An important interface modification for capillary isoelectric focusing mass spectrometry(CIEF MS) is reported. A capillary needle with a sheath flow tube pre mounted in one device serves as both the CIEF cathodic end ...An important interface modification for capillary isoelectric focusing mass spectrometry(CIEF MS) is reported. A capillary needle with a sheath flow tube pre mounted in one device serves as both the CIEF cathodic end and the ESI interface. The needle was inserted into the cathode reservoir at the focusing stage, and then removed to the front of sampler orifice of MS at the detection stage. Therefore, the shut off of the high voltage is not necessary and a better focusing protein zone is maintained during the ESI stage. The optimization of the experimental condition has been investigated and the two dimensional image of the E. coli proteins has been obtained, which is comparable with that from a 2D gel.展开更多
A lab-made off line 2D-LC-MS system was developed for protein analysis. In case the off line 2D-LC was utilized for peptide separation, and the working conditions for strong cation exchange(SCX) chromatography and the...A lab-made off line 2D-LC-MS system was developed for protein analysis. In case the off line 2D-LC was utilized for peptide separation, and the working conditions for strong cation exchange(SCX) chromatography and the succeeding reversed phase(RP) chromatography can be individually optimized, contrasted to the on-line system. The experimental results show that the mass fractions of acetonitrile for the SCX separation can be increased form 5% as references reported up to 20% so that the separation of peptides has been substantially improved. The off line system has been applied to the analysis of proteins extracted from the cancer tissue of nude mice inoculated by a human-hepatocellular-carcinoma cell-line D20. Some extreme basic proteins(pI>10) and larger proteins(M w>200 000), which are difficult to be isolated by the traditional 2D-PAGE method, have been identified in D20 sample.展开更多
文摘An important interface modification for capillary isoelectric focusing mass spectrometry(CIEF MS) is reported. A capillary needle with a sheath flow tube pre mounted in one device serves as both the CIEF cathodic end and the ESI interface. The needle was inserted into the cathode reservoir at the focusing stage, and then removed to the front of sampler orifice of MS at the detection stage. Therefore, the shut off of the high voltage is not necessary and a better focusing protein zone is maintained during the ESI stage. The optimization of the experimental condition has been investigated and the two dimensional image of the E. coli proteins has been obtained, which is comparable with that from a 2D gel.
文摘A lab-made off line 2D-LC-MS system was developed for protein analysis. In case the off line 2D-LC was utilized for peptide separation, and the working conditions for strong cation exchange(SCX) chromatography and the succeeding reversed phase(RP) chromatography can be individually optimized, contrasted to the on-line system. The experimental results show that the mass fractions of acetonitrile for the SCX separation can be increased form 5% as references reported up to 20% so that the separation of peptides has been substantially improved. The off line system has been applied to the analysis of proteins extracted from the cancer tissue of nude mice inoculated by a human-hepatocellular-carcinoma cell-line D20. Some extreme basic proteins(pI>10) and larger proteins(M w>200 000), which are difficult to be isolated by the traditional 2D-PAGE method, have been identified in D20 sample.
