title: Enhanced specificity for phosphatidylcholine analysis by positive ion mode matrix-assisted laser desorption/ionization imaging mass spectrometry.
abstract: BACKGROUND
  Visualization of the spatial distribution of phosphatidylcholine (PC) in tissues by matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) provides insights into key physiological and pathophysiological processes. In MALDI-IMS analysis, the heterogeneity of adduct ions formed from PC lowers the specificity of detection of PC molecular species and poses a challenge in the identification of these species. To solve this problem, modified matrix solution and desalting with ammonium acetate (NH4 Ac) buffer have been employed. However, the utility of these methods is limited to the analysis of brain sections.
  
  
  METHODS
  The MALDI signal intensities of [PC+H], [PC+Na] and [PC+K] were compared after three different pretreatments (modified matrix solution, desalting with 150 mM ammonium acetate, treatment with 150 mM potassium acetate).
  
  
  RESULTS
  Pretreatment of tissue sections with 150 mM potassium acetate resulted in an increase in the signal intensity of [PC+K] ions produced from cryosections of the pancreas, brain, and liver tissues.
  
  
  CONCLUSIONS
  Pretreatment with potassium acetate can be a simple, improved, and highly useful method for the reliable analysis of PC in tissues.
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agriculture, Kinki University, Nara, 631-8505, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Zaima
authors.forename: Sayaka
authors.initials: S
authors.lastname: Yoshioka
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Sato
authors.forename: Saki
authors.initials: S
authors.lastname: Shinano
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Moriyama
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D006801:Humans; D008099:Liver / Q000737:chemistry; D008297:Male; D051379:Mice; D057054:Molecular Imaging / Q000379:methods*; D010179:Pancreas / Q000737:chemistry; D010713:Phosphatidylcholines / Q000032:analysis* / Q000737:chemistry; D019347:Potassium Acetate; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D010713:Phosphatidylcholines; D019347:Potassium Acetate