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The electrospray ionization (ESI) mass spectra of 16 cinchona alkaloid compounds were studied for the first time. The electron ionization (EI) spectra of 22 cinchona alkaloids were also recorded, 14 of which had not been examined previously. In the case of EI the characteristic direction of the fragmentation is the scission of the C8-C9 bond. Under EI the cleavage of the C4'-C9 bond occurs only in the case of hydrogenated cinchona alkaloids, whereas the C9-O bond cleavage can be observed in the case of ester and ether derivatives. At a low capillary exit voltage (CapEx) in the ESI measurements there is no fragmentation, and only the [M + H](+) and in some cases the double protonated [M + 2H](2+) ions can be detected. On increasing the CapEx the characteristic primary direction is the cleavage of the C9-O bond, which was observed in the case of epialkaloids and esterified or etherified cinchona derivatives, respectively. Copyright 2000 John Wiley & Sons, Ltd.

Prompted by the near infrared-absorbing properties of some of the azulenic bacteriorhodopsin (bR) analogs, we have analyzed their absorption characteristics along with 11 new related ring-fused analogs and the corresponding Schiff bases (SB) and protonated Schiff bases (PSB). The following three factors are believed to contribute to the total red shift of each of the pigment analogs (sigma RS): perturbation of the basic chromophore (SB shift, delta SB), protonation of the SB (PSB shift, PSBS) and protein perturbation (the opsin shift, OS). For each factor, effects of structural modifications were examined. For the red-shifted pigments, percent OS has been suggested as an alternate way of measuring protein perturbation. Computer-simulated chromophores provided evidence against any explanation involving altered shapes of the binding pocket as a major cause for absorption differences. Implications of the current bR results on preparation of further red-shifted bR and possible application to visual pigment analogs are discussed.

Supercritical CO2 (SCO2) can be utilized to extract oils from a number of plant materials as a nontoxic alternative to hexane, and there is industrial interest in using SCO2 extraction to obtain high-quality oils for cosmetics and other high-value applications. A possible substrate is rosehip (Rosa aff. rubiginosa) seed. The scope of our work was to select SCO2 extraction conditions and to compare cold-pressed, hexane-extracted and SCO2-extracted rosehip oil. We used a fractional factorial experimental design with extraction temperature (T, 40-60 °C), extraction pressure (p, 300-500 bar) and dynamic extraction time (t, 90-270 min) as independent variables and yield and color as response variables. Samples of 100 g flaked rosehip seeds were extracted with 21 g CO2/min, following a static extraction (15 min adjustment) period. Resulting data were analyzed using response surface methodology. Extracted oil (4.7-7.1% in our experimental region) increased slightly with p and more pronouncedly with T and specially t. On the other hand, the photometric color index was independent of t but worsened (increased) as a result of an increase in either p or specially T. We extracted five batches of 250 g seeds with 21 g CO2/min at 40 °C and 300 bar for 270 min and compared the oil with samples obtained by solvent extraction (a batch of 2.5 kg of laminated seeds was treated with 10 L hexane and rotaevaporated until there was virtually no residual hexane) and cold pressing, by determining color, fatty acid composition, iodine index and saponification index. It was concluded that SCO2 allows an almost complete recovery of rosehip oil (6.5% yield), which is of a better quality than the oil extracted with hexane. Yield was higher than it was when using a cold-pressing process (5.0% yield)