Quality control methods for

21. Specifications for adsorbents for use in thin-layer 
chromatography 
Cellulose 
Description. A fine, white, homogeneous powder with an average particle size of 
less than 30 pm. 
Preparation. Suspend 15 g in 100 ml of water and homogenize for 60 seconds in 
an electric mixer. Carefully coat cleaned plates with a layer 0.25 mm thick using 
a spreading device. Allow the coated plates to dry in air. 
Separating power. Apply separately to the adsorbent layer 10 µl of 0.25 mg/ml 
solutions containing respectively brilliant black BN R, amaranth S R, fast yellow 
AB R and tropaeolin O R in a mixture of equal volumes of methanol R and 
water. Develop the plate using a mixture of 50 volumes of 1-propanol R, 10 
volumes of ethyl acetate R and 40 volumes of water over a distance of 10 cm. 
The chromatogram shows four clearly separated spots. 
Cellulose, microcrystalline 
Description. A fine, white, homogeneous powder with an average particle size of 
less than 30 gm. 
Preparation. Suspend 25 g in 90 ml of water and homogenize for 60 seconds in an 
electric mixer. Carefully coat cleaned plates with a layer 0.25 mm thick using a 
spreading device. Allow the coated plates to dry in air. 
Separating power. Apply separately to the adsorbent layer 10 µl of 0.25 mg/ml 
solutions containing respectively brilliant black BN R, amaranth S R, fast yellow 
R and tropaeolin O R in a mixture of equal volumes of methanol R and water. 
Develop the plate using a mixture of 50 volumes of 1-propanol R, 10 volumes of 
ethyl acetate R and 40 volumes of water over a distance of 10cm. The 
chromatogram shows four clearly separated spots. 
Cellulose F
254
 
Description. A fine, white, homogeneous powder with an average particle size of 
less than 30 µm containing a fluorescent indicator with an optimal intensity at 
254 nm. 
Preparation. Suspend 25 g in 100 ml of water and homogenize for 60 seconds 
using an electric mixer. Carefully coat cleaned plates with a layer 0.25 mm thick 
using a spreading device. Allow the coated plates to dry in air. 
Separating power. Apply separately to the adsorbent layer 10 µl of 0.25 mg/ml 
solutions containing respectively brilliant black BN R, amaranth S R, fast yellow 
R and tropaeolin O R in a mixture of equal volumes of methanol R and water. 
Develop the plate using a mixture of 50 volumes of 1-propanol R, 10 volumes of 
ethyl acetate R and 40 volumes of water over a distance of 10cm. The 
chromatogram shows four clearly separated spots. 

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Quality control methods for medicinal plant materials 
Fluorescence. Prepare a 1.0 mg/ml solution of benzoic acid R in a mixture of 9 
volumes of 2-propanol R and 1 volume of formic acid (~1080 g/l) TS. Apply to 
the adsorbent layer at 10 points of application, increasing the quantities of the 
solution from 1 µl to 10 µl. Develop the chromatogram using a mixture of 9 
volumes of 2-propanol R and 1 volume of formic acid (~1080 g/l) TS. Allow the 
solvents to evaporate and examine the chromatogram in ultraviolet light at 254 
nm. The benzoic acid appears as dark spots on a fluorescent background in the 
upper third of the chromatogram for amounts of 2 µg and more.