The study on the structure of pigments in the outer skin of squid

用HCl/甲醇混合溶液从日本飞鱿鱼的外皮中提取红色色素。反相LC-ESI-MS分析表明，提取物中存在黄胚素及其衍生物黄色共色素，但未洗脱红色色素。在溶剂中加入离子对试剂进行高效液相色谱分析，发现提取物中存在多种色素。所观察到的色素的最大吸光度波长在450 nm ~ 530 nm之间，说明所制备的提取物含有黄色、红色、红紫色等多种色素。提取物通过正离子交换和随后的反相色谱分离，得到亲水性红色颜料。UPLC-TOF-MS分析表明，红色色素的分子量在450 ~ 800 Da之间，表明色素分子中存在硫。

The red pigments were extracted from the outer skin of Japanese flying squid Todarodes pacificus with HCl/methanol mixture solution. The reverse-phase LC-ESI-MS analysis of the extract showed the presence of xanthommatin and derivatives, yellow ommochrome pigments, in the extract, but red pigments were not eluted. The HPLC analysis with solvents added a ion-pair reagent revealed the presence of various pigments in the extracts. The wavelength of maximum absorbances of the observed pigments were in the range of 450 nm to 530 nm, indicating the extracts to be composed with various pigments containing yellow, red and red-purple color. The extract was partitioned by a positive ion-exchange and a subsequent reverse-phase chromatographies, which yielded hydrophilic red pigments. The UPLC-TOF-MS analysis of the red pigments indicated that the molecular weight of the pigments were between 450 and 800 Da and suggested the presence of sulfur in the pigment molecules.