Author
Douglas A. MacFadyen
Bio: Douglas A. MacFadyen is an academic researcher from Rockefeller University. The author has contributed to research in topics: Ninhydrin & Urea. The author has an hindex of 11, co-authored 14 publications receiving 1348 citations.
Topics: Ninhydrin, Urea, Amino acid, Hydroxylysine, Excretion
Papers
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TL;DR: The method here presented depends on the fact that a-amino acids, when boiled in water with an excess of ninhydrin (triketohydrindene hydrate) at pH 1 to 5, evolve the CO2 of their carboxyl groups quantitatively in a few minutes.
426 citations
358 citations
TL;DR: In the present method, the CO2 evolved by decarboxylating amino acids with ninhydrin is transferred to standard barium hydroxide and titrated as mentioned in this paper.
168 citations
113 citations
68 citations
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TL;DR: In the present investigations of the chromatographic separation of amino acids, it has been observed that, when the color development is carried out in tubes exposed to the air, these difficulties appear to result primarily from the influence of dissolved oxygen.
2,882 citations
TL;DR: This chapter discusses the chemical analysis of microbial cells and wet- and dry-weight determinations of bacterial samples and assay of total cell numbers are described, because analytical results must refer to one or other of these values.
Abstract: Publisher Summary This chapter discusses the chemical analysis of microbial cells. The preparation of material for analysis is discussed, because changes in the chemical composition of cells may occur as a result of the washing and storage conditions used. Wet- and dry-weight determinations of bacterial samples and assay of total cell numbers are described, because analytical results must refer to one or other of these values. Selection of an analytical procedure is a subjective process, because the number of suitable methods is large and each will have different merits and defects. Primary considerations are sensitivity, specificity, reproducibility, and absolute accuracy. Automatic methods for performing biochemical analyses, already widely accepted in hospitals and in industry, are beginning to make their way into the research laboratory. All automatic analyzers developed so far may be classified as either “continuous-flow” or “discrete” types. All of them use colorimetric methods exclusively and contain some form of automatic colorimeter for final read-out. The first and best-known is the Technicon “AutoAnalyzer,” which is of the continuous-flow type.
1,193 citations
TL;DR: The kinetics of the reaction indicates that there are limits to the variation of carbodiimide and nucleophile when quantitative modification is desired, but that a wide variety of reagents can be used if quantitative reaction is not essential.
904 citations
838 citations