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F W McLafferty

Publications and source records attributed to F W McLafferty.

69 records · Page 4Linked to original sources
PubMed1985

Peptide mixture sequencing by tandem Fourier-transform mass spectrometry.

Picomole samples of the linear peptide gramicidin D and cyclic peptide gramicidin S are shown to be impure by the laser-desorption formation of multiple groups of molecular adduct peaks by using Fourier-transform mass spectrometry. Selective excitation of the molecular peaks of the major sample component followed by collisionally activated dissociation provides complete sequence information for the cyclic decapeptide and for 12 of the 15 amino acids of the linear peptide. This instrumentation shows striking advantages in sensitivity, resolution, and mass accuracy in comparison to tandem mass spectrometers used previously.

Amino Acid Sequence↗
PubMed1984

Trends in analytical instrumentation.

Methods for deriving chemical information from a variety of systems and environments have changed dramatically in the last decade. Unique principles from physics, chemistry, and biology are the basis for sophisticated instruments that incorporate computers for data acquisition, reduction, and interpretation. Such analytical systems have shown orders-of-magnitude improvements in sensitivity, specificity, and speed, yet with greater simplicity and lower price. The increasing importance of analytical instrumentation requires reexamination of its coverage in educational curricula and of the role of the analytical chemist in its further development and application.

Chemistry, Analytic↗
PubMed1981

Tandem mass spectrometry.

Coupling mass spectrometers in series provides a new technique that has many advantages for the analysis of specific organic compounds in complex mixtures. Sensitivity to picograms of targeted compounds can be achieved with high specificity and nearly instantaneous response. The targeted compound is selectively ionized, and its characteristic ions are separated from most others of the mixture in the first mass spectrometer. The selected primary ions are then decomposed by collision, and from the resulting products the final mass analyzer selects secondary ions characteristic of the targeted compound. Tandem mass spectrometry can achieve specificities and sensitivities equivalent of those of methods such as radioimmunoassay and gas chromatography/mass spectrometry, while performing analyses in much shorter times.

Gas Chromatography-Mass Spectrometry↗
PubMed1981

Tandem mass spectrometry in trace toxicant analysis.

Mass spectrometers coupled in series offer a promising technique for quantitative analysis of trace constituents in complex mixtures. Despite the relatively high cost and complexity of such instruments, this technique appears to be particularly promising in terms of the sensitivity, specificity, and speed of analysis for targeted compounds in body fluids, foods and other biological mixtures.

Body Fluids↗
PubMed1978

Polypeptide sequencing by liquid chromatography mass spectrometry.

Key steps in a proposed automated system for polypeptide sequencing utilizing a liquid chromatograph mass spectrometer computer system have been tested with mixtures containing up to six model oligopeptides. At the low nanomole level it was possible to obtain complete sequence information for all components in many, but not all, of the mixtures tried. Interpretation of the results is complicated by the presence of numerous side-products formed in the derivatization process. Minimization of such impurities will be necessary to reduce the ambiguity of the sequence information resulting from more complex mixtures, such as those expected from the degradation of larger polypeptides, and to reduce sample requirements to the subnanomole level. However, the present system appears to have unique advantages over other proposed automated methods.

Amino Acid Sequence↗