Different Types of Laboratory PipettesVolumetric Pipettes

These instruments allow the user to measure the volume contained with incredibly accurately. These are often found in both commercial laboratories as well as university labs. They come in a number of different sizes depending on how much fluid you’re looking to extract and measure. These lab devices usually have a capacity ranging between 1 and 150ml. Micropipettes

These micropipettes differ from volumetric pipettes in that they need to be calibrated in order obtain incredibly accurate results. These need to be calibrated every few months in fact. However, if labs use them more frequently, they’ll need to be calibrated more frequently from application to application. Measuring Pipettes

These lab tools are usually not as accurate as their micro and volumetric cousins. They have marked hash lines along the side of the shaft so that the user can ascertain how much liquid is contained within the pipette. They are also able to measure multiple amounts of liquid at once because of these hash lines. As stated earlier though, they’re often not as accurate as the aforementioned pipettes. Mohr and Serological Pipettes

The main difference between these two types of measuring pipettes is the hash marks on the side of the shaft. Mohr pipettes’ hash marks always end before the tip whereas Serological pipettes have marks that continue all the way down to the tip. Other variations of these include blow-out pipettes. These essentially allow the user to blow out any excess residue left in the shaft.why is the meniscus viewed at eye level

To be sure you are able to read consistently and accurately, always read the meniscus at eye level.When the eyes are above the level of the meniscus, the value read is less than the level reading.When the eyes are below the level of the meniscus, the value read is more than the level reading.Your eyes should be at the same level as the meniscus when taking a reading.

Pipet Safety

1. Do not ever use your mouth to pull the liquid into a pipet. This is the most common method of becoming poisoned in a chemical laboratory or becoming infected in a clinical laboratory. Mouth pipetting is forbidden in the chemistry department. 

2. Do not allow the solution to be drawn up into the bulb. This will result in chemicals getting on top of the pipet where you must put your finger.

3. Do not insert the pipet into the hole in the bulb. You might break the pipet and cut yourself while trying to insert it. Also, having the bulb attached to the pipet increases the risk of drawing the solution into the bulb. 

How Pipettes Work

The calibrated-glass pipette has helped form many opinions about today’s mechanical pipetting devices. Glass pipettes have no moving parts. They have two operational states—fully functional or broken. If a glass pipette is cracked or chipped, or a bubble is drawn into it, the problem is readily evident to the user. In addition, accuracy and precision are largely independent of technique.