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Ready‐made matrix‐assisted laser desorption/ionization target plates coated with thin matrix layer for automated sample deposition in high‐density array format
Author(s) -
Miliotis Tasso,
Kjellström Sven,
Nilsson Johan,
Laurell Thomas,
Edholm LarsErik,
MarkoVarga György
Publication year - 2001
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.542
Subject(s) - chemistry , nitrocellulose , analytical chemistry (journal) , analyte , thin film , matrix (chemical analysis) , sample preparation , chromatography , materials science , nanotechnology , biochemistry , membrane
The methodology for ready‐made matrix‐assisted laser desorption/ionization (MALDI) target plates covered with an optimized thin layer consisting of matrix and nitrocellulose has been developed. Piezoelectric microdispensing enabled sample depositions in a high‐density array format of 2000 sample depositions on a conventionally sized target plate (45 × 47 mm). The sample depositions were made reproducibly in a fully automated mode by using an in‐house developed computer‐controlled piezoelectric flow‐through microdispenser. Additionally, the piezoelectric technique facilitated significant analyte enrichment that increased the detection sensitivity. The MS signal was obtained rapidly, generally within ten laser pulses. An airbrush device was used to generate a fine spray of matrix and nitrocellulose dissolved in acetone. The acetone evaporated instantly when reaching the target plate leaving the entire surface with a thin and uniform matrix/nitrocellulose coating consisting of very small crystals of matrix embedded in the nitrocellulose. These crystals acted as a seed‐layer on subsequent analyte depositions, rendering homogeneous sample spots when using α‐cyano‐4‐hydroxycinnamic acid (CHCA) as matrix. The relative standard deviation of the signal intensity between spots was (20–30)% (n = 30). The detection sensitivity was improved by restricting the sample spot diameter to 300 µm. The spot size was affected by the deposition rate and the evaporation rate of the dispensed sample volume. Mass spectra of a 25‐amol peptide mixture deposition were successfully recorded. Copyright © 2001 John Wiley & Sons, Ltd.