Automatic liquid chromatography

Hatano, H., Sumizu, K., Rokushika, S., and Murakami, F. (1970). Automatic liquid chromatography of primary mono- and diamines on a cation-exchange resin. Arm . Biochem. 35, 377-383. 

The first approach to automatic liquid chromatography (LC) of amino acids (AAs) - known today as ion-exchange chromatography - was published by Spackman, Stein, and Moore in 1958, which led to the award of the Nobel Prize in 1972 to Stanford Moore and William H. Stein. Forty-five years later, it now takes less than 5 min (Figure 1) to separate and quantitate the essential protein AAs instead of 2 days. Early separations were carried out by postcolumn derivatizations. 

Multidimensional liquid chromatography encompasses a variety of techniques used for seunple separation, cleanup and trace enrichment [12,279-289]. A characteristic feature of these methods is the use of two or more columns for the separation with either manual or automatic switching by a valve interface of fractions between columns. These techniques require only minor modification to existing equipment, and of equal importance, enable the sample preparation and separation procedures to be completely automated. 

Two variations on the analysis of PCR products by ESI mass spectrometry have emerged (1) direct-injection MS and tandem mass spectrometry (MS-MS) and (2) liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS). In the former approach, the sample is cleaned manually, and as noted above, the cleanup is performed as simply and rapidly as possible. In the latter approach, the cleanup is done automatically... 

Size exclusion liquid chromatography M) has been widely used to characterize distributions of molecular weights in polymer specimens. This paper describes a package of computer programs for automatic data collection and data reduction in size exclusion liquid chromatography (2). The programs and the environment in which they operate are carefully tailored to emphasize the interaction between the user and his data rather than the Interaction between the user and the computer. The system we describe differs from that described by Koehler et al. (J) in that all functions are performed by a stand-alone system. 

Norbornadiene (from Koch-Light Ltd.) of purity greater than 99% was purified by distillation through a Normatron automatic still at a reflux ratio of 25 1. The fraction (60 vol%) boiling at 89.3 °C/998 mbar was collected [18] bp 89.5 °C/1013 mbar). Analysis by gas liquid chromatography (GLC) (Pye Unicam - with OVO-1 columns), showed one... 

It is now common to couple an instrument for separating a mixture of organic compounds e.g. using gas chromatography (GC) or high performance liquid chromatography (HPLC), directly to the input of a mass spectrometer. In this way, as each individual compound is separated from the mixture, its mass spectrum can be recorded and compared automatically with the library of known compounds and identified immediately if it is a known compound. 

James and Martin (49) reported on visual and automatic titration methods capable of detecting microgram quantities of acids and bases. This type of detection has the distinction of being the first type of detector used in gas-liquid chromatography. Electronically modified designs for improving the automation of the detector are possible. 

MM Delgado Zamarreno, A Sanchez Perez, MC Gomez Perez, J Hernandez Mendez. Directly coupled sample treatment—high-performance liquid chromatography for on-line automatic determination of liposoluble vitamins in milk. J Chromat A 694 399-406, 1995. 

Oliveira HM et al (2010) Exploiting automatic on-line renewable molecularly imprinted solid-phase extraction in lab-on-valve format as front end to liquid chromatography application to the determination of riboflavin in foodstuffs. Anal Bioanal Chem 397(1 ) 77-86... 

Boonjob W et al (2010) Online hyphenation of multimodal microsolid phase extraction involving renewable molecularly imprinted and reversed-phase sorbents to liquid chromatography for automatic multiresidue assays. Anal Chem 82(7) 3052-3060... 

Although these instruments are the most advanced of the automatic TLC systems, their cost might discourage widespread use. Column liquid chromatography has many advantages compared to the automatic TLC concept. 

An offline measurement apparatus is usually not directly mounted on the reactor, but is fed with samples withdrawn from it manually or automatically. This is the typical case of chromatography, a widely used measurement device for gas and liquid composition. Both gas and liquid chromatographies are based on the separation of the sample by means of selective adsorption on a solid substrate posed in a fixed bed column, and on the detection of the change of a suitable property of the (gas or liquid) carrier, usually thermal conductivity. 

Since ISEs can be used in continuous flow systems or in flow systems with sample injection (flow injection analysis, FIA)21 their application is wide, not limited to discrete samples. Analysis time becomes shorter, with faster recycling. Additionally, in flow systems the experimental assembly and data analysis can be controlled automatically by microcomputer, including periodic calibration. Another development is the use of sensors for the detection of eluents of chromatographic columns in high-pressure liquid chromatography (HPLC). Miniaturization has permitted an increase in the use of sensors in foods, biological tissues, and clinical analyses in general. 

Automated methods frequently exhibit remarkable performance not only in terms of sample throughput and cost, but in relation to the quality of results, especially in relation to repeatability and reproducibility. Several systems are currently available that enable simple automation of manual gestures these include automatic titra-tors, pH-meters with a circulating cell, etc., and involve approaches that are not fundamentally different to the corresponding manual method. These techniques are not, however, described in this chapter, nor are gas and liquid chromatography and capillary electrophoresis, automated techniques, that may be present but are not routinely used in oenological laboratories. 

Chromatography. Filtered polysaccharide solutions were analyzed using an SEC system consisting of an automatic sampler (Waters WISP, Waters, Milford, MA) with a high-performance liquid chromatography pump (Waters model 590), pulse dampener (Viscotek, Houston, TX), viscometer... 

Cl. Chilcote, D. D., and Mrochek, J. E., Use of automatic digital data acquisition and on-line computer analysis in high-resolution liquid chromatography. Clin. Chem. 17, 751-756 (1971). 

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