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Posts tagged ‘Buret’

Laboratory Glassware – A Primer Part 4

Continuing from Part 3

We’ve covered most of the basic items one would find in a laboratory, but now it is time to cover some of the more obscure pieces one might find:

Separatory Funnel: Most folks understand what a funneldoes. But a

Separatory Funnel

separatory funnel has a slightly different purpose. It is designed to flow liquid (sometimes solids) down a small tube. The flow is controlled with a stopcock. The main purpose of a separatory funnel is so that liquids of different density can separate in the funnel. The more dense liquids will move towards the bottom and the lighter liquids will stay on top. This allows the labworker to draw off the denser liquid without losing much of the lighter liquid. Some special designs of separatory funnels have a draining system at their top so that the lighter liquid can be drawn off first. Separatory funnels are usually glass but many plastic versions exist for economical use when the liquids are not hot.

Centrifuge Tubes: Centrifuge tubes are used, as one may expect, in a centrifuge. These tubes are designed to

1.5ml Centrifuge Tube

fit into the centrifuge and be spun at high speeds. Typical sizes are 1.5ml, 15ml and 50ml although other sizes do exist.  Centrifuge tubes are almost always made of plastic due to the rigors of going through a centrifuge can break glass, and the difficulty with cleaning them puts them into the disposable category. Centrifuge tubes are very useful and get use for holding chemicals in other laboratory systems.

Pipets & Pipettors: Pipettes get shown a lot on TV forensic shows a lot for

Mechanical Pipettor

some reason. The idea behind a pipet or pipettor is to draw out very precise quantities of a chemical. Pipets are very accurate for this purpose, with graduation accuracy of up to 1/100 of a milliliter. Pipettors can get very advanced,  an example being mechanical pipettors that can be high accuracy or high volume. Mechanical Pipettors can get quite advanced, with systems of pippettors designed to take multiple samples and controlled via robotic arms.

Burets: While pipets draw in a precise amount of a chemical, buretsare


designed to dispense very accurate amounts of chemicals. Burets are usually held on support stands or other systems. They have a variety of dispensing systems for the chemicals, using either stopcocks or pinchcocks (where a glass ball bearing surrounded by rubber keeps the liquid in the buret until it is pinched by the lab technician. ) .




Will there be a Part 5 of this series? We’ll see! Be sure to leave us a comment!