Michael X. Li

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A polybrene capillary coating in capillary electrophoresis (CE) has been used for rapid analysis of hemoglobin variant digests. The use of the polybrene capillary coating has allowed sufficient separation to resolve the large number of digest products formed upon tryptic digestion of the whole protein, so that prior separation of the hemoglobin alpha and(More)
The interface of high-resolution capillary separation methods to time-of-flight mass spectrometry (TOF-MS) has generated considerable interest since TOF can provide the rapid and sensitive detection required by high resolution separations. In recent years, our laboratory has developed a variety of high-resolution capillary separation methods interfaced to(More)
Pressurized capillary electrochromatography (pCEC) has been coupled to an ion trap storage/reflectron time-of-flight mass spectrometer for the analysis of peptide mixtures and protein digests. Taking advantage of the electroosmotic flow, high separation efficiency has been achieved in pCEC due to a relatively flat flow profile and the use of smaller packing(More)
A three-dimensional (3-D) contour map format has been developed to display the large amount of data continuously collected throughout an on-line capillary separation using an ion trap storage/reflectron time-of-flight detector (IT/reTOF). The resulting data are displayed on a single computer screen with a mass-to-charge ratio value-elution time-intensity(More)
As small animal models of disease become more widely used, there is increasing importance and potential for characterizing their metabolomes. However, as the animal becomes smaller, the amounts of biofluids such as urine and cerebral spinal fluid available for metabolomic studies are more limited. Further, in multi-platform systems biology when the same(More)
An ion trap storage (IT)/reflectron time-of-flight mass spectrometer (reTOFMS) has been coupled to capillary electrophoresis (CE) via a sheathless microelectrospray ionization method. This hybrid mass spectrometer has proved to be a rapid and sensitive detector for CE, where mass spectra could be acquired at a speed sufficient to maintain the(More)
Capillary electrophoresis/electrospray ionization using an ion trap storage/reflectron time-of-flight mass spectrometer detector (CE/ESI-IT/reTOF) is used to provide a rapid and sensitive method for analyzing structural variants in the hemoglobin (Hb) â-chain. The Hb αand â-chains are separated and the â-chain is digested by trypsin. The digest is analyzed(More)
Capillary electrophoresis/electrospray ionization using an ion trap storage/reflectron time-of-flight mass spectrometer detector (CE/ESI-IT/reTOF) is used to provide a rapid and sensitive method for analyzing structural variants in the hemoglobin (Hb) beta-chain. The Hb alpha- and beta-chains are separated and the beta-chain is digested by trypsin. The(More)
In this work, a novel open-tubular column (OTC) capillary electrochromatography (CEC) system has been coupled to an on-line ion trap storage/reflectron time-of-flight mass spectrometer for ultrafast peptide mixture analysis. Reversed-phase OTCs prepared by the sol-gel process were coated with an amine, which greatly enhanced the electroosmotic flow in an(More)