The speciation analysis of cadmium in the scallop (Chlamys farreri, C. farreri) with high Cd accumulation capability and the clam (Ruditapes philippinarum, R. philippivarum) with low Cd accumulation capability was first conducted by size exclusion chromatography-high performance liquid chromatography-inductivcly coupled plasma mass spectrometry (SEC-HPLC-ICP-MS), and in vitro whole-bionic digestion model was used to determine the cadmium speciation in two bivalves under the action of saliva, the acidity of stomach and intestine with inorganic and organic components and diges-tion enzymes. The results showed that the total cadmium content in C. farreri was almost 10 times in R. philippinarum. Three Cd species, metallothionein (MT)-Cd, glutathione (GSH)-Cd and cystein (Cys)-Cd were detected in C. farreri, and two Cd species, MT-Cd and GSH-Cd were detected in R. philippinarum. According to the different peak areas, MT-Cd and GSH-Cd content in C. farreri was about 5. 6 and 2. 0 times of those in R. philippinarum respectively. Using in vitro whole-bionic diges-tion model, one unknown Cd species with small molecule (named Cd-X) was detected in whole-bionic digestion of gastric extracts, and four Cd species (mainly MT-Cd) were detected in the whole-bionic digestion of intestine extracts for C. farreri; however, for R. philippinarum, the unknown Cd-X was the main Cd species in both gastric and intestinal extracts. The experiment also proves that Cd can be separated from MT-Cd, GSH-Cd and Cys-Cd under the effect of the whole-bionic digestion of stomach and intestine.%运用体积排阻高效液相色谱-电感耦合等离子体质谱联用技术(SEC-HPLC-ICP-MS)分析了高镉积累扇贝和低镉积累菲律宾蛤仔中镉的存在形态,并结合体外全仿生消化技术,研究了在唾液、胃、肠无机物和有机物(含消化酶)作用下,扇贝和菲律宾蛤仔中镉的主要存在形态.结果发现:扇贝中Cd总量约为菲律宾蛤仔的10倍；在扇贝中检测到3种Cd形态:金属硫蛋白(MT)-Cd、谷胱甘肽(GSH) Cd和半胱氨酸(Cys)-Cd；在菲律宾蛤仔中检测到2种Cd形态:MT-Cd和GSH-Cd;以峰面积作参考进行比较,扇贝中MT-Cd和GSH-Cd含量分别约为菲律宾蛤仔的5 6和2.0倍.结合体外全仿生模型发现,在扇贝胃全仿生提取液中,检测到1种未知小分子有机镉形态(Cd-X),在扇贝肠全仿生提取液中检测到4种Cd形态,其中MT-Cd是主要形态；而在菲律宾蛤仔胃、肠全仿生提取液中均仅检测到1种未知小分子有机态镉(Cd-X).本实验证明贝类中的MT-Cd,GSH-Cd,Cys-Cd中络合的Cd在生物体胃肠消化液作用下会发生解离.
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