Capillary chip-based

Effenhauser, CS Bruin, GJM Paulus, A, Integrated Chip-Based Capillary Electrophoresis, Electrophoresis 18, 2203, 1997. 

Fang, Q., Wang, F.-R., Wang, S.-L., Liu, S.-S., Xu, S.-K., and Fang, Z.-L., Sequential injection sample introduction microfluidic-chip based capillary electrophoresis system, Anal. Chim. Acta, 390, 27, 1999. 

Litbom, E., Emmer, A., and Roeraade, J., Chip-based nanovials for tryptic digest and capillary electrophoresis, Anal. Chim. Acta, 401, 11, 1999. 

The sample throughput of nanoESI is limited by the comparatively time-consuming procedure of manual capillary loading. A chip-based nanoESI sprayer on an etched silicon wafer allows for the automated loading of the sprayer array by a pipetting robot (Fig. 11.7). The chip provides a 10 x 10 array of nanoESI... 

Fig. 11.7. Illustration of the chip-based Advion nanoESI system. The pictures stepwise zoom in from the pipetting unit to the spray capillary on the silicon chip. By courtesy of G. Schultz, Advion BioSciences, Ithaca, NY.

Deng, Y., Zhang, H., and Henion, J. (2001). Chip-based quantitative capillary electrophoresis/mass spectrometry determination of drugs in human plasma. Anal. Chem. 73, 1432—1439. 

Very low flow electrospray is called nanoelectrospray [26] where the samples are infused into the mass spectrometer at the nanoliter flow rate range. The infusion of a few microliters will result in a stable signal for more then 30 min, using pulled capillaries or chip-based emitters [27]. With infusion, signal averaging allows to improve the limit of detection in tandem mass spectrometry. Nanoelectrospray is particularly important in combination with nanoflow liquid chromatography or chip-based infusion for the analysis of peptides and proteins. 

Fig. 5.9 Design of the chip-based enzyme ESI-MS assay. MS instrument Ion-trap mass spectrometer (LCQ Deca, Thermo Electron). I Sample components/inhibitors injected by flow injection or eluting from capillary HPLC column. E Infusion pump delivering the enzyme cathepsin B. S infusion pump delivering the substrate Z-FR-AMC. Micro-chip design Vrije Universiteit Amsterdam. Micro-chip production Micronit Microfluidics BV (Enschede, The Netherlands).

Wang, J., M. Pumera, and G. Collins. A chip-based capillary electrophoresis-contactless conductivity microsystem for fast measurements of low-explosive ionic components. Analyst 127, 719-723 (2002). 

Although this section provides a brief description of most commonly nsed detectors for HPLC, most of the focus is on a few detection modes. Optical absorbance detectors remain the most widely nsed for HPLC, and are discnssed in some detail. We also focns on flnorescence, condnctivity, and electrochemical detection, as these methods were not widely nsed for HPLC in the past, bnt are especially well suited to micro- and nano-flow instrnments becanse of their high sensitivity in small sample volumes. Mass spectrometry has also come into wide and rontine nse in the last decade, but as it is the subject of another chapter, it will not be fnrther discnssed here. Miniaturization has been particularly important for capillary and chip-based electrophoresis, which often employs sub-nanoliter detection volnmes [36,37]. 

Vrouwe, E. X. Gysler, J. Tjaden, U. R. van der Grccf, J. 2000. Chip-based capillary electrophoresis with an electrodeless nanospray interface. Rapid Commun. Mass Spectrom., 14,1682-1688. 

Effenhauser, C.S., Bruin, G.J.M., Paulus, A., Integrated chip-based capillary electrophoresis. Electrophoresis 1997, 18, 2203-2213. 

Fang, Q., Xu, G.-M., Fang, Z.-L., High throughput continuous sample introduction interfacing for microfluidic chip-based capillary electrophoresis systems. Micro Total Analysis Systems, Proceedings 5th XTAS Symposium, Monterey, CA, Oct. 21-25, 2001, 373-374. 

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