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Why the proteins needed to be in gas phase for mass sphectrometry |
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Answer» Harge reduction electrospray mass spectrometry (CREMS) reduces the charge states of electrospray-generated ions, which concentrates the ions from a protein into FEWER peaks spread over a larger m/z range, thereby increasing peak separation and decreasing spectral congestion. An optimized design for a CREMS source is described that provides an order-of-magnitude increase in sensitivity compared to previous designs and provides control over the extent of charge reduction. Either a corona discharge or an α-particle source was employed to generateanions that ABSTRACT protons from electrosprayed protein cations. These desired ion/ion proton TRANSFER reactions predominated, but some oxidation and ion-attachment reactions also occurred, leading to new peaks or mass-shifted broader peaks while decreasing signal intensity. The species producing these DELETERIOUS side-reactions were identified, and conditions were FOUND that prevented their formation. Spectrometer |
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