Silica Gel F₂₅₄

A fine, white, homogeneous powder of an average particle size of about 15 µm containing a suitable binding agent and about 1.5% of a florescent indicator having a maximum intensity at 254 nm. It complies with the following requirement.

Fluorescence Carry out the method for thin-layer chromatography using a mixture of 10 volumes of anhydrous formic acid and 90 volumes of propan-2-ol as the mobile phase, but allowing the solvent front to ascend 10 cm above the line of application. Apply separately to the plate 10 quantities from 1 to 10 uL of a 0.1% w/v solution of benzoic acid in the mobile phase. After removal of the plate, dry it in a current of warm air and examine under ultraviolet light (254 nm). The benzoic acid appears as dark spots on a fluorescent background in the upper third of the chromatogram at levels of 2 µg and greater.