Fernando Castaño

Learn More
2-Mercaptobenzothiazole (MBT) is employed for the first time as a matrix for the analysis of lipids from tissue extracts using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. We demonstrate that the performance of MBT is superior to that of the matrixes commonly employed for lipids, due to its low vapor pressure, its low(More)
Fructose has been examined under isolation conditions using a combination of UV ultrafast laser vaporization and Fourier-transform microwave (FT-MW) spectroscopy. The rotational spectra for the parent, all (six) monosubstituted (13)C species, and two single D species reveal unambiguously that the free hexoketose is conformationally locked in a single(More)
Sugars are clearly of biochemical interest as cellular energy fuels, metabolic intermediates, mediators of cellular interactions, or structural building blocks. Recently the interest in sugars has been boosted by the quest for organic molecules in interstellar space. The detection of prebiotic building blocks is relevant both to cosmochemistry and biology,(More)
The evolution of the isolated pyrrole molecule has been followed after excitation in the 265-217 nm range by using femtosecond time delayed ionization. The transients collected in the whole excitation range show the vanishing of the ionization signal in the femtosecond time scale, caused by the relaxation along a πσ(∗) type state (3s a(1)←π 1a(2)), which is(More)
Propofol (2,6-diisopropylphenol, PPF) homodimers and their complexes with one water molecule are analyzed by means of mass-resolved excitation spectroscopy. Using two-color resonance-enhanced multiphoton ionization (REMPI) the S(1) electronic spectra of these systems are obtained, avoiding fragmentation. Due to the large size of these species, the spectra(More)
The relaxation dynamics of the isolated indole molecule has been tracked by femtosecond time-resolved ionization. The excitation region explored (283-243 nm) covers three excited states: the two ππ* L(b) and L(a) states, and the dark πσ* state with dissociative character. In the low energy region (λ > 273 nm) the transients collected reflect the absorption(More)
The infrared extinction spectra of aqueous NaBr aerosols at ambient temperature have been measured as a function of relative humidity. Submicron-sized aerosol particles atomized from aqueous NaBr solutions at various concentrations are dried and/or mixed with nitrogen at different humidities and spectroscopically monitored as they flow through an infrared(More)
The conformational equilibria of vanillin and ethylvanillin have been investigated in a supersonic jet expansion using rotational spectroscopy. Two conformers have been detected for each molecule, with a dominant O-H···O intramolecular hydrogen bond locking the local conformation of the hydroxyl and methoxy/ethoxy groups. As a consequence, the observed(More)
Propofol is a general anaesthetic that exerts its action by interaction with the GABA(A) receptor. Crystallographic studies suggest that there is a direct interaction between propofol and the phenolic residue of a tyrosine in the channel. In this study we create propofol···phenol clusters by their co-expansion in jets. The complex is probed using a set of(More)
Cooperativity between weak hydrogen bonds can be revealed in molecular clusters isolated in the gas phase. Here we examine the structure, internal dynamics, and origin of the weak intermolecular forces between sevoflurane and a benzene molecule, using multi-isotopic broadband rotational spectra. This heterodimer is held together by a primary C-H⋅⋅⋅π(More)