Crews H M, Dean J R, Ebdon L, Massey R C
Analyst. 1989 Aug;114(8):895-9. doi: 10.1039/an9891400895.
The speciation of cadmium in retail pig kidney has been examined by size-exclusion chromatography (SEC) coupled directly to inductively coupled plasma mass spectrometry (ICP-MS). Approximately 35% of the cadmium from uncooked kidney was soluble after aqueous extraction at pH 8 and SEC - ICP-MS revealed three discrete peaks whose retention times corresponded to estimated relative molecular masses of 1.2 x 10(6), 7.0 x 10(4) and 6 x 10(3)-9 x 10(3). In the cooked kidney, 35% of the Cd was soluble and was all associated with a peak of a relative molecular mass (Mr) of 6 x 10(3)-9 x 10(3). After simulated gastric digestion of cooked pig kidney at pH 2.5, 60% of the cadmium was solubilised and associated with a species of Mr less than 1 x 10(3). When the digest was also subjected to simulated intestinal digestion at pH 6.8, a single peak, which corresponded to 20% of the original cadmium, was eluted. This peak co-eluted with the single peak extracted at pH 8.0 from the cooked kidney. It was also of similar estimated Mr to the single broad peak observed after simulated gastro-intestinal digestion of equine renal metallothionein (Mr = 1.1 x 10(4]. The results suggest that the majority of soluble cadmium in retail pig kidney is associated with a metallothionein-like protein that survives both cooking and simulated in vitro gastro-intestinal digestion.
通过直接与电感耦合等离子体质谱（ICP-MS）联用的尺寸排阻色谱法（SEC），对市售猪肾中镉的形态进行了研究。在pH 8的水相萃取后，生肾中约35%的镉可溶，SEC - ICP-MS显示出三个离散峰，其保留时间对应于估计相对分子质量分别为1.2×10⁶、7.0×10⁴和6×10³ - 9×10³。在熟肾中，35%的镉可溶，且都与相对分子质量（Mr）为6×10³ - 9×10³的一个峰相关。在pH 2.5对熟猪肾进行模拟胃消化后，60%的镉溶解，并与Mr小于1×10³的一种物质相关。当消化物在pH 6.8也进行模拟肠消化时，洗脱得到一个对应于原始镉20%的单峰。该峰与在pH 8.0从熟肾中萃取的单峰共洗脱。其估计的Mr也与马肾金属硫蛋白模拟胃肠消化后观察到的单一宽峰相似（Mr = 1.1×10⁴）。结果表明，市售猪肾中大部分可溶镉与一种类似金属硫蛋白的蛋白质相关，这种蛋白质在烹饪和模拟体外胃肠消化过程中均能留存。
