Új fotometrikus cukormeghatározási eljárás

Verfasser reduzieren alkalische Kupfertaitaratkomplexe mit dem zu bestimmenden Zucker und bestimmen den überschüssigen Kuprikom plexphotometrisch. Das Verfahren eignet sich wegen seiner raschen Durch ­ führbark eit besonders für Serienprüfungen. The authors reduce an alkaline cupric complex with the sugar in question and determine the superfluous cupric complex photometrically. Owing to its rapidity the method is especially advantageous for serial analysis

Single- and multi-photon excited fluorescence from serotonin complexed with B-cyclodextrin

The fluorescence of serotonin on binding with B-cyclodextrin has been studied using both steady-state and time-resolved methods. Steady state fluorescence intensity of serotonin at 340 nm showed ~ 30% increase in intensity on binding with Ka ~ 60 dm3 mol 1 and the fluorescence lifetimes showed a corresponding increase. In contrast, the characteristic green fluorescence (‘hyperluminescence’) of serotonin observed upon multiphoton near-infrared excitation with sub-picosecond pulses was resolved into two lifetime components assigned to free and bound serotonin. The results are of interest in relation to selective imaging and detection of serotonin using the unusual hyperluminescence emission and in respect to recent determinations of serotonin by capillary electrophoresis in the presence of cyclodextrin. The results also suggest that hyperluminescence occurs from multiphoton excitation of a single isolated serotonin molecule