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Silicon micropillar array electrospray chip for drug and biomolecule analysis
Author(s) -
Nissilä Teemu,
Sainiemi Lauri,
Sikanen Tiina,
Kotiaho Tapio,
Franssila Sami,
Kostiainen Risto,
Ketola Raimo A.
Publication year - 2007
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.3266
Subject(s) - chemistry , electrospray , biomolecule , electrospray ionization , analytical chemistry (journal) , detection limit , mass spectrometry , chip , chromatography , biochemistry , electrical engineering , engineering
We have developed a lidless micropillar array electrospray ionization chip (µPESI) combined with mass spectrometry (MS) for analysis of drugs and biomolecules. The µPESI chip, made of silicon, contains a sample introduction spot for a liquid sample, an array of micropillars (diameter, height, and distance between pillars in the range of 15–200, 20–40, and 2–80 µm, respectively), and a sharpened tip for direct electrospray formation. The microchips were fabricated using deep reactive ion etching (DRIE) which results in accurate dimensional control. The chip, providing a reliable open‐channel filling structure based on capillary forces and a electrospray emitter tip for ionization, allows an easy operation and reliable, non‐clogging liquid transfer. The µPESI chip can be used for a fast analysis using single sampling or for continuous infusion measurements using a syringe pump for sample introduction. The µPESI‐MS shows high sensitivity, with limit of detection 30 pmol/L (60 amol or 28 fg) for verapamil measured with tandem mass spectrometry (MS/MS) and using a sample volume of 2.5 µL. The system shows also good quantitative linearity (r 2 > 0.99) with linear dynamic range of at least six orders of magnitude and good ion current stability (standard deviation <5%) in 1‐h continuous flow measurement. The µPESI‐MS is shown to be a very potential method for direct analysis of drugs and biomolecules. Copyright © 2007 John Wiley & Sons, Ltd.