Silica Gel TLC Plates and H TLC Plates: What to Specify

When you order silica gel H TLC plates, the letters matter more than the plate size. The H grade carries no gypsum and no organic binder; the G grade contains about 13% gypsum as a binder; and the 254 in HF254 and GF254 marks a fluorescent layer that lights up yellow-green under UV at 254 nm so you can see spots that are otherwise invisible. Decide first whether you need a binder and whether you need fluorescence, then choose the layer thickness and the plate size that fit your tank and your sample.

What the Codes Mean

Our TLC silica gel is a white powder supplied in normal and high-efficiency grades, main component SiO₂·nH₂O. The four layer types in our range are:

• H — contains no gypsum and no organic binder. A pure silica layer, used where the binder would interfere with the separation or the detection.
• HF254 — no binder, plus an inorganic phosphor. It shows yellow-green fluorescence at UV 254 nm, so UV-absorbing spots appear as dark zones on a bright background.
• G — contains about 13% gypsum as a binder (calcined gypsum 12–14%) and is slightly acidic. The binder gives the layer mechanical strength.
• GF254 — gypsum binder plus the inorganic phosphor; fluoresces yellow-green at UV 254 nm.

All four types share the same chemical limits: chloride ≤ 0.02%, iron ≤ 0.02% and pH 6.0–7.0 in a 10% suspension, with "three colours separated" as the activity test.

Normal or High-Efficiency

The powder comes in two granularities: normal at 10–40 µm and high-efficiency at 3–10 µm. Finer particles give a tighter layer and sharper, better-resolved spots, which is what you want when two compounds run close together; normal granularity is the general round. State which one you need, because it changes the resolution the plate can deliver.

Pre-Coated Plates

If you would rather not prepare layers yourself, our TLC silica gel plates spray the same high-purity TLC silica gel powder onto a plate with a measured amount of binder. The surface is pure white, smooth and uniform, and the plates are supplied in the H, HF254, G and GF254 layer types. Standard sizes are 30×100, 50×100, 50×200, 100×200 and 200×200 mm; the activity test is again "three colours separated".

What to Specify When You Order

• Layer type — H, HF254, G or GF254.
• Form — loose powder, or pre-coated plate.
• Granularity — normal (10–40 µm) or high-efficiency (3–10 µm) for the powder.
• Plate size — one of the standard sizes above, for plates.
• Packaging — bottles and cartons for powder, or the boxed plate sizes.

The applications are the same across the range: qualitative or quantitative analysis of organic materials, identification of trace impurities and main components, and work in medicine, pesticides, Chinese herbal medicine, organic chemicals, grain and food analysis. For the preparative side rather than the analytical plate, see silica gel for column chromatography and flash column chromatography. Prices are quoted on request.