Aritalab:Lecture/Biochem/Extraction
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Revision as of 12:51, 2 June 2011
Natural product chemistry starts with
- Extraction, and
- Separation & Purification.
抽出
- Like dissolves like
Solvent for extraction is chosen to share similar polarity with the target compound.
- terpenoid, steroid (alicyclics and aromatics)
→ low polarity solvent (e.g. hexane) - saccharide, glycoside, amino acid
→ high polarity solvent (e.g. water) - both
→ methanol
- Polarity (極性)
H2O > methanol > ethanol > acetone > ether > chloroform > benzene > cyclohexane
分離と精製
Chromatography separates target compounds using their physico-chemical difference in adsorption or partition between stationary and mobile phases.
- normal phase
- polarity of stationary phase > polarity of mobile phase
- silica gel + organic solvent
- cyclohexane, benzene, chloroform, ether, acetone, ethanol, methanol
- reverse phase
- polarity of stationary phase < polarity of mobile phase
- coated silica beads + water
- water + acetonitrile, water + methanol, water + tetrahydrofuran (THF)
| (High Performance) Liquid Chromatography |
Gas Chromatography | |
|---|---|---|
| Adsorption-type 吸着型 |
Liquid-solid type (LSC)
silica gel, alumina, or porous polymers are used as adsorbent.
|
Gas-solid type (GSC)
Packed column has 2∼4 mm diameter and 30∼60 cm length, and is filled with diatomite, silica and silicon oil. |
| Partition-type 分配型 |
Liquid-liquid type (LLC) uses coated-silica beads.
|
Gas-liquid type (GLC) Capillary column has 0.2 mm diameter and > 25 m length, whose inside part is coated with silicon oil. |
- シリカへの吸着度合い
-COOH ＞ -OH > -NH2 > -C=O > -OCH3 > -Cl
