title: Detection of aminothiols through surface-assisted laser desorption/ionization mass spectrometry using mixed gold nanoparticles.
abstract: We have employed mixtures of two differently sized (average diameters: 3.5 and 14 nm) gold nanoparticles (Au NPs) as selective probes and matrices for the determination of aminothiols using surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). When using 38 and 150 pM solutions of the 3.5- and 14-nm Au NPs, respectively, as the probe and matrix, SALDI-MS provided limits of detection (signal-to-noise ratio = 3) of 2, 20, and 44 nM for 1.0 mL solutions of glutathione (GSH), cysteine (Cys), and homocysteine, respectively. The signal intensities of these analytes varied by less than 20% for SALDI-MS analyses recorded over 50 sample spots; in contrast, they varied by as much as 60% when using a conventional matrix (2,5-dihydroxybenzoic acid). We validated the practicality of this approach - with its advantages of sensitivity, reproducibility, rapidity, and simplicity - through the analysis of GSH in MCF-7 cell lysates and Cys in plasma.
authors.affiliation: Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Ni-Chen
authors.initials: NC
authors.lastname: Chiang
authors.forename: Cheng-Kang
authors.initials: CK
authors.lastname: Chiang
authors.forename: Zong-Hong
authors.initials: ZH
authors.lastname: Lin
authors.forename: Tai-Chia
authors.initials: TC
authors.lastname: Chiu
authors.forename: Huan-Tsung
authors.initials: HT
authors.lastname: Chang
mesh_terms: D000603:Amino Acids, Sulfur / Q000097:blood / Q000737:chemistry*; D005978:Glutathione / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D008297:Male; D053768:Metal Nanoparticles / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D000603:Amino Acids, Sulfur; D006046:Gold; D005978:Glutathione