Spreading device

The introduction of the sample valve, however, helped establish radial equilibrium early in the separation but, unless some special sample spreading device is employed at the front of the column, equilibrium will not necessarily occur at the point of injection. The stream splitting process is depicted in Figure 2. 

Spreader A suitable spreading device that, when moved over the glass plate, applies a uniform layer of adsorbent of the desired thickness over the entire surface of the plate. 

In TLC a commercial spreading device is usually used to prepare the adsorbent bed [e.g.. Refs. (2,3)]. Many laboratories have dispensed with this aspect of separation, however, since commercially prepared plates are now available for the commonly used adsorbents. The preparation of plates with an adsorbent gradient (Section 2-5F) requires special equipment [e.g.. Ref. ( )]. 

Research institute Spreading device Powder coating unit Stabilising unit... 

Pick-up roll—A spreading device where the roll for picking up the adhesive runs in a reservoir of adhesive. 

Previous editions of this book contained discussions of three commercial layer-spreading devices, preparation of gradient layers (Stahl and Mueller, 1980), and manual layer preparation by pouring, spraying, and dipping. These will not be repeated here. 

Pick-up Roll n (1) In the coil coating industry, the roll which revolves within the pan and is partially immersed in the paint. This roll picks up paint from the pan and applies it to the transfer or applicator roll. (2) Spreading device where the roll for picking up the adhesive runs in a reservoir of adhesive. 

Thin-layer spreading device Thin-layer chromatography plates Thin-layer chromatography tank Spray hottle 2 ml graduated flasks 100 ml separating funnels... 

To prepare five plates, each 20 cm x20 cm, shake 98 g of Kieselgel G (Merck No.7731) with 165 ml of distilled water for about 90 seconds until a creamy slurry of even consistency is obtained. Pour the slurry into the spreading device and coat the plates... 

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