Liquid column chromatography

A common liquid chromatography column is somewhat larger in diameter than a nanocolumn. Consequently, the flow of solution along such a column is measured in terms of one or two milliliters per minute, and spraying requires the aid of a gas flowing concentrically around the end of the inlet tube (Figure 10.2c). An electrical potential is still applied to the end of this tube to ensure adequate electrical chaiging of the droplets. 

These factors make it necessary to reduce the amount of solvent vapor entering the flame to as low a level as possible and to make any droplets or particulates entering the flame as small and of as uniform a droplet size as possible. Desolvation chambers are designed to optimize these factors so as to maintain a near-constant efficiency of ionization and to flatten out fluctuations in droplet size from the nebulizer. Droplets of less than 10 pm in diameter are preferred. For flow rates of less than about 10 pl/min issuing from micro- or nanobore liquid chromatography columns, a desolvation chamber is unlikely to be needed. 

Schematic diagram of an orthogonal Q/TOF instrument. In this example, an ion beam is produced by electrospray ionization. The solution can be an effluent from a liquid chromatography column or simply a solution of an analyte. The sampling cone and the skimmer help to separate analyte ions from solvent, The RF hexapoles cannot separate ions according to m/z values and are instead used to help confine the ions into a narrow beam. The quadrupole can be made to operate in two modes. In one (wide band-pass mode), all of the ion beam passes through. In the other (narrow band-pass mode), only ions selected according to m/z value are allowed through. In narrow band-pass mode, the gas pressure in the middle hexapole is increased so that ions selected in the quadrupole are caused to fragment following collisions with gas molecules. In both modes, the TOF analyzer is used to produce the final mass spectrum.

In dynamic FAB, this solution is not stationary but flows steadily over the target area. Usually, the liquid flow is the eluant from a liquid chromatography column, but it need not be. 

R. P. W. Scott, Small Pore Liquid Chromatography Columns—Their Properties and Uses, Wiley-Interscience, John Wiley Sons, Inc., New York, 1984. 

Application of the Design Equations to Packed Liquid Chromatography Columns and Open Tubular Gas Chromatography Columns... 

M"Liquid Chromatography Column Theory", R.P.W.Scott, John Wiley and Sons, Chichester-New York-Brisbane-Toronto-Singapore, (1992). 

Performance Characterization of Liquid Chromatography Columns Using Reduced Parameters... 

R. P. N. Scott (Ed.), "Small Bore Liquid Chromatography Columns", Wiley, New York, NY, 1984. 

Dapremont, O., Cox, G.B., Martin, M., Hilaireau, P., and Colin, H., Effect of radial gradient of temperature on the performance of large-diameter high-performance liquid chromatography columns I. Analytical conditions,. Chromatogr. A, 796, 81, 1998. 

R. Ricker, L. Sandoval, B. Permar, and B. Boyes, Improved reversed-phase high performance liquid chromatography columns for biopharmaceutical analysis, J. Pharmaceut. Biomed. Anal., 14, 93 (1995). 

Vol. 66 Solid Phase Biochemistry Analytical and Synthetic Aspects. Edited by William H. Scouten Vol. 67 An Introduction to Photoelectron Spectroscopy. By Pradip K. Ghosh Vol. 68 Room Temperature Phosphorimetry for Chemical Analysis. By Tuan Vo-Dinh Vol. 69 Potentiometry and Potentiometric Titrations. By E. P. Serjeant Vol. 70 Design and Application of Process Analyzer Systems. By Paul E. Mix Vol. 71 Analysis of Organic and Biological Surfaces. Edited by Patrick Echlin Vol. 72 Small Bore Liquid Chromatography Columns Their Properties and Uses. Edited by Raymond P.W. Scott... 

Lamprecht, G., Kraushofer, T., Stoschitzky, K., Lindner, W. (2000). Enantioselective analysis of (R)- and (S)-atenolol I urine samples by a high-performance liquid chromatography column-switching setup. J. Chromatogr. B 740, 219-226. 

Donovan, S.F., Pescatore, M.C. (2002) Method for measuring the logarithm of the octanol-water partition coefficient by using short octadecyl-poly(vinyl alcohol) high-performance liquid chromatography columns. J. Chromatogr. A, 952, 47-61. 

Shimoishi [ 555 ] determined selenium by gas chromatography with electron capture detection. To 50-100 ml seawater was added 5 ml concentrated hydrochloric acid and 2 ml 4-nitro-o-phenylenediamine (1%) and, after 2 hours, the product formed was extracted into 1 ml of toluene. The extract was washed with 2 ml of 7.5 M hydrochloric acid, then a sample (5 pi) was injected into a glass gas-liquid chromatography column (lm x 4 mm) packed with 15% of SE-30 on Chromosorb W (60-80 mesh) and operated at 200 °C with nitrogen (53 ml/min) as carrier gas. There is no interference from other substances present in seawater. The detection limit is 5 ng/1 with 200 ml samples, and the precision at a Se level of 0.025 pg/1 is 6%. 

At the heart of the system is a cartridge that houses 24 liquid chromatography columns. This cartridge enables multiple samples to be analyzed in parallel. The 24 incorporated columns may be packed with... 

A bottle of fizzy drink going flat is a fairly trivial example of partition, but the principle is vital to processes such as reactions in two-phase media or the operation of a high-performance liquid chromatography column. 

R.P.W. Scott, Liquid Chromatography Column Theory, Wiley, UK, ISBN 0 471 93305 8, 1992. 

A guard column is a short, less-expensive liquid chromatography column that is placed ahead of the analytical column in an HPLC system. The purpose of a guard column is to adsorb and retain mixture components that would contaminate the more expensive analytical column. In-line filters are relatively coarse filters (compared to prefilters) placed in the mobile phase line to filter out particulates that maybe introduced on-line, such as from sample injection. 

Figure 4.18 Analysis of anions in water using ion-pair liquid chromatography. Column, octadecyl-bonded silica gel, 15 cm x 4.6 mm i.d. eluent, 2 mM tetrabutyl-ammonium hydroxide (pH 5.3) in 3% acetonitrile-water flow rate, 1 ml min- detection, UV200 nm. Peaks 1, Br 2, N03 and3,1. ...

Figure 4.20 Calibration curves for size-exclusion liquid chromatography. Column, TSK GEL G3000SW, 120 cm x 7.5 mm i.d. eluent, 0.2 m sodium phosphate buffer pH 6.8 flow rate, 1.0 ml min-1. Standards 1, protein-, 2, dextran, and 3, polyethylene glycol.

Small Bore Liquid Chromatography Columns Their Properties and Uses. Edited by... 

Ogan, K. and Katz, E., Retention characteristics of several bonded-phase liquid-chromatography columns for some polycyclic aromatic hydrocarbons, J. Chromatogn, 188, 115, 1980. 

This chapter deals with the properties of high-pressure liquid chromatography columns. It is divided into two sections column physics and column chemistry. In the section on column physics, we discuss the properties that influence column performance, such as particle size, column length and column diameter, together with the effect of instrumentation on the quality of a separation. In the section on column chemistry, we examine in depth the surfaces of modern packings, as well as the newer developments such as zirconia-hased packings, hybrid packings or monoliths. We have also included a short section on... 

Mendez, A., Bosch, E., Roses, M. and Neue, U. D., Comparison of the acidity of residual silanol groups in several liquid chromatography columns. J. Chromatogr. A 986 33 4, 2003. 

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