Separation Characteristics of Mandelic Acid in Kromasil HPLC Column

Chiral separation of racemic mandelic acid was achieved on a Kromasil KR100-5CHI-TBB column. Some chromatographic parameters (resolution, number of theoretical plates, capacity factor) are calculated under different separation conditions such as changes of mobile phase compositions (hexane/t-BME = 85/15 - 10/90) as well as formic acid concentrations for adjusting pH (0.1, 0.5, 1.0 v/v%). Flow rate versus number of theoretical plates was compared to evaluate column efficiency. To determine the adsorption isotherms, PIM (Pulse Input Method) was carried out. At the concentrations of racemic mandelic acid between 0.1 and 0.3 mg/ml, L- and D-mandelic acids have the same retention times of 8.8 and 9.4 min respectively. Mandelic acid isotherms show a linear form under the concentrations of 0.3 mg/ml with eluent (hexane/t-BME = 75/25). As the concentrations of mandelic acids increase, nonlinear Langmuir isotherms were observed as $C_{S,L}=3.358C_{M,L}/(1+0.0897C_{M,L})$ for L-mandelic acid and, $C_{S,D}=3.692C_{M,D}/(1+0.1457C_{M,D})$ for D-mandelic acid.

Kromasil HPLC 칼럼에서 Mandelic Acid의 분리특성

Kromasil KR100-5CHI-TBB 칼럼을 사용하여 라세미 mandelic acid를 분리하였다. 분리도(resolution), 이론단수(number of theoretical plates), 용량인자(capacity factor)와 같은 크로마토그라피 변수들을 이동상의 조성(hexane/t-BME = 85/15 - 10/90)과 포름산 농도(0.1, 0.5, 1.0 v/v%)를 변화시켜 실험하여 계산하였다. 칼럼의 효율을 평가하기 위해 유속 대 이론단수를 비교하였다. 등온흡착식을 계산하기 위해 PIM(Pulse Input Method)을 사용하였고, mandelic acid의 농도가 0.1에서 0.3 mg/ml 사이일 때 L-과 D-mandelic acid가 각각 8.8분과 9.4분의 체류시간을 보였다. Mandelic acid의 등온흡착식은 0.3 mg/ml의 농도이하와 이동상 조성(hexane/t-BME = 75/25)에서 선형이었다. Mandelic acid의 농도가 증가할수록 mandelic acid는 비선형 거동을 보였고, Langmuir 등온흡착식은 L-과 D-mandelic acid의 경우 각각 $C_{S,L}=3.358C_{M,L}/(1+0.0897C_{M,L})$, $C_{S,D}=3.692C_{M,D}/(1+0.1457C_{M,D})$이었다.