Abstract
In measuring separatively contents of tocopherols in oil by high performance liquid chromatography (HPLC), measurement conditions such as packing agent and mobile phase were investigated. Then, a collaborative study was conducted with 6 laboratories, using distributed standard solution of tocopherols and specified packing agent and mobile phase. Results obtained were as follows :
1) It was found that fatty components were eluted together with α-tocopherol fraction by using some of mobile phase which could separate tocopherols one another, consequently lowering measurement values.
2) The response of fluorescent detector for each tocopherol was found to change with time when this detector was contenuously used for long time.
3) There was no difference in the precision of separation and detection of tocopherols when different brands of silica gel packing agent were used.
4) In measuring oils by HPLC without pretreatment, a measurement error was up to ±3% for individual tocopherol content of 10 mg/100 g or more, but over ±10% for smaller amounts.
