Thin‐layer chromatography (TLC) is a simple and inexpensive analytical technique that can
quickly and efficiently separate quantities of less than ten micrograms of material. TLC is used for the
rapid analysis of reagent and product purity, or to quickly determine the number of compounds in a
mixture. Also, by comparing an unknown compound’s behavior to the behaviors of known standard
compounds. Also, TLC is often used for selecting a suitable solvent before attempting a larger scale
column chromatographic separation. In TLC, capillary action allows a liquid (mobile phase) to ascend a
solid (stationary phase) coated on a support plate. A sample of the compound mixture is applied near
the bottom of a dry TLC plate, as shown in Figure 1(a). The plate is placed into a developing chamber, a
covered container with a shallow layer of mobile phase liquid in the bottom. As the mobile phase
ascends the plate, the mixture compounds move along the plate to different extents, due to differences
in their relative attractions for the mobile and the stationary phase. After the separation is complete, the
TLC plate is called a chromatogram, as shown in Figure 1(b).
During the TLC process, the solid stationary phase, called the adsorbent, adsorbs the mixture
compounds. As the mobile phase or the eluent travels up over the adsorbent in different rate. A
reversible and continuous competitive attraction between the eluent and the adsorbent for the
mixture compounds causes this rate difference. Compounds with less attraction to the adsorbent
move rapidly with the eluent, whereas compounds with more attraction to the adsorbent move
slowly with the eluent. Because TLC adsorbents are typically very polar, the more polar is a
compound in the mixture, the more strongly it adheres to the adsorbent and the more slowly it
moves. Similarly, intermolecular attractions between the eluent and the compounds determine the
solubility of the compounds in the mobile phase. In general, the more polar the eluent, the more rapidly
a given compound moves. Polar compounds, which are strongly attracted to the adsorbent, require polar
eluents to attract them away from the adsorbent.
Thin‐layer chromatography (TLC) is a simple and inexpensive analytical technique that can
quickly and efficiently separate quantities of less than ten micrograms of material. TLC is used for the
rapid analysis of reagent and product purity, or to quickly determine the number of compounds in a
mixture. Also, by comparing an unknown compound’s behavior to the behaviors of known standard
compounds. Also, TLC is often used for selecting a suitable solvent before attempting a larger scale
column chromatographic separation. In TLC, capillary action allows a liquid (mobile phase) to ascend a
solid (stationary phase) coated on a support plate. A sample of the compound mixture is applied near
the bottom of a dry TLC plate, as shown in Figure 1(a). The plate is placed into a developing chamber, a
covered container with a shallow layer of mobile phase liquid in the bottom. As the mobile phase
ascends the plate, the mixture compounds move along the plate to different extents, due to differences
in their relative attractions for the mobile and the stationary phase. After the separation is complete, the
TLC plate is called a chromatogram, as shown in Figure 1(b).
During the TLC process, the solid stationary phase, called the adsorbent, adsorbs the mixture
compounds. As the mobile phase or the eluent travels up over the adsorbent in different rate. A
reversible and continuous competitive attraction between the eluent and the adsorbent for the
mixture compounds causes this rate difference. Compounds with less attraction to the adsorbent
move rapidly with the eluent, whereas compounds with more attraction to the adsorbent move
slowly with the eluent. Because TLC adsorbents are typically very polar, the more polar is a
compound in the mixture, the more strongly it adheres to the adsorbent and the more slowly it
moves. Similarly, intermolecular attractions between the eluent and the compounds determine the
solubility of the compounds in the mobile phase. In general, the more polar the eluent, the more rapidly
a given compound moves. Polar compounds, which are strongly attracted to the adsorbent, require polar
eluents to attract them away from the adsorbent.
การแปล กรุณารอสักครู่..
