caa a22 4500 469039388 CHVBK 20180323132807.0 cr unu---uuuuu 170328e19921101xx s 000 0 eng 10.1007/BF00810937 doi (NATIONALLICENCE)springer-10.1007/BF00810937 Chiroptical detection during liquid chromatography, part 5: On-line measurement of circular dichroism spectra Δε(λ) during stops of chromatographic flow [Elektronische Daten] [Gert Brandl, Fritz Kastner, Rainer Fritsch, Herbert Zinner, Albrecht Mannschreck] Chiroptische Detektion während der Flüssigkeits-Chromatographie, Teil 5: On-line-Messung von Circulardichroismus-Spektren Δε(λ) während des Anhaltens des chromatographischen Flusses Summary: A procedure is described which serves to measure circular dichrograms Δε(λ) on line during stops of flow in liquid chromatography. Since the concentration of substrate in the spectrometer cell during the stop is not known, the differential absorption coefficients Δε are calculated from the experimental differential absorbances ΔA by means of UV absorption (i. e. photomultiplier voltage) data. Verifications of the procedure are obtained by its application to three substrates (Table 1), the Δε(λ) spectra of which were known. The present on-line technique is compared with a corresponding off-line method. The N,N-dimethylthiobenzamides1 and2 as well as the 9,10-phenanthrenequinone7 consist of interconvertible enantiomers because their planar states are destabilized by steric overcrowding of groups. The unknown dichrograms Δε(λ) of1, 2 and7 are obtained (Figs. 2 and 4) and discussed with reference to the helicities of these molecules. Springer-Verlag, 1992 Circular dichroism spectra nationallicence Liquid chromatography on optically active sorbents nationallicence 9,10-Phenanthrenequinones, enantiomers of nationallicence Thiobenzamides, enantiomers of nationallicence Brandl Gert Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut Kastner Fritz Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut Fritsch Rainer Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut Zinner Herbert Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut Mannschreck Albrecht Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut Monatshefte für Chemie / Chemical Monthly Springer-Verlag 123/11(1992-11-01), 1059-1069 0026-9247 123:11<1059 1992 123 706 https://doi.org/10.1007/BF00810937 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00810937 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Brandl Gert Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut NATIONALLICENCE 700 1- Kastner Fritz Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut NATIONALLICENCE 700 1- Fritsch Rainer Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut NATIONALLICENCE 700 1- Zinner Herbert Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut NATIONALLICENCE 700 1- Mannschreck Albrecht Institute of Organic Chemistry, University of Regensburg, D-8400, Regensburg, Germany aut NATIONALLICENCE 773 0- Monatshefte für Chemie / Chemical Monthly Springer-Verlag 123/11(1992-11-01), 1059-1069 0026-9247 123:11<1059 1992 123 706 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer