Microchip technology in mass spectrometry

Sikanen, Tiina; Franssila, Sami; Kauppila, Tiina J.; Kostiainen, Risto; Kotiaho, Tapio; Ketola, Raimo A.

doi:10.1002/mas.20238

Cited by 82 publications

(95 citation statements)

References 271 publications

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“…UV absorbance detection, commonly applied in classical CE [4], is challenging in chip-based microfluidics [5,6] mainly due to the limited optical path length. Various detection methods have been implemented in MCE, the most common are electrochemical [7][8][9], mass spectrometric [10][11][12] and fluorescence-based [13,14] techniques. Fluorescence is the most successful method due to its relative ease of implementation and the unsurpassed sensitivity even enabling detection at single molecule level.…”

Section: Introductionmentioning

confidence: 99%

Label‐free analysis in chip electrophoresis applying deep UV fluorescence lifetime detection

et al. 2011

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Herein we introduce deep UV fluorescence lifetime detection in microfluidics applied for label-free detection and identification of various aromatic analytes in chip electrophoresis. For this purpose, a frequency quadrupled Nd:YAG (neodymium-doped yttrium aluminum garnet) picosecond laser at 266 nm was incorporated into an inverse fluorescence microscope setup with time-correlated single photon counting detection. This allowed recording of photon timing with sub-nanosecond precision. Thereby fluorescence decay curves are gathered on-the-fly and average lifetimes can be determined for each substance in the electropherogram. The aromatic compounds serotonin, propranolol, 3-phenoxy-1,2-propanediol and tryptophan were electrophoretically separated using a fused-silica microchip. Average lifetimes were independently determined for each compound via bi-exponential tail fitting. Time-correlated single photon counting also allows the discrimination of background fluorescence in the time domain. This results in improved signal-to-noise-ratios as demonstrated for the above model analytes. Microchip electrophoretic separations with fluorescence lifetime detection were also performed with a protein mixture containing lysozyme, trypsinogen and chymotrypsinogen emphasizing the potential for biopolymer analysis.

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Section: Introductionmentioning

confidence: 99%

Label‐free analysis in chip electrophoresis applying deep UV fluorescence lifetime detection

et al. 2011

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“…A clear trend in on-chip integrated electrospray emitters was observed. In electrospray ionisation (ESI), reducing emitter aperture size is actively being pursued (Arscott and Troadec 2005;Mery et al 2008;Gibson et al 2009;Sikanen et al 2010), because of smaller droplets being generated. The enhanced ionisation efficiency obtained is of use to proteomics (Valaskovic et al 1995) and metabolomics.…”

Section: Introductionmentioning

confidence: 99%

Nano-slit electrospray emitters fabricated by a micro- to nanofluidic via technology

Dijkstra

Berenschot

Boer

et al. 2012

Microfluid Nanofluid

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This article presents nano-slit electrospray emitters fabricated by a micro-to nanofluidic via technology. The main advantage of the technology is the ability to position freely suspended nanochannels anywhere on a microfluidic chip, where leak-tight delivery of fluid from a fluid reservoir can be established through long microchannels. The technology has proven to be useful in creating electrospray emitters coupled to freely suspended microchannels. It was observed that filling of nanochannels through via connections with integrated microchannels occurs not only due to bulk capillary action. These observations lead to a redesign of the electrospray chips. Repeatable electrospray IV-curves could be obtained from fabricated nano-slit electrospray emitters. Moreover, integration of on-chip microfluidic components is one of the possibilities of the fluidic via technology presented.

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“…Additional features such as pneumatic nebulizers have been incorporated to enhance emission [44,54,55]. Reviews of lab-on-a-chip nanoelectrospray sources can be found in [56][57][58][59].…”

Section: Introductionmentioning

confidence: 99%

MEMS-Based Nanospray-Ionization Mass Spectrometer

Wright¹,

Syms

Moseley³

et al. 2010

J. Microelectromech. Syst.

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An electrospray ionisation mass spectrometer (ESI-MS) whose main components are all fabricated using silicon microelectromechanical systems (MEMS) techniques is demonstrated for the first time. The ion source consists of a microengineered alignment bench containing a V-groove mounting for a nanospray capillary, an ion extraction electrode, and a pneumatic nebuliser. The vacuum interface consists of two plates, each carrying a 50 µm diameter capillary, that are selectively etched and bonded together to provide a differentially pumped internal cavity. The quadrupole filter consists of a microfabricated frame that provides mountings for stainless steel rods measuring 650 µm in diameter and 30 mm in length. Two different quadrupoles are compared: a firstgeneration bonded silicon device, and a second-generation silicon-on-glass device with a Brubaker prefilter. Differential pumping of a MEMS component is demonstrated for the first time, atmospheric pressure ionisation and ion transfer into vacuum are characterised, ESI-MS operation is demonstrated and spectra are presented for a variety of compounds. KEYWORDS:Mass spectrometry, Electrospray, Quadrupole filter, MEMS IntroductionOver 25 years have passed since an electrospray ionisation (ESI) source was first coupled to a quadrupole mass spectrometer (MS) by Yamashita and Fenn [1]. Since then, ESI-MS has become a workhorse of analytical chemistry, allowing analytes to be ionised at atmospheric pressure with little fragmentation and passed into a vacuum system for analysis.Conventional ESI sources employ spray tips with an internal diameter (ID) of ≈100 µm[2]. In order to establish a Taylor cone and maintain stable emission of charged droplets, minimum flow rates of 0.5 -5 µL min -1 and voltages of 2.5 -4 kV are used. However, it has been convincingly demonstrated that high sensitivity and stable emission can be achieved at much lower flow rates and voltages using spray tips with IDs of ≈ 5 µm, and silica nanospray capillaries with a range of coatings have become widely available [3][4][5][6][7][8].Unfortunately, while these are inexpensive, operator expertise and costly positioning apparatus are often required for stable and reproducible performance.Electrosprayed ions are passed into a low-pressure chamber via a vacuum interface. The simplest interface is a single orifice or capillary that allows gas and entrained ions to pass directly into the vacuum chamber. Clearly, the orifice must be small enough or the pumps large enough to ensure that the pressure is consistent with mass analysis. However, the susceptibility of very small orifices to clogging and the inconvenience of large pumps led to this approach being abandoned. Modern instruments employ one or more stages of 4 differential pumping. Larger orifices can be tolerated since only a fraction of the flow is transmitted to the vacuum chamber, while the majority of the gas load can be pumped away at higher pressure using more modest pumps.The effective transfer of ions and molecules from atmospheric pressu...

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Microchip technology in mass spectrometry

Cited by 82 publications

References 271 publications

Label‐free analysis in chip electrophoresis applying deep UV fluorescence lifetime detection

Label‐free analysis in chip electrophoresis applying deep UV fluorescence lifetime detection

Nano-slit electrospray emitters fabricated by a micro- to nanofluidic via technology

MEMS-Based Nanospray-Ionization Mass Spectrometer

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