Peptides capillary electrophoretic analysis

Righetti, P. G. (2001). Capillary electrophoretic analysis of proteins and peptides of biomedical and pharmacological interest. Biopharm. Drug Dispos. 22, 337—351. 

Figure 10.3 shows the IR-LDI mass spectrum of the peptide bradykinin (Mr = 1060.2) desorbed and ionized from the PDMS cover. The bradykinin was loaded into the chip at a concentration of 2.5 mM and injected into the chip channel using a field of 150 Y cm-1 for 9 min. The spectrum is the result of 10 laser shots at 2.95 pm wavelength. The off-line capillary gel microfluidic mass spectra are obtained after electrophoretic transport through a closed chip channel. Operation with a closed channel requires that the cover be removed from the chip prior to analysis. When removing the cover, sections of the gel tended to adhere to the surface of the PDMS. With some amount of care the entire gel lane could be extracted intact from the chip and, in many cases, irradiation of the PDMS cover resulted in the best mass spectra. The base peak... 

In general, for analysis of a peptide with an unknown migration pattern, it is logical to start with an uncoated capillary at basic pH (0.05 M sodium borate buffer, pH 8.0, for example). Under these conditions, EOF will give a rapid initial separation of the sample components. Prior to the electrophoretic run, the capillary should be cleaned and conditioned. This is accomplished by rinsing the capillary in acid and base, as shown in Table 2. CE protocols often include these rinses to ensure that the capillary is prop-... 

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