Colorimetric Determination of ${\alpha}-Cyclodextrin$ by Using the Decoloration of Starch-iodine Complex

Starch-iodine Complex의 변색반응을 이용한 ${\alpha}-Cyclodextrin$의 정량

A new colorimetric method to analyze ${\alpha}-Cyclodextrin({\alpha}-CD)$ by using a property of ${\alpha}-CD$ to decolor the starch-iodine complex, was presented. ${\alpha}-CD$ was quantitatively determined as follows. The ${\alpha}-CD$ standard solutions at concentrations up to 2 mg/ml were prepared. To 1ml of starch-iodine complex solution which contained starch(1%) and iodine (0.02% $I_2$, 0.2% KI) equivalently in distilled water, $200\;{\mu}l$ of ${\alpha}-CD$ standard solutions and 3 ml of distilled water were added and the absorbance was measured at 570 nm. Using this mothod ${\alpha}-CD$ concentration range at $0{\sim}2\;mg/ml$ could be determined and their absorbance patterns at 570 nm showed a good linearity. ${\beta}(CD)$ and glucose had no interference in this method for ${\alpha}-CD$ determination.

${\alpha}-Cyclodextrin(CD)$이 starch-iodine 복합체를 변색시킬 수 있다는 성질을 이용하여 ${\alpha}CD$의 새로운 비색정량법을 확립하였다. 이 새로운 ${\alpha}CD$의 정량법은 다음과 같다. ${\alpha}CD$의 표준용액을 2 mg/ml까지 농도별로 준비하였다. 그리고 동량으로 혼합된 starch-iodine 복합체 용액 1ml에 ${\alpha}CD$ 표준용액 $200\;{\mu}l$와 증류수 3 ml를 함께 가하고, 570 nm에서 흡광도를 측정하였다. 이 방법으로 ${\alpha}CD$의 농도범위는 $0{\sim}2\;mg/ml$까지 측정할 수 있었고, 570 nm에서의 흡광도도 가장 좋은 직선성을 나타내었다. 한편, ${\beta}CD$와 glucose는 ${\alpha}CD$ 정량을 위한 본 방법에 아무런 방해효과가 없었다.