title: Self-aliquoting microarray plates for accurate quantitative matrix-assisted laser desorption/ionization mass spectrometry.
abstract: Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a fast analysis tool employed for the detection of a broad range of analytes. However, MALDI-MS has a reputation of not being suitable for quantitative analysis. Inhomogeneous analyte/matrix co-crystallization, spot-to-spot inhomogeneity, as well as a typically low number of replicates are the main contributing factors. Here, we present a novel MALDI sample target for quantitative MALDI-MS applications, which addresses the limitations mentioned above. The platform is based on the recently developed microarray for mass spectrometry (MAMS) technology and contains parallel lanes of hydrophilic reservoirs. Samples are not pipetted manually but deposited by dragging one or several sample droplets with a metal sliding device along these lanes. Sample is rapidly and automatically aliquoted into the sample spots due to the interplay of hydrophilic/hydrophobic interactions. With a few microliters of sample, it is possible to aliquot up to 40 replicates within seconds, each aliquot containing just 10 nL. The analyte droplet dries immediately and homogeneously, and consumption of the whole spot during MALDI-MS analysis is typically accomplished within few seconds. We evaluated these sample targets with respect to their suitability for use with different samples and matrices. Furthermore, we tested their application for generating calibration curves of standard peptides with α-cyano-4-hdydroxycinnamic acid as a matrix. For angiotensin II and [Glu(1)]-fibrinopeptide B we achieved coefficients of determination (r(2)) greater than 0.99 without the use of internal standards.
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zürich , Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Pabst
authors.forename: Stephan R
authors.initials: SR
authors.lastname: Fagerer
authors.forename: Rudolf
authors.initials: R
authors.lastname: Köhling
authors.forename: Simon K
authors.initials: SK
authors.lastname: Küster
authors.forename: Robert
authors.initials: R
authors.lastname: Steinhoff
authors.forename: Martin
authors.initials: M
authors.lastname: Badertscher
authors.forename: Fabian
authors.initials: F
authors.lastname: Wahl
authors.forename: Petra S
authors.initials: PS
authors.lastname: Dittrich
authors.forename: Konstantins
authors.initials: K
authors.lastname: Jefimovs
authors.forename: Renato
authors.initials: R
authors.lastname: Zenobi
mesh_terms: D000818:Animals; D002138:Calibration; D004867:Equipment Design; D010455:Peptides / Q000032:analysis / Q000378:metabolism; D040081:Protein Array Analysis / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*; D014357:Trypsin / Q000378:metabolism
chemical_list: D010455:Peptides; D014357:Trypsin