Harvey S. Gold

Analysis of binary mixtures by computer decomposition of molecular fluorescence spectra

Abstract Qualitative analysis by computer decomposition of fluorescence spectra by means of the program SPECSOLV is discussed. Concentration studies of naphthacene in benzene and mixture analyses of single and binary solutions of anthracene, naphthacene, naphthalene,and rubrene are reported. The results demonstrate the ability to separate solvent and sample spectral contributions, and to assign component peaks in the case of mixtures. Semi-quantitative results are presented, and the feasibility of extending the study to computersearch systems based on component characterization of fluorescence spectra is discussed.

Principal component and decomposition analysis of multicomponent mixtures of carcinogenic fluorophores

Abstract A series of binary and tertiary mixtures of polycyclic aromatic hydrocarbons is analyzed by using principal component and decomposition analysis of molecular fluorescence spectra. The results demonstrate the ability to determine the number and identity of species that are present. Failures caused by high correlation among spectra are considered.

Aldol condensation of butan-2-one and pentan-3-one on an activated alumina as monitored via in-situ carbon-13 nuclear magnetic resonance spectroscopy

Conventional 13C nuclear magnetic resonance spectroscopy is used to monitor the reactions of butan-2-one and pentan-3-one adsorbed on alumina. Both reaction sequences proceed via successive aldol condensations. The products observed for butan-2-one (5-methyl-4-hepten-3-one and 4-hydroxy-4-methylpentan-2-one) are those expected for homogeneous base catalysis. A J-modulated spin–echo sequence demonstrates that 5-ethyl-4-methyl-5-hepten-3-one, the β, γ condensation product, is obtained using pentan-3-one. The results demonstrate that conventional 13C n.m.r. can be effectively used to distinguish reaction pathways and products for surface-catalysed reactions.

Sample Preparation Facilities For Inelastic Electron Tunneling Spectroscopy

ABSTRACT The design and operation of sample preparation equipment utilized in inelastic electron tunneling spectroscopy is described. This equipment has been assembled in the bell jar of a commercially available vacuum deposition facility.

Quantitative analysis for polycyclic aromatic hydrocarbons by spectral decomposition of molecular fluorescence

Abstract Analysis of the molecular fluorescence spectra of several polycyclic aromatic hydrocarbons (PAH) by the technique of spectral decomposition is discussed. Peak characterization parameters obtained by this technique are utilized to obtain quantitative measurement of a mixture containing benzidiae and dibenzochrysene in solution. Application of the technique to a large number of reference compounds is discussed as an aid to routine identification of suspected carcinogens and other compounds containing fluorophores.

Effect of Modulation Source Properties upon Signal-to-Noise Ratios of Inelastic Electron Tunneling Spectra

Lock-in amplification using ac modulation and second-harmonic detection is routinely employed in such techniques as ac polarography, ac voltammetry, and inelastic electron tunneling spectroscopy (IETS). Properties of the modulation source are shown in the present IET studies to limit the obtainable signal-to-noise ratio of a spectrum. A single inelastic electron tunneling junction is used to demonstrate the effect of various commercial modulation sources on the IET spectrum of benzoic acid on alumina. With all other parameters being held constant, the signal-to-noise ratio of the IET spectrum is found to be inversely correlated with the total harmonic distortion of the modulation source.