Kakiuchi M, Tsuji S, Shibata T, Ito Y
Eisei Shikenjo Hokoku. 1990(108):114-7.
It is very difficult to determine the content of sulfate in food coal-tar dye by the method designated in the "Japanese Standards of Food Additives(V)", because the endpoint on titration is difficult to gauge. We determined the concentration of sulfate in food dye nephelometrically after decolorization with charcoal but obtain different values depending on the kind of charcoal used. Because the adsorbed or eluted sulfate in the various charcoals were dispersed widely, so we tested the sulfate contents in five kinds of charcoals. It was found that all kinds of charcoals eluted or adsorbed sulfate in varying degrees. Therefore no charcoal was found to be satisfactory for use in the sulfate test.
采用《日本食品添加剂标准（第五版）》中规定的方法测定食用煤焦油染料中的硫酸盐含量非常困难，因为滴定终点难以判断。我们用木炭脱色后，通过比浊法测定食用染料中的硫酸盐浓度，但根据所用木炭的种类不同，得到的值也不同。由于各种木炭对硫酸盐的吸附或洗脱情况差异很大，所以我们测试了五种木炭中的硫酸盐含量。结果发现，各种木炭对硫酸盐的洗脱或吸附程度各不相同。因此，未发现有哪种木炭适用于硫酸盐检测。
