title: Parylene-matrix chip for small molecule analysis using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
abstract: BACKGROUND
  In matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS), analyte molecules are known to be ionized by mixing with organic matrix molecules. As the organic matrix molecules are ionized, they generate unreproducible mass peaks such that MALDI-TOF MS is nearly impossible in the low mass-to-charge (m/z) range (<1000). In this work, we aimed to develop a parylene-matrix chip for the detection of small molecules in the low m/z range by using MALDI-TOF MS.
  
  
  METHODS
  The parylene-matrix chip was fabricated by the deposition of a partially porous parylene-N thin film on a dried organic matrix array. The properties of the parylene thin film were analyzed by atomic force microscopy (AFM) and cyclic voltammetry (CV). Mass spectrometry was performed by using a parylene-matrix chip with eight amino acids as model analytes.
  
  
  RESULTS
  The surface roughness and the electric conductivity of the parylene-N film were analyzed by AFM and CV analysis to determine its suitability for a parylene-matrix chip. The ionization of samples on the parylene-matrix chip was optimized by adjusting the laser intensity. The feasibility of applying a parylene-matrix chip for small molecule analysis was tested by using eight kinds of amino acids as model analytes and the simultaneous detection of multiple analytes from the amino acid mixture was also demonstrated.
  
  
  CONCLUSIONS
  The parylene-matrix chip can be applied for the detection of multiple analytes in the m/z ratio range of small molecules (<1000) using MALDI-TOF MS.
authors.affiliation: Department of Materials Sciences and Engineering, Yonsei University, 134 Shin-chon-dong, Seo-dae-mun-gu, Seoul, 120-749, Korea.
authors.forename: Jo-Il
authors.initials: JI
authors.lastname: Kim
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Park
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Kang
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Pyun
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000737:chemistry; D057230:Limit of Detection; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation* / Q000379:methods*; D014992:Xylenes / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D011108:Polymers; D014992:Xylenes; C011055:parylene