Computador

UNIVERSIDAD ARTURO MICHELENA
FACULTAD DE CIENCIAS DE LA SALUD
ESCUELA DE PATOLOGÍA MEDICA
CARRERA DE CITOTECNOLOGÍA

THE PIPETTES

The pipettes are designed to transfer known volumes from onecontainer to another.The most common types of pipettes are:volumetric (capacity), the graduates and automatic.

• Volumetric pipettes: They are used to accurately measure asingle, fixed volume.These pipettes are for volumes from 0.5 mlto 200 ml.

• Graduated pipettes: Are calibrated in appropriate units to allowthe discharge of any amount less than its maximum capacity.The volumesrange from 0.1 to 25 ml.

The pipettes are filled with a gently suctioning bulb to about 2 cmabove the line gauge (instead of the bulb can be used a syringeor other suction device). During thefilling operation, the tip of the pipette should be kept submerged in the liquid. Then place theindex finger on top of the pipette and the solution is let out until the bottom of the meniscus with the linegauge.

Pipettes should be cleaned if the distilled water does not slideevenly across its walls, but adheres in the form of droplets on theinner surface. Cleaning can be done with a hot solutionofdetergent or cleaning solution

Once the liquid is poured, with a small volume in the pipette tipwhich has been calibrated to take into account, so should not be blown to remove this smallamount otherwise it is disturbed. Do not rely on split ends pipettes

The keys are made ​​of materials like glass, which is attacked by bases, and Teflon, an inert, resistant and highly advisable todissolve organic substances. In the case of using glass keys is not recommended to use a lubricant to ensure a good seal, because it would ruin the substance to be measured. A simpler type of key is thekey Bunsen, which is simply placing a glass bead firmly attached in a rubber tube. To deform the tube by a key, it passes the liquid.

Other sources of error are the drops that remain stuck at...