title: Semiconductor cadmium sulphide nanoparticles as matrices for peptides and as co-matrices for the analysis of large proteins in matrix-assisted laser desorption/ionization reflectron and linear time-of-flight mass spectrometry.
abstract: The use of semiconductor cadmium sulphide nanoparticles (CdS NPs) capped with 4-aminothiophenol (ATP) and 11-mercaptoundecanoic acid (MUA) is described for the first time as matrices and as co-matrices for the analysis of peptides and proteins in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). UV-visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied for the characterization of functionalized CdS NPs. The synthesized CdS-ATP and CdS-MUA NPs exhibit uniform size distribution with diameter of 15-25 nm and 20-30 nm, respectively. The -NH(2) (ATP) and -COOH (MUA) groups modified on the surfaces of CdS NPs provide ionizable moieties for efficient transfer of protons during the desorption/ionization of analytes. The functionalized CdS NPs have desirable properties for the analysis of peptides in reflectron MALDI-TOF-MS with suppressed background noise and increased mass resolution (4-13-fold) in linear MALDI-TOF-MS. The application of CdS-MUA NPs and SA as the co-matrices in MALDI-MS is demonstrated for the analysis of hydrophobic proteins from soybean.
authors.affiliation: Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, 80424, Taiwan.
authors.forename: Suresh Kumar
authors.initials: SK
authors.lastname: Kailasa
authors.forename: Hui-Fen
authors.initials: HF
authors.lastname: Wu
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D019187:Cadmium Compounds / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008854:Microscopy, Electron; D010316:Particle Size; D010455:Peptides / Q000737:chemistry*; D045663:Quantum Dots; D030262:Soybean Proteins / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry*
chemical_list: C505222:11-mercaptoundecanoic acid; D000814:Aniline Compounds; D019187:Cadmium Compounds; D005227:Fatty Acids; D010455:Peptides; D030262:Soybean Proteins; D013438:Sulfhydryl Compounds; D013440:Sulfides; C034939:cadmium sulfide; C064316:4-aminothiophenol