Withnall Robert, Chowdhry Babur Z, Silver Jack, Edwards Howell G M, de Oliveira Luiz F C
School of Chemical and Life Sciences, University of Greenwich, Pembroke, Chatham Maritime Campus, Chatham, Kent ME4 4TB, UK.
Spectrochim Acta A Mol Biomol Spectrosc. 2003 Aug;59(10):2207-12. doi: 10.1016/s1386-1425(03)00064-7.
Resonance Raman spectra of naturally occurring carotenoids have been obtained from nautilus, periwinkle (Littorina littorea) and clam shells under 514.5 nm excitation and these spectra are compared with the resonance Raman spectra obtained in situ from tomatoes, carrots, red peppers and saffron. The tomatoes, carrots and red peppers gave rise to resonance Raman spectra exhibiting a nu1 band at ca. 1520 cm(-1), in keeping with its assignment to carotenoids with ca. nine conjugated carbon-carbon double bonds in their main chains, whereas the resonance Raman spectrum of saffron showed a nu1 band at 1537 cm(-1) which can be assigned to crocetin, having seven conjugated carbon-carbon double bonds. A correlation between nu1 wavenumber location and effective conjugated chain length has been used to interpret the data obtained from the shells, and the wavenumber position (1522 cm(-1)) of the nu1 band of the carotenoid in the orange clam shell suggests that it contains nine conjugated double bonds in the main chain. However, the black periwinkle and nautilus shells exhibit nu1 bands at 1504 and 1496 cm(-1), respectively. On the basis of the correlation between nu1 wavenumber location and effective conjugated chain length, this indicates that they contain carotenoids with longer conjugated chains, the former having ca. 11 double bonds and the latter ca. 13 or even more. Raman spectra of the nautilus, periwinkle and clam shells also exhibited a strong band at 1085 cm(-1) and a doublet with components at 701 and 705 cm(-1), which can be assigned to biogenic calcium carbonate in the aragonite crystallographic form.
在514.5nm激发下，已获得鹦鹉螺、滨螺（Littorina littorea）和蛤壳中天然存在的类胡萝卜素的共振拉曼光谱，并将这些光谱与从番茄、胡萝卜、红辣椒和藏红花原位获得的共振拉曼光谱进行了比较。番茄、胡萝卜和红辣椒产生的共振拉曼光谱在约1520cm-1处呈现一个ν1带，这与其被指定为在主链中约有9个共轭碳 - 碳双键的类胡萝卜素一致，而藏红花的共振拉曼光谱在1537cm-1处显示一个ν1带，可归属于具有7个共轭碳 - 碳双键的藏红花酸。ν1波数位置与有效共轭链长度之间的相关性已被用于解释从贝壳获得的数据，橙色蛤壳中类胡萝卜素的ν1带的波数位置（1522cm-1）表明其主链中含有9个共轭双键。然而，黑色滨螺和鹦鹉螺壳分别在1504和1496cm-1处呈现ν1带。基于ν1波数位置与有效共轭链长度之间的相关性，这表明它们含有共轭链更长的类胡萝卜素，前者约有11个双键，后者约有13个或更多双键。鹦鹉螺、滨螺和蛤壳的拉曼光谱在1085cm-1处也呈现出一个强带以及一个在701和705cm-1处有组分的双峰，这可归属于文石晶体形式的生物源碳酸钙。
