Chromatographic system, automated 2-dimensional

Isobe, T., Uchida, K., Taoka, M., Shinkai, F., Manabe, T., Okuyama, T. (1991). Automated two-dimensional liquid chromatographic system for mapping proteins in highly complex mixtures. J. Chromatogr. 588, 115-123. 

K. Matsuoka, M. Taoka, T. Isobe, T. Okuyama and Y. Kato, Automated high-resolution two-dimensional hquid chromatographic system for the rapid and sensitive separation of complex peptide mixtures ,/. Chromatogr. 515 313-320 (1990). 

A fully automated two-dimensional (2D) chromatographic system was developed by Kilz et al. [91-93]. It consists of two chromatographs, one which separates by chemical composition or functionality and an SEC instrument for subsequent separation by size. Via a storage loop system, fractions from the first... 

The SEC analysis of components separated according to the chemical composition under critical conditions maybe carried out after transferring of effluent from column under critical conditions into a SEC column. This procedure requires additional sample valve with loading loops plus the adjustment of flow velocity and column dimensions [106]. The procedure is known as two-dimensional separation (for references see [22,25]). A fully automated chromatographic system for two-dimensional separation was developed by Kilz et al. [ 106,177] and is commercially available [178]. On the other hand, a reinjection of analyzed fraction from column working at critical conditions into the additional SEC column is not necessary, when two different systems under critical conditions are found, i.e. one for each components of copolymer (using two different columns or two different eluents). Corresponding complementary LCCC systems may be selected from Table 1-3. In this case, parts of copolymer, which are not under CEEC, should be eluted in SEC modus. The distribution of molar mass of both components of copolymers may be then measured directly under critical conditions, as have been demonstrated in [47,67,78,80]. If necessary, LCCC maybe scaled up to preparative quantities [71]. 

Automation has been inttoduced into the analysis of peptides and proteins, especially in the study of proteomes. Exttacts of proteins from cells are separated using two dimensional gel techniques, usually a chromatographic and an electrophoretic separation. Protein spots are identified and cut out. After tryptic digestion the mixture of peptide fragments is analysed by mass spectrometry, usually either by MALDI-ToF or by nanoelectrospray analysis. The pattern of masses obtained from the peptides is then compared with a database showing the patterns obtained from many proteins. Matches are con ared and identifications are proposed. Several manufacturers offer complete systems which carry out this analysis automatically. 

Two-dimensional (2D) separation systems are of interest because of their increased peak capacity over one-dimensional separations. Microfabricated devices (microchips) are potentially useful for multidimensional separations because high-efficiency separations can be achieved and small sample volumes can be manipulated with minimal dead volumes between interconnecting channels. Various techniques may be adopted for the fabrication of chromatographic columns in microchips for p-CEC following integration with other orthogonal separation methods as well as sample pretreatment proaches for rapid, automated analysis of more complicated biosamples with possible coupling to mass spectrometric detection. 

Fig. 2. (a) General experimental design of a 2-dimensional chromatograph, (b) Completely automated 2D instrument comprising of gradient pump (1st dimension, left), 2D transfer valve (on gradient pump) and GPC system for 2nd dimension. 

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