Thin Layer Chromatography
• Consisted of a stationary phase immobilized on a glass or plastic plate and an organic solvent.
• Sample, either liquid or dissolved in a volatile solvent, is applied as a spot on stationary phase.
• The bottom-edge of plate is put in a solvent reservoir afterwards the solvent moves up onto plate by capillary force
• When the solvent front reaches the other edge then
the plate is removed from the solvent reservoir
Thin Layer Chromatography
• Separated spots are
visualized by ultraviolet
light or placing the plate in
iodine vapor.
• Different components in the mixture move up the plate at different rates due to their partitioning behavior between mobile liquid phase and the stationary phase
Principle of Separation in Chromatography
Adsorption chromatography
• Separation is mainly based on differences between the adsorption affinities of sample components and surface of active solid
• Probably one of the oldest types of chromatography
• Utilized a mobile liquid or gaseous phase that is adsorbed onto the surface of a stationary solid phase. The equilibration between the mobile and stationary phase accounts to the separation of different solutes
Adsorption chromatography
• Pada proses adsorpsi : molekul solut dan solven berkompetisi memperebutkan sisi aktif (site) dari adsorben (fase diam) teradsorpsi
• Gaya penarikan : - dipole-dipole
- dipole - induced dipole
- gaya London
- kombinasi
Adsorben polar (silika / alumina )
• akan menahan komponen polar dan sebaliknya
• molekul yang mempunyai gugus fungsional polar mempunyai afinitas kuat
• molekul “polarisable” (seperti aromatik)
interaksi dipole / induced dipole akan tertahan
Adsorben nonpolar (arang aktif)
• Gaya London ( dispersi )
• Senyawa nonpolar tertahan >
Pada permukaan adsorben terdapat “site” adsorpsi,
untuk silika gugus hidroksilnya (OH) - Si – OH (gugus silanol)
2 ( Si - OH ) Si - O - Si + H2O
1st Lesson
Principle of Separation in Chromatography
Partition chromatography
• Gas chromatography is mainly based on differences between the solubility of sample components in stationary phase
• Liquid chromatography is on differences between the solubility of sample components in mobile and stationary phases
• The form of chromatography is based on a thin film formed on the surface of a solid support (a liquid stationary phase); Solute equilibrates between mobile phase and stationary liquid
Partition chromatography
• Adsorben padat digantikan dengan fase diam cair
• Fase diam dilapiskan pada padatan pendukung
(biasanya padatan bersilika)
• Banyak digunakan pada GLC
o fase diam tidak larut pada fase bergerak
(gas)
o tidak terbawa oleh fase bergerak karena
adanya gaya gesek (shear force).
Sedang diterjemahkan, harap tunggu..