Microscale – Column chromatography (CC)

The purification of a substance by microscale column chromatography (CC) can be performed in two ways. Either by using a column adapted to the amount of substance to be purified, or by means of a Pasteur pipette prepared for this purpose with a silica gel or alumina packing.   Kontes-Williamson equipment has microscale column chromatography … Read more

Microscale – Sublimation

What is microscale sublimation? Sublimation consists of the evaporation of a solid from a hot surface and its subsequent condensation on another surface at a lower temperature. Depending on the nature of the solid, sublimation can occur at atmospheric pressure or under vacuum. It is a very effective technique for the purification of solids at … Read more

Microscale – Removal of small amounts of solvents

What is microscale removal of small amounts of solvents? The usual way to remove a solvent is with a rotary evaporator. A solvent can be removed under reduced pressure using round-bottom flask with ground-glass joints of a suitable volume (e.g. 5 ml or 10 ml). However, there are other alternatives: By gas stream. The vessel … Read more

Microscale – Removal of harmful vapors

What is removal of harmful vapors? As in mini-scale processes, it is sometimes necessary to remove harmful or hazardous vapors generated in a reaction in a controlled manner. The following figure shows the assemblies that are usually used for this purpose. Note the absolute parallelism of these setups with those described in basic laboratory operations. … Read more

Microscale – Reflux

What is microscale reflux? Different configurations are available to perform a reaction under reflux at the microscale. With Kontes-Williamson equipment, the reaction tubes can be used directly. Since the solvent volume is very small, the vapors rise along the tube, cool on the wall and fall back to the bottom of the tube, thus establishing … Read more

Microscale – Recrystallization in a Craig tube

What is recrystallization in a Craig tube? The Craig tube consists of two separable parts, an inner and an outer part. The outer part is similar to a test tube with rough ground glass in the widening tube neck. The plunger is usually made of Teflon or glass (in the latter case ground glass). Both … Read more

Mass and volume measurements

One of the first aspects to be solved is the availability of electronic balances that allow weighing quantities within the required range. For weighing solids, the micro-spatula and weighing boats of the appropriate size for the order of magnitude of the substances employed. As for the measurement of volumes, pipettes (drain-out or blow-out), automatic pipettes … Read more

Microscale – Liquid-liquid extraction in conical vials

What is liquid-liquid extraction in conical vials? Microscale liquid-liquid extraction can be efficiently performed with a conical vial. The two phases are introduced into the conical vial, closed with the corresponding screw cap and the mixture is shaken vigorously for a couple of minutes. The stopper is opened and the two phases are allowed to … Read more

Mircoscale – Inert atmosphere reactions

Reactions under inert atmosphere can be carried out at microscale in a similar way to miniscale reactions. A first possibility is to perform them under a stream of nitrogen, when a centralized gas system is available, or a gas cylinder to which a Teflon or silicone tube is connected with a syringe without the plunger … Read more

Microscale – Filtration

What is microscale filtration? The two most common ways to filter a solid at microscale are as follows: With the aid of a Pasteur pipette If you want to remove the supernatant liquid from a solid in a vessel (vial, Erlenmeyer, etc.) you can use a Pasteur pipette. The pipette, provided with a teat, is … Read more