Narrow bore HPLC

S. Porter and N. Johnston, The application of narrow-bore HPLC columns to the analysis of veterinary drugs, in Proceedings of the EuroResidue II Conference, pp. 538-542 (1993). 

T. Cserhati, E. Forgacs, M.H. Morais, T. Mota and A.C. Ramos, Separation of color pigments of chili powder on narrow-bore HPLC columns. A comparison. J. Liq. Chrom. Rel. Technol. 24 (2001) 425 133. 

A82846B [24] and LY307599 [25] were developed as chiral selectors for CE LY333328 [26] and A35512B [27] were applied as chiral mobile phase additives in narrow-bore HPLC. 

Sharp, V.S. and Risley, D.S., Evaluation of the macrocyclic antibiotic LY333328 as a chiral selector when used as a mobile phase additive in narrow bore HPLC, Chirality, 11,75, 1999. 

Microsequencers permit sequence analysis on minute amounts of protein. Microsequencing can be used in conjunction with two-dimensional electrophoretic separations of proteins such as that shown in Box 3-C. The proteins in the polyacrylamide gel are electropho-retically transferred onto a porous sheet (membrane) of an inert material such as polyvinyl difluoride.249-251 After staining, a selected spot is cut out and placed into the sequencer. To avoid the problems associated with blocked N termini, the protein may be treated with proteases on the membrane and the resulting peptide fragments may then be separated on a narrow-bore HPLC column and sequenced.240... 

A reversed-phase HPLC column (typically Cl 8 or C30) is required for HPLC separations. Because the flow rate into the continuous-flow FAB-MS or LSIMS source must be <10 pl/min, either a capillary column must be used or else the flow must be split postcolumn. For narrow-bore HPLC columns operated at 200 pl/min, the split ratio would be 30 1. Isocratic or gradient separations may be used. A syringe pump is usually necessary for capillary columns, but standard HPLC pumps are sufficient for applications using narrow-bore columns. 

A reversed-phase HPLC Cl8 or C30 narrow-bore column is typically used for LC/MS with APCI. Details about chromatography columns used for carotenoids are contained in unit F2.3. For most APCI systems, the optimum flow rate into a mass spectrometer or tandem mass spectrometer equipped with APCI, as controlled by a syringe pump or HPLC pump, is usually between 100 and 300 pl/min, which is ideal for narrow-bore HPLC columns. Larger diameter columns should be used with a flow splitter postcolumn to reduce the solvent flow into the mass spectrometer. For example, if a 4.6 mm i.d. column was used at a flow rate of 1.0 ml/min, then the flow must be split postcolumn 5 1 so that only 200 pl/min enters the mass spectrometer. 

Food analysts have been somewhat reluctant to convert to narrow-bore HPLC. However, several vitamin methods utilize 3.2-mm-ID columns, which in a properly designed system give a twofold increase in sensitivity over 4.6-mm-ID columns. 

Croubles, S. Baeyens, W. Van Peteghem, C. Evaluation of a narrow-bore HPLC column for trace level analysis of tetracyclines-a comparison with a conventional column. Biomed.Chromatogr., 1995, 9, 251-253 [simultaneous chlortetracycline, demeclocycline, oxytetracycline]... 

These developments have been fuelled in part by the apparently unrelenting increase in microcomputing power, bringing with it improved control and data acquisition and processing capabilities and partly by the improved technologies for the preparation of chromatographic media and packings in GC and LC, for example, chiral stationary phases, bonded phase capillary GC and narrow bore HPLC. 

Analytical and narrow-bore HPLC columns are most commonly used for routine analysis, which require the highest possible robustness. Capillary- and nano-LC columns find application in various fields of biotechnology research, mainly for sample limited analysis of peptides and proteins [30-32]. 

Several useful articles and reviews on HPLC of peptides can be found in Refs. 38, 235, and 236, with Ref 237 representing a useful resource book in this area. For an extensive source of information on the early development of HPLC of peptides, the reader is directed to Ref 238. A comprehensive practical overview on this topic is supplied by Ref 239 the tatter publication also supplied much useful information on preparative approaches to HPLC purification, as well as an overview of micro- and narrow-bore HPLC of peptides. An excellent and current publication dealing with high-performance analysis of biomolecules [240] also offers a sound introduction to capillary electrophoresis (CE), an important complementary technique to conventional HPLC. 

After extraction into hexane, a solid-phase extraction, using silica and nonpolar eluents, or sometimes reversed-phase extraction with polar solvents, is common in many assays. Some research groups used a semipreparative HPLC method (silica column and acetonitrile [62,67,68] or di-isopropylether [89] in hexane) with UV detection for cleanup. Blanco-Gomis et al. (60,61), introducing narrow-bore HPLC or capillary liquid chromatography for small-sample analysis of vitamins, were able to get appropriate results without solid-phase cleanup by reextracting the hexane layer with methanol water 9 1 to remove interfering lipids, as described elsewhere (24,88,108). 

EM Kirk, AF FeU. Analysis of supplemented vitamin K,(20) in serum microsamples hy sohd-phase extraction and narrow-bore HPLC with multichannel ultraviolet detection. Clin Chem 35(7) 1288-1292, 1989. 

Seven macrocyclic antibiotics have been evaluated as chiral selectors for the enantiomeric separation of dansyl amino acids using narrow-bore HPLC (46). The dansyl amino acids are listed in Table 1.6. The antibiotics used were Vancomycin (47), A82846B,... 

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