Emenhiser C, Englert G, Sander L C, Ludwig B, Schwartz S J
Department of Food Science, North Carolina State University, Raleigh 27695-7624, USA.
J Chromatogr A. 1996 Jan 8;719(2):333-43. doi: 10.1016/0021-9673(95)00713-x.
The recent development and application of a polymeric C30 stationary phase have given unique separations of cis-trans carotenoid isomers in reversed-phase (RP) liquid chromatography (LC) owing to the exceptional shape selectivity of this stationary phase. In the present research, several geometrical isomers of alpha-carotene were at least partially resolved from a photo-isomerized mixture when chromatographed on a 3-microns polymeric C30 column. Double bond configurations of the five predominant alpha-carotene peaks, as isolated on a semi-preparative C30 column, were unambiguously assigned using 1H nuclear magnetic resonance (NMR) spectroscopy, giving the following order of elution: 13-cis, 13'-cis, all-trans, 9-cis, and 9'-cis geometrical forms. Electronic absorption spectra for these isomers were in agreement with the identification of peaks. The alpha-carotene isomers separated and identified herein had not been previously resolved in RPLC. Confirmation of the structures of geometrical alpha-carotene isomers will aid further studies on the possible physiological roles of these compounds in biological tissues.
由于聚合物C30固定相具有特殊的形状选择性，其最近的开发和应用使得在反相（RP）液相色谱（LC）中能够对顺反式类胡萝卜素异构体进行独特的分离。在本研究中，当在3微米的聚合物C30柱上进行色谱分析时，α-胡萝卜素的几种几何异构体至少部分地从光异构化混合物中得到分离。在半制备型C30柱上分离得到的五个主要α-胡萝卜素峰的双键构型，通过1H核磁共振（NMR）光谱被明确指定，洗脱顺序如下：13-顺式、13'-顺式、全反式、9-顺式和9'-顺式几何异构体。这些异构体的电子吸收光谱与峰的鉴定结果一致。本文中分离和鉴定的α-胡萝卜素异构体在反相液相色谱中此前尚未得到分离。对α-胡萝卜素几何异构体结构的确认将有助于进一步研究这些化合物在生物组织中可能的生理作用。
