ABSTRACT
The infrared absorption of the ν3 band region of SF6, at temperatures spanning the 130 to 297 K range, has been reexamined using improved instrumentation with one goal: to estimate the broadening of parameters by nitrogen gas. These parameters are compared to previous literature predictions and an extended set of IR cross-sections is proposed and compared to other existing datasets.
ABSTRACT
Carotenoids, natural pigments, are a group of chemically heterogeneous molecules, present in numerous taxonomical clusters. Because of their various bioactivities, carotenoids are day-by-day applied in numerous fields. The present work aimed to investigate an efficient extraction process of carotenoids from blue crab shells and their identification by HR-ESI-MS technique. In this context, different methods (enzymatic, maceration, Soxhlet, etc.) and solvents (variable polarity index) were tested. Maceration using the binary system hexane/isopropanol (50/50) was found to be the most efficient process, producing high carotenoids content and low total phenolic and soluble protein amounts (pâ¯<â¯0.05). When combined with an enzymatic pretreatment, this procedure was found to be remarkably (pâ¯<â¯0.05) more efficient and selective especially towards astaxanthin (pâ¯<â¯0.05). The HR-ESI-MS identified 23 compounds, depending on the adopted extraction approach. The compounds identified may have potential for applications in food or pharmaceutical industries.
