Adsorbent Material

The adsorbent layer is usually silica gel but can also include aluminum oxide, Florisil, or modified silica like reversed-phase layers (C8, C18), amino, or cyano. Your choice depends on the compound you’re separating. Check past methods to guide your selection - it saves time and effort.

Plate Backing

Most plates have a glass backing for durability and compatibility with solvents. Flexible backing like aluminum is easier to cut for smaller sizes. Glass plates can also come pre-scored for convenience. The table below compare the glass and aluminum backings for TLC plates.

Properties	Glass	Aluminum
Appearance	Rigid and transparent	Flexible and opaque
Susceptible to breakage	Yes	No
Temperature stability	High	High
Weight and shelf space	High	Low
Can be cut with scissors	No	Yes
Binder stability in water	Depends on the plate type	Limited
Resistance against solvents	High	High
Resistance against mineral acids and conc. ammonia	High	Low

Layer Thickness

Thicker layers allow for sample recovery using scrapers or suction tools.

• • 100 - 200 μm: for high-performance HPTLC with better resolution
• • 200 - 250 μm: standard for analytical TLC plates
• • 500 - 2,000 μm: for preparative TLC to separate larger samples

Feature	Classical TLC	HPTLC	Preparative TLC
Application	General-purpose analytical separations	High-resolution separations for small samples	Separation and recovery of large sample quantities
Available backing	Aluminum & Glass	Glass	Glass
Cost	Cost-effective	Higher due to precision manufacturing	Higher due to large-scale applications
Layer thickness	200 μm (aluminum), 250 μm (glass)	100 - 200 μm	500 - 2,000 μm
Resolution	Moderate	High	Low to moderate
Sample Size	Small	Very small	Large
Sensitivity	Standard	Higher sensitivity due to thinner layers	Lower sensitivity due to thicker layers
Special features	Pre-adsorbent zones, fluorescent indicators	Narrow particle size distribution, high uniformity	Thick layers for sample recovery

Plate Size

Choose a size based on the number of samples and separation distance needed. Common sizes are:

• • Large size 20 x 20 cm: most popular size and cost-effective.
• • Smaller sizes: 10 × 10 cm, 5 × 10 cm, or 2.5 x 7.5 cm: are great for method development or fewer samples.

Plate Type

SepaFlash™ TLC plates are available with three (3) binder types, tailored for different applications:

• • Scored Plate
  Glass plates can be pre-scored for easy division into smaller pieces. A single plate can be spotted and split for development in different solvents or developed first, then divided for testing with various visualization techniques.
  • - 20 x 20 cm scored have three (3) score marks 5 cm apart (can be snapped to produce four (4) 5 x 20 cm plates).
  • - 10 x 20 cm scored have seven (7) score marks 2.5 cm apart (can be snapped to produce eight (8) 2.5 x 10 cm plates).
• • Preadsorbent Zone
  The non-reactive layer at the bottom of the plate compresses the sample into a narrow band before separation, enabling larger sample application, enhancing resolution, and allowing for less precise sample placement.
• • Channeled Plate
  Channeled plates have individual sample lanes separated by gaps in the adsorbent. These plates have 9 mm wide adsorbent tracks which are separated by 1 mm wide channels (total of 19 channels) where the adsorbent layer has been removed. This design prevents cross-contamination, making them ideal for precise analyses or legal documentation.

Fluorescent Indicator

Plates with a fluorescent indicator glow under UV light, enabling visualization of compounds that are invisible to the naked eye. This method preserves your compounds, making it ideal for preparative TLC.

• • UV254 (most popular): show dark spots where compounds absorb light at 254 nm.
• • UV366: may be needed for samples that fluoresce or require spraying with reagents for visibility.

Binder Type

SepaFlash™ TLC plates are available with three (3) binder types, tailored for different applications:

• • Soft Layer (Gypsum Binder)
  Calcium sulfate hemihydrate (CaSO₄•1/2 H₂O), or gypsum, provides strong adhesion to the glass backing and cohesive particle layers. These plates are compatible with sulfuric acid charring and organic solvents but are not recommended for systems with over 20 % water due to gypsum’s aqueous solubility. For higher water tolerance, hard layer plates are ideal.
• • Hard Layer (Organic Binder)
  An organic binder enhances durability, making these plates highly abrasion-resistant and compatible with solvents containing up to 80 % water. The hard layer surface is easy to write on, providing added convenience. This binder supports faster separations (25 - 30 % faster than standard plates) and yields compact, well-resolved spots. It is ideal for most visualization methods but is not recommended for vigorous stains like potassium permanganate (KMnO₄) and p-anisaldehyde.
• • Hard Layer (Inorganic Binder)
  These water-resistant plates are compatible with aqueous solvents, offering superior handling and sample application compared to gypsum binder plates. Their durable surface allows writing with a soft pencil. Hard layer plates with inorganic binders are ideal for applications requiring vigorous stains or avoiding organic binder interactions.

These binder options ensure versatility and reliable performance across diverse TLC applications.