Fully Microfabricated and Integrated SU-8-Based Capillary Electrophoresis-Electrospray Ionization Microchips for Mass Spectrometry (original) (raw)
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International Journal of Mass Spectrometry, 2012
The applications of rapid screening benzodiazepines from urine and determining synthetic reaction products and kinetics semi-quantitatively using a microfabricated rotating multitip electrospray ionization (ESI) platform for mass spectrometry (MS) is presented. The ESI tips are based on lidless micropillar array ESI (PESI) sources where the transfer of liquid is based on capillary forces without external pumping. A single silicon platform contains 60 separate PESI tips which can be individually used by rotating the whole platform by six degrees each time from tip to tip using a computer control. The rotating multitip PESI platform with an ion trap mass spectrometer was successfully demonstrated in rapid identification and monitoring of intermediates and final products in chemical synthesis within 10 min. The system was also applied to high-throughput screening of benzodiazepines from urine samples. Urine samples were extracted with solid-phase extraction (SPE) using C 18 phase ZipTip TM pipettes, enabling the use as small sample volumes as 50 L of the urine sample. Therefore the whole sample treatment and the analysis with the rotating multitip PESI-MS took only 5 min per sample.
Analytical Chemistry, 1999
The development of a system capable of the speed required for on-line capillary electrophoresis-tandem mass spectrometry (CE-MS/MS) of tryptic digests is described. The ion trap storage/reflectron time-of-flight (IT/reTOF) mass spectrometer is used as a nonscanning detector for rapid CE separation, where the peptides are ionized on-line using electrospray ionization (ESI). The ESI produced ions are stored in the ion trap and dc pulse injected into the reTOF-MS at a rate sufficient to maintain the separation achieved by CE. Using methodology generated by software and hardware developed in our lab, we can produce SWIFT (Stored Waveform Inverse Fourier Transform) ion isolation and TICKLE activation/fragmentation voltage waveforms to generate MS/MS at a rate as high as 10 Hz so that the MS/MS spectra can be optimized on even a 1-2 s eluting peak. In CE separations performed on tryptic digests of dogfish myelin basic protein (MBP) where eluting peaks 4-8 s wide are observed, it is demonstrated that an acquisition rate of 4 Hz provides >20 spectra/peak and is more than sufficient to provide optimized MS/MS spectra of each of the eluting peaks in the electropherogram.
Sheathless capillary electrophoresis-mass spectrometry using a pulsed electrospray ionization source
ELECTROPHORESIS, 2006
A sheathless interface has been developed for coupling CE with electrospray IT mass spectrometer. This interface utilized a pulsed ESI source. The use of a pulsed electrospray source allows the use of a sprayer with larger orifice, and thus alleviates the problem of column clogging during conductive coating and CE analysis. A pulsed ESI source operated at 20 Hz and 20% duty cycle was found to produce the optimal signals. For better signals, the maximum ion injection time in the IT mass spectrometer has to be set to a value close to the actual spraying time (10 ms). Using a sprayer with 50 mm od, more stable and enhanced signals were obtained in comparison with continuous CE-ESI-MS under the same flow rate (150 nL/min). The utility of this design is demonstrated with the analysis of synthetic drugs by CE-MS.
Capillary zone electrophoresis - mass spectrometry using an electrospray ionization interface
Analytical Chemistry, 1988
Mixtures of peptides have been analyzed by capillary zone electrophoresis in conjunction with mass spectrometry (MS) using an on-line coaxial continuous-flow fast atom bombardment interface. MS and MS-MS spectra have been acquired in electrophoretic real time from femtomole levels of the peptides, while maintaining separation efficiencies in excess of 100 000 theoretical plates.
Journal of The American Society for Mass Spectrometry, 2012
A novel electrospray nebulizer has been designed, which includes an additional nebulization gas capillary inside the liquid capillary. This design offers significantly enhanced ionization efficiency compared with the classic nebulizer design and leads to improved sensitivity (by three to 10 times) and decreases the detection limit, on an average 10 times. We see these results as the first step in the design of ESI nebulizers offering improved sensitivity and higher robustness. Possible future developments would include optimization of the dimensions of the capillaries as well as testing the nebulizer for other matrices and analytes.
Analytical Chemistry, 2003
Although several designs have been advanced for coupling sample enrichment devices to a sheathless electrospray ionization-mass spectrometry (MS) interface on a capillary electrophoresis (CE) column, most of these approaches suffer from difficulties in fabrication, and the CE separation efficiency is degraded as a result of the presence of coupling sleeves. We have developed a design that offers significant improvements in terms of ease of fabrication, durability, and maintenance of the integrity of the CEseparated analyte zones. Capillaries with different inside and outside diameters were evaluated to optimize the performance of the CE-MS system, resulting in a mass limit of detection of 500 amol for tandem MS analysis of a standard peptide using a 20-µm-i.d. capillary. The improved design incorporates an efficient method to preconcentrate a sample directly within the CE capillary followed by its electrophoretic separation and detection using a true zero dead-volume sheathless CE-MS interface. Testing of this novel CE-MS system showed its ability to characterize proteomic samples such as protein digests, in-gel-digested proteins, and hydrophobic peptides as well as to quantitate ICAT-labeled peptides.
Review Capillary electrophoresis-mass spectrometry
1995
As an on-line separation method, capillary electrophoresis (CE)-mass spectrometry (MS) distinguishes analytes by both their differences in electrophoretic mobilities and structural information. CE-MS combines the advantages of CE and MS so that information on both high separation efficiency and molecular masses and/or fragmentation can be obtained in one analysis. During the past few years CE-MS has undergone significant development both in instrumentation and application. Several ionization methods have been used for CE-MS. These include electrospray ionization, ion spray or pneumatically assisted electrospray ionization, and continuous-flow fast atom bombardment. The direct coupling of CE to desorption MS has not yet been reported, although publications have appeared on the off-line coupling of CE with matrix-assisted laser resorption ionization and Z52Cf plasma desorption MS using fraction collection. Numerous new applications of CE-MS have been published in the areas of biologic...