A Fully Integrated Monolithic Microchip Electrospray Device for Mass Spectrometry
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- 作者：Gary A. Schultz ; Thomas N. Corso ; Simon J. Prosser ; and Sheng Zhang
- 刊名：Analytical Chemistry
- 出版年：2000
- 出版时间：September 1, 2000
- 年：2000
- 卷：72
- 期：17
- 页码：4058 - 4063
- 全文大小：205K
- 年卷期：v.72,no.17(September 1, 2000)
- ISSN：1520-6882
文摘
A novel microfabricated nozzle has been developed for theelectrospray of liquids from microfluidic devices foranalysis by mass spectrometry. The electrospray devicewas fabricated from a monolithic silicon substrate usingdeep reactive ion etching and other standard semiconductor techniques to etch nozzles from the planar surface ofa silicon wafer. A channel extends through the wafer fromthe tip of the nozzle to a reservoir etched into the oppositeplanar surface of the wafer. Nozzle diameters as small as15 
m have been fabricated using this method. Themicrofabricated electrospray device provides a reproducible, controllable, and robust means of producing nanoelectrospray of a liquid sample. The electrospray devicewas interfaced to an atmospheric pressure ionization time-of-flight mass spectrometer using continuous infusion oftest compounds at low nanoliter-per-minute flow rates.Nozzle-to-nozzle signal intensity reproducibility using 10nozzles was demonstrated to be 12% with single-nozzlesignal stability routinely less than 4% relative standarddeviation (RSD). Solvent compositions have been electrosprayed ranging from 100% organic to 100% aqueous.The signal-to-noise ratio from the infusion of a 10 nMcytochrome c solution in 100% water at 100 nL/min was450:1. Microchip electrospray nozzles were comparedwith pulled capillaries for overall sensitivity and signalstability for small and large molecules. The microchipelectrospray nozzles showed a 1.5-3-times increase insensitivity compared with that from a pulled capillary, andsignal stability with the microchip was 2-4% RSD compared with 4-10% with a pulled capillary. Electrospraydevice lifetimes achieved thus far have exceeded 8 h ofcontinuous operation and should be sufficient for typicalmicrofluidic applications. The total volume of the electrospray device is less than 25 pL, making it suitable forcombination with microfluidic separation devices.
m have been fabricated using this method. Themicrofabricated electrospray device provides a reproducible, controllable, and robust means of producing nanoelectrospray of a liquid sample. The electrospray devicewas interfaced to an atmospheric pressure ionization time-of-flight mass spectrometer using continuous infusion oftest compounds at low nanoliter-per-minute flow rates.Nozzle-to-nozzle signal intensity reproducibility using 10nozzles was demonstrated to be 12% with single-nozzlesignal stability routinely less than 4% relative standarddeviation (RSD). Solvent compositions have been electrosprayed ranging from 100% organic to 100% aqueous.The signal-to-noise ratio from the infusion of a 10 nMcytochrome c solution in 100% water at 100 nL/min was450:1. Microchip electrospray nozzles were comparedwith pulled capillaries for overall sensitivity and signalstability for small and large molecules. The microchipelectrospray nozzles showed a 1.5-3-times increase insensitivity compared with that from a pulled capillary, andsignal stability with the microchip was 2-4% RSD compared with 4-10% with a pulled capillary. Electrospraydevice lifetimes achieved thus far have exceeded 8 h ofcontinuous operation and should be sufficient for typicalmicrofluidic applications. The total volume of the electrospray device is less than 25 pL, making it suitable forcombination with microfluidic separation devices.