Question

explain how to prepare sample solutions and capillary applicators

Answer 1

Prepare , a solution of known concentration is perhaps the most common activity in any analytical lab. The method for measuring out the solute and solvent depend on the desired concentration unit and how exact the solution’s concentration needs to be known. Pipets and volumetric flasks are used when a solution’s concentration must be exact; graduated cylinders, beakers and reagent bottles suffice when concentrations need only be approximate. Two methods for preparing solutions are described in this section.

Capillary applicators , are very useful for depositing small amounts of sample onto a TLC (thin layer chromatography) plate. This prevents overloading and helps achieve an accurate and clear TLC in preparation for running a full column. TLC spotters are easy to make and are a much better alternative to trying to use a Pasteur pipette which have a wider opening and so create a larger spot on the TLC – no matter how careful you are.

TLC spotters are made from glass capillary tubes, available from most suppliers of chemicals or glassware. A capillary tube with two open ends will create two TLC spotters. A capillary melting point tube – with one end closed – will create one TLC spotter