Micro-column

Bystryakov et al. [36] described a double detection method to determine aliphatic thiols by HPLC. A solution of 0.1-1 mg/mL of such compounds in the mobile phase was analyzed by HPLC using a of Nucleosil C18 micro-column (5 pm 6.2 cm x 2 mm)... 

Hashimoto, Y., Tokura, K., Ozaki, K., Strachan, W.M.J. (1982) A comparison of water solubilities by the flask and micro-column methods. Chemosphere 11(10), 991-1001. 

Svensson, L.A. et ah. Vancomycin-based chiral stationary phases for micro-column liquid chromatography. Chirality, 11, 121, 1999. 

Al-Dirbashi O, Wada M, Kuroda N, Takahashi M, Nakashima K. 2000. Achiral and chiral quantification of methamphet-amine and amphetamine in human urine by semi-micro column high-performance liquid chromatography and fluorescence detection. J Forensic Sci 45(3) 708-714. 

In addition to the commercially available systems, several authors have described laboratory-built systems using commercially available components from companies such as Upchurch Scientific (Oak Harbor, WA). One of the first reported laboratory-built micro-bore HPLC systems was described by Simpson and Brown, which was a simple adaptation of a standard HPLC system to accept micro-bore columns built from guard columns. A complete system has been described based on dual microdialysis syringe pumps (CMA Microdialysis, Chelmsford, M A) or dual syringe pumps (Harvard Apparatus, Inc., Holliston, MA), a microinjection port, and a micro-column the latter components being obtained from Upchurch scientific (Figure 3.5). This system was coupled with a laser-induced fluorescence (LIF) detector and used to measure neuropeptides in sub-microliter samples. A further modification of this system was built to perform immunoaffinity isolations of biomedically important analytes from clinical samples. ... 

Wada, M., Nakamura, S., Tomita, M., Nakashima, M. N., and Nakashima, K., Determination of MDMA and MDA in rat urine by semi-micro column HPLC-fluorescence detection with DBD-F and their monitoring after MDMA administration to rat. Luminescence 20(3), 210-215, 2005. 

Micro-HPLC operation sets special demands on the gradient instrumentation. As the internal column diameter, d, decreases, lower flow rates should be used at comparable mean linear mobile phase velocities, u = 0.2-0.3 mm/s. At a constant operating pressure, the flow rate decreases proportionally to the second power of the column inner diameter, so that narrow-bore LC columns with 1mm i.d. require flow rates in the range of 30-100pL/min, micro-columns with i.d. 0.3-0.5mm, flow rates in between 1 and lOpL/min, and columns with 0.075-0.1 mm i.d. flow rates in the range of hundreds nL/min. Special miniaturized pump systems are required to deliver accurately mobile phase at very low flow rates in isocratic LC. 

Broccoli Extraction with boiling MeOH (70%) for group separation of neutral, acid and basic AA on micro-columns Spherisorb S3 ODS2 (150x4.6mm) Phosphate buffer (0.2% NaNOjj/ACN OPA/2- mercaptoethanol UV-Vis (340 nm) [242,247]... 

Use of HP micro-column LC to identify and to assess quality of drugs of the cortisone group. (165)... 

The fractality index a obtained from analysis of SANS curves correlates with the adsorption capacity of carbon materials for unconjugated bilirubin adsorbed from HSA solution in micro-column single-pass experiments (Table 29.2) [10]. 

In Table 29.3 the results of adsorption of pro-inflammatory cytokines by four types of hemosorbents in micro-column single-pass experiments are presented. 

Fractionally distd through a Widmer column as a mobile liquid and redistilled with a Claisen flask or through a semi-micro column (Gould, Holzman and Neiman AC 20 361 1948. NB It has a strong characteristic disagreeable odour dectectable at low concentrations and causes headaches on prolonged exposure. [IR Cope and Estes JACS 72 1128 1950 UV Cope and Baumgardner JACS 78 2812 7956]. 

Interfacing HPLC or HPCE (capillary electrophoresis) to mass spectrometry is technically more complex than. with a GC because these techniques use a solvent that is often aqueous (water is a poison to mass spectrometers). The use of microcolumns in HPLC is desirable for coupling to MS because micro-columns operate at very low flow rates. They are also compatible with different ionisation techniques for the analysis of high molecular-weight species. 

Cronch, E. A. C., and I. G. Swainbank The Separation of Fission Products on Ion-Exchange Micro-Columns. In Proceedings of the International Symposium on Microchemistry, Birmingham, 1958. Oxford Pergamon Press 1960. 

Witkiewicz, Z., Suprynowicz, Z., Wojcik, J., and Dabrowski, R., Separation of the isomers of some disubstituted benzenes on liquid crystalline stationary phases in small-bore packed micro-columns, J. Chromatogr., 152, 323, 1978. 

Welch KJ, Hoffman NE. 1993. Analysis of polychlorinated biphenyls, dibenxodioxins and dibenzofurans by online coupled micro-column HPLC capillary GC-MS. Journal of Liquid Chromatography 16 307-313. 

Early in the development of capillary electrophoresis, it was noted that the successful detection of separated sample components present within the narrow confines of these capillary tubes posed a major challenge (2)- In response to this challenge, much research has been directed toward the development of sensitive and selective detectors for capillary electrophoresis. CE detector technology has been largely borrowed from the field of high-performance liquid chromatography (HPLC), especially from micro-column HPLC. 

High Inlet Pressure Micro Column System for Use in Gas Chromatography, M. N. 

Cardenas, M.S., Van Der Heeft, E. and de Jong, A.P.J.M. (1997) On-line derivatization of peptides for improved sequence analysis by micro-column liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Rapid Commun. Mass Spectrom., 11 (12), 1271-8. 

---