chromatography is a popular and versatile technique that permits the effective separation of proteins and other biological molecules in high yield. Here, the basis of the method is described and typical matrix types are contrasted. The selection of suitable operating conditions and applications of the method are also discussed

Chromatography of beer

The objectives of the review are the collection, concise description and evaluation of the various chromatographic techniques used for the separation and quantitative determination of macro- and microcomponents present in beers

A liquid chromatography tandem mass spectrometry method for simultaneous analysis of 46 atmospheric particulate-phase persistent organic pollutants and comparison with gas chromatography/mass spectrometry,

A novel multi-analyte method for the simultaneous determination of 46 compounds of environmental concern, most of them belonging to the category of persistent organic pollutants, was developed using high-performance liquid chromatography and the results were compared to those obtained by gas chromatography. This study was performed in perspective of a cumulative exposure assessment of substances of health concern in environments where high levels, relatively to airborne particulate matter, can be found. The target compounds included polychlorinated biphenyls, brominated flame-retardants and derivatives of polycyclic aromatic hydrocarbons. The multi-analyte method was evaluated in air particulate matter in terms of reproducibility, linearity, recovery, limits of detection and quantification and matrix effect. The recovery was above 70% for all the analytes, whereas limits of quantification ranged between 23 and 390 pg.m(-3) in liquid chromatography and less than ten times in gas chromatography-mass spectrometry. Matrix effect was generally negligible for both the techniques, except the case of the detection of oxygenated derivatives of polycyclic aromatic hydrocarbons by gas chromatography

Pitfall in the high-throughput quantification of whole blood cyclosporin A using liquid chromatography-tandem mass spectrometry

In a growing number of laboratories the technique of liquid chromatography-tandem mass spectrometry is used for the quantification of cyclosporin A in whole blood, employing cyclosporin D as the internal standard. Cyclosporin A is extensively metabolized in vivo; in liquid chromatography-tandem mass spectrometry respective metabolites can give rise to both parent and product ions that are isobaric with ions commonly used for the detection of cyclosporin A and cyclosporin D, respectively. In this article it is demonstrated that limited chromatography with co-elution of such metabolites together with cyclosporin A and cyclosporin D can lead to incorrect results

Self-interaction chromatography as a tool for optimizing conditions for membrane protein crystallization

The second virial coefficient, or B value, is a measurement of how well a protein interacts with itself in solution. These interactions can lead to protein crystallization or precipitation, depending on their strength, with a narrow range of B values (the `crystallization slot') being known to promote crystallization. A convenient method of determining the B value is by self-interaction chromatography. This paper describes how the light-harvesting complex 1-reaction centre core complex from Allochromatium vinosum yielded single straight-edged crystals after iterative cycles of self-interaction chromatography and crystallization. This process allowed the rapid screening of small molecules and detergents as crystallization additives. Here, a description is given of how self-interaction chromatography has been utilized to improve the crystallization conditions of a membrane protein

Preliminary qualitative screening for cancer chemopreventive agents in Telfairia occidentalis Hook.f., Gnetum africanum Welw., Gongronema latifolium Benth. and Ocimum gratissimum L. from Nigeria

The leaves of four plant foods commonly consumed in Nigeria namely Gnetum africanum (Igbo name: Ukazi), Gongronema latifolium (Igbo name: Utazi), Telfairia occidentalis (Igbo name: Ugu), Ocimum gratissimum (Igbo name: Nchoanwu), were each screened for the presence of known potential chemopreventive agents using paper chromatography, thin layer chromatography and various chemical tests. All four vegetables showed the presence of phenolic compounds, flavonoids, phytosterols, tannins, saponins, chlorophyll and glycosides. Only Telfairia occidentalis and Gnetum africanum showed traces of alkaloids

Continuous preparative thin-layer chromatography

A short survey of preparative chromatographic methods is given. An apparatus for general use in continuous preparative thin-layer chromatography is described, and its performance compared with some related preparative techniques