Automated column

The separation of the polysaccharide components utilizes their different solubUities, polar groups, extents of branching, molecular weights, and molecular flexibUities and may be accompUshed batchwise or with easUy automated column techniques such as column or high performance Uquid chromatography. These procedures have been summarized in several reviews (3,141—143). 

M. Cavalleri, W. Pollini and L. Colombo, Determination of ramoplanin in human urine by high performance liquid cliromatography with automated column switching ,... 

J. R K. Huber and G. Lamprecht, Assay of neopterin in serum by means of two-dimensional high-performance liquid chromatography with automated column switching using tliree retention mechanism , 7. Chromatogr. B 666 223-232(1995). 

Section I of this book includes chapters on the principles and practice of PLC. After this introductory Chapter 1, Chapter 2 provides information on efforts undertaken to date in order to establish the theoretical foundations of PLC. With growing availability and popularity of modem computer-aided densitometers, separation results can be obtained in digital form as a series of concentration profiles that can be relatively easily assessed and processed. From these, relevant conclusions can be drawn in exactly the same manner as in automated column chromatographic techniques. Efforts undertaken to build a theoretical foundation of PLC largely consist of adaptation of known strategies (with their validity confirmed in preparative column liquid chromatography) to the working conditions of PLC systems. 

High-performance liquid chromatographic system equipped with an automated column switching system... 

An HPLC system equipped with an ultraviolet/diode-array detector (UV/DAD) and automated column switching system is used. 

ViUeneuve, M.S., Anderegg, R.J. Analytical supercritical fluid chromatography using fully automated column and modifier selection valves for the rapid development of chiral separations. J. Chromatogr. A 1998, 826, 217-225. 

Higher-specificity techniques such as immunoaffinity chromatography have been also found widespread acceptance for the determination of chloramphenicol residues in edible animal products. The first pertinent reports concerned the determination of chloramphenicol residues in swine muscle (60) and milk and eggs (21). Alternative immunoaffinity chromatography procedures were suggested later for exiraction/preconcentration of chloramphenicol residues from swine tissues (50), or for online immunoaffinity extraction for the determination of chloramphenicol in milk and swine muscle by an automated column-switching system (22). 

Liquid chromatography cleanup on a LiChrosorb Diol column has been further proposed for the offline purification of chloramphenicol residues from bovine muscle and eggs (32). An online approach based on reversed-phase principles has also been described for isolation of chloramphenicol residues from swine kidney by an automated column switching system (63). Use of a protein exclusion column (Hisep) has been also suggested in an online trace-enrichment method for the determination of chloramphenicol in animal tissues (52). By employing a column-switching system, all chloramphenicol that eluted from the protein exclusion column was trapped at the entry of a 5 m Supelcosil LC-18 preconcentration column, to be subsequently back-flashed into the analytical column. 

Boppana V, Miller-Stein C, Schaefer WH (1996) Direct plasma liquid chromatographic-tandem mass spectrometric analysis of granisetron and its 7-hydroxy metabolite utilizing internal surface reversed-phase guard columns and automated column switching devices. J Chromatogr B 678 227-236... 

This robotic sample preparation and counting technology, together with mechanical improvements in the chemical separation system, has resulted in an automated column chromatography system that can run almost autonomously, whereas several people were required to operate the ARCA II system for a transactinide chemistry experiment. 

R. A. Kenley, S. Chandry, and G. C. Visor, An automated column-switching HPLC method for analyzing active and excipient materials in both cream and ointment formulations, Drug Dev. Ind. Pharm., 4 1781 (1985). 

As in any chromatography technique, one can break down the separation process to its two most fundamental aspects adsorption and elution. On a more practical level, the execution of an IMAC experiment involves hve discrete steps which can be readily automated column equilibration (charging of the gel), sample loading, removal of unbound material (washing), elution, and regeneration. 

Thanh, H.H. Andresen, A.T. Agasoster, T. Rasmussen, K.E. Automated column-switching high-performance liquid-chromatographic determination of flumequine and oxolinic acid in extracts from fish. J. Chromatogr. 1990, 532, 363-373. 

Czech, M. A., Meltzer, M. and Mouskountakis, J. Determination of Ro 14-4767 (Loceryl) by LC using automated column switching with ultraviolet and electrochemical detection. J. Pharm. Biomed. Anal. 9 1019-1029, 1991. 

Cohen, B. L. Automated column and solvent selection for fully automated HPLC analyses of tablet content uniformity. /. Chromatogr. Sci. 25(5) 202-205, 1987. 

Villeneuve, M.S. Anderegg, R.J. Analytical Supercritical Fluid Chromatography Using Fully Automated Column and Modifier Selection Valves for the Rapid Development of Chiral Separations, 7. Chromatogr. A 826, 217-225 (1998). 

Boppana, V.K. Miller-Stein, C. Schaefer, W.H. Direct Plasma Liquid Chromatographic-Tandem Mass Spectrometric Analysis of Ganisetron and its 7-Hydroxy Metabolite Utilizing Internal Surface Reversed-Phase Guard Columns and Automated Column-switching Devices, J. Chromatogr. B. 678, 227-236 (1996). 

No IS, no sample preparation except automated column-switching C4-alkyldiol-silica restricted access SPE column... 

Perhaps 90% of all rHPLC separations use a Cig stationary phase. In SFC, there is a much wider choice. The vast majority of SFC separations have been performed on totally porous silica, usually with a bonded organic phase. A full range of achiral stationary phases is available for use in SFC. The most common are silica, cyano, amino, and diol. Several relatively new phases, such as an ethyl pyridine phase, promise to decrease the need for additives in the mobile phase. Almost everything elutes from cyano columns. Diol and bare silica often give the best selectivity for acids and alcohols. Amino is often more retentive but also often yields the best selectivity for amines. Although any of these columns is likely to give a reasonable separation, the use of an automated column selection valve, along with a solvent selection valve, makes it easy to find the one with the best selectivity for a specific application. 

Lindegard, B., Bjork, H., Jonsson, J. A., Mathiasson, L., Olsson, A. M. (1994). Automated column liquid chromatographic determination of a basic drug in blood plasma using the supported liquid membrane technique for sample pretreatment. Anal. Chem., 66, 4490-7. 

Simon P, Nicot T. 1993. Automated column-switching high-performance liquid chromatography for the determination of 2-thiothiazolidine-4-carboxylic acid in urine. J Chromatogr 620 47-53. 

Snippe, N. Van de Merbel, N.C. Ruiter, F.P.M. Steijer, O.M. Lingeman, H. Brinkman, UA.T. Automated column liquid chromatographic determination of amoxicihin and cefadroxil in bovine serum and muscle tissue using on-line dialysis for sample preparation. J.Chromatogr.B, 1994, 662, 61-70 [serum muscle cow post-column reaction LOD 50 ng/mL LOD 200 ng/g SPE extracted cefadroxil dialysis]... 

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