Standaard Boekhandel gebruikt cookies en gelijkaardige technologieën om de website goed te laten werken en je een betere surfervaring te bezorgen.
Hieronder kan je kiezen welke cookies je wilt inschakelen:
Technische en functionele cookies
Deze cookies zijn essentieel om de website goed te laten functioneren, en laten je toe om bijvoorbeeld in te loggen. Je kan deze cookies niet uitschakelen.
Analytische cookies
Deze cookies verzamelen anonieme informatie over het gebruik van onze website. Op die manier kunnen we de website beter afstemmen op de behoeften van de gebruikers.
Marketingcookies
Deze cookies delen je gedrag op onze website met externe partijen, zodat je op externe platformen relevantere advertenties van Standaard Boekhandel te zien krijgt.
Je kan maximaal 250 producten tegelijk aan je winkelmandje toevoegen. Verwijdere enkele producten uit je winkelmandje, of splits je bestelling op in meerdere bestellingen.
0. ISLER Chemical Research Department, F. Hoffmann-LaRoche&Co. Ltd., Basle, Switzerland A. General Remarks . . . 12 B. Historical Development 13 C. Scope and Limitations 15 D. Vitamins A and Provitamins A . 15 E. Carotenoids as Natural Colouring Matters . 19 F. Other Natural Pigments and Related Compounds. 21 G. Nomenclature . . . 22 H. Lists of Carotenoids 24 I. Acknowledgments 25 References . . . . . . 25 0. ISLER 12 A. General Remarks The brightly coloured carotenoid pigments have aroused the curiosity of scientists since the beginning of organic chemistry. Indeed some of the oldest studies were published during the early 19th century. Research on carotenoids can be separated into four broad periods according to the selection of problems and the methods of attacking them. During the 19th century, the emphasis was on isolation of the pigments and their characterization by measurements of light absorption. The second period (1900-1927) centred on the determination of empirical formulae and on tentative efforts to discover a role in photosynthesis. The third period (1928-1949) was dominated by the provitamin A concept, by establishing structural formulae and developing synthetic methods. The latest period (1950 to the present) has seen an expo nential increase in the number of known carotenoids accompanied by notable advances in total synthesis and in the determination of absolute configura tions. The recent explosive growth in knowledge has in no small part been due to new separation methods (e. g."