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  • Analytical Chemistry and Spectroscopy  (1)
  • Carotenoids  (1)
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Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 156 (1996), S. 71-73 
    ISSN: 1432-1076
    Keywords: Key words Antioxidants ; Carotenoids ; β-carotene ; Lycopene ; Cryptoxanthin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Carotenoids are important antioxidants and precursors of vitamin A, but only few studies have been carried out on plasma carotenoid levels in paediatric age groups. Using high-performance liquid chromatography we analysed concentrations of four important carotenoids (α-carotene, β-carotene, cryptoxanthin, lycopene) in 129 healthy German children and adolescents (81 boys, 48 girls; age 1–18 years). For all carotenoids analysed, no significant differences between girls and boys were found. α-Carotene values ranged from 0 μmol/l (below detection limits) to 0.73 μmol/l (0–395 μg/l), β-carotene from 0.09 μmol/l to 2.68 μmol/l (48–1443 μg/l), lycopene from 0 μmol/l to 1.51 μmol/l (0–815 μg/l), and cryptoxanthin from 0 μmol/l to 0.30 μmol/l (0–164 μg/l), respectively. Data analyses according to age groups showed a tendency towards higher levels of α- and β-carotene, and lower levels of lycopene in young children. These differences were significant when children younger than 4 years were compared with those above 8 and 12 years, respectively. The data presented may serve as reference values for studies on children with nutritional disorders and diseases associated with a risk of vitamin deficiencies. Conclusion Carotenoids are important antioxidants and singlet oxygen scavengers. Plasma levels of α-carotene, β-carotene, lycopene and cryptoxanthin were determined in 129 healthy German children and adolescents. Highest values were found for β-carotene and lycopene.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 13 (1982), S. 139-148 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of the depolarization ratio of the four resonant Raman lines at 1375 cm-1, 1506 cm-1, 1583 cm-1, and 1638 cm-1 were performed for all exciting wavelengths of an Argon ion laser. The results show a significant variation of the depolarization ratio in the wavelength region between the Soret- and β-bands. The dispersion curves have a different shape for the four Raman lines. Measurements of the depolarization ratio at three pH-values (pH = 6.3, pH = 7.4, pH = 8.0) and two haemoglobin concentrations (c = 1.2 × 10-4 M, c = 5 × 10-5M) of the solution show that the concentration and the pH-value change the dispersion curve in a similar way. The depolarization ratio of the 1375-Raman line at 496.5 nm excitation wavelength was measured for different concentrations in a region between 4 × 10-4M and 4 × 10-5M. With decreasing concentration the DPR increases. This effect is interpreted as being caused by the dimerization of the tetrameric oxyhaemoglobin molecule. The dispersion curves ρ(λ) are interpreted in terms of mode mixing of the molecular vibrations of the haem due to symmetry lowering of its environment. This symmetry change is induced by interactions of the solvent with the charged and polar groups on the surface of the globular protein.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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