title: Detection of carbohydrates and steroids by cation-enhanced nanostructure-initiator mass spectrometry (NIMS) for biofluid analysis and tissue imaging.
abstract: Nanostructure-initiator mass spectrometry (NIMS) is a highly sensitive, matrix-free technique that is well suited for biofluid analysis and imaging of biological tissues. Here we provide a new technical variation of NIMS to analyze carbohydrates and steroids, molecules that are challenging to detect with traditional mass spectrometric approaches. Analysis of carbohydrates and steroids was accomplished by spray depositing NaCl or AgNO(3) on the NIMS porous silicon surface to provide a uniform environment rich with cationization agents prior to desorption of the fluorinated polymer initiator. Laser desorption/ionization of the ion-coated NIMS surface allowed for Na(+) cationization of carbohydrates and Ag(+) cationization of steroids. The reliability of the approach is quantitatively demonstrated with a calibration curve over the physiological range of glucose and cholesterol concentrations in human serum (1-200 microM). Additionally, we illustrate the sensitivity of the method by showing its ability to detect carbohydrates and steroids down to the 800-amol and 100-fmol levels, respectively. The technique developed is well suited for tissue imaging of biologically significant metabolites such as sucrose and cholesterol. To highlight its applicability, we used cation-enhanced NIMS to image the distribution of sucrose in a Gerbera jamesonii flower stem and the distribution of cholesterol in a mouse brain. The flower stem and brain sections were placed directly on the ion-coated NIMS surface without further preparation and analyzed directly. The overall results reported underscore the potential of NIMS to analyze and image chemically diverse compounds that have been traditionally challenging to observe with mass spectrometry-based techniques.
authors: Department of Molecular Biology, Scripps Center for Mass Spectrometry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
authors: Gary J
authors: GJ
authors: Patti
authors: Hin-Koon
authors: HK
authors: Woo
authors: Oscar
authors: O
authors: Yanes
authors: Leah
authors: L
authors: Shriver
authors: Diane
authors: D
authors: Thomas
authors: Wilasinee
authors: W
authors: Uritboonthai
authors: Junefredo V
authors: JV
authors: Apon
authors: Rick
authors: R
authors: Steenwyk
authors: Marianne
authors: M
authors: Manchester
authors: Gary
authors: G
authors: Siuzdak
mesh_terms: D000818:Animals; D019659:Asteraceae / Q000737:chemistry; D001774:Blood Chemical Analysis / Q000379:methods*; D001923:Brain Chemistry; D002241:Carbohydrates / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D051379:Mice; D049329:Nanostructures; D013256:Steroids / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D013256:Steroids; D002784:Cholesterol