Precise & Protective

Archive for January, 2015

How to Operate the Centrifuge Tubes: Guidelines

The centrifuge tubes are cylinder shaped calibrated glass containers commonly used for the analysis and separation of various materials in the laboratory (centrifugation procedures). They needed to be fit into the centrifuge slots for the experiments.

microcentrifuge tubes

Centrifuge Tubes

These are used to test solid-liquid or immiscible liquid samples by the lab technicians. First, they deposit various substances into the centrifuge tubes and then they secure them into the centrifuge within the slots. For the rotation, the lab technicians spin the tubes at proper speeds until the denser particles in each substance gather at the point farthest from the axis and vice-versa.

Materials used

A wide range of laboratory centrifuge tubes are available in plastic, copolymers, polypropylene and polystyrene.

Sizes

It ranges from micro-centrifuge tubes with caps to larger tubes capable of 50,000 grams in refrigerated centrifuges.

Types

There are different types of centrifuge tubes widely used for different purposes such as:-

Micro Centrifuge Tubes

Microcentrifuge Tubes with Snap Cap

  • Conical Bottom Tubes
  • Microcentrifuge Tubes- Snap Cap
  • Microcentrifuge Tubes- Screw Cap and so on

How to use a centrifuge to avoid mishaps

There are few key guidelines for operating a centrifuge tube in order to prevent damage to the centrifuge and possible serious injuries to the lab doctors or technicians:-

  • Always work on an even surface, don’t use the centrifuge on an uneven surface or a slanted one. The surface should be properly leveled and firm.
  • It is safe to balance the centrifuge tubes in the rotor, say for- if you want to run a centrifuge tube with 20 mL of liquid, it is smart to put another tube with 20 mL of water in the opposing hole on the rotor. And if the liquid has a varying density than water, then the best possible way is to balance the tubes by mass not volume.
  • Never ever, open the lid while the rotor is moving. It can be really dangerous at times. Although, there are many centrifuges that come with a “safety shutoff” if the lid is opened but it only stops the power of the rotor. The rotor will still spin due to its own inertia and thus it is better to be careful at the first place.
  • While the rotation of the centrifuge tubes, a little vibration is normal but excessive wobbling can mean danger. Always, double check whether the tubes are correctly balanced or not. Do not take the risk to continue running a centrifuge that is shaking or wobbling while the rotor is spinning.
  • If you are in a laboratory, it is always preferable to wear a face shield or safety glasses. And if you are working near a centrifuge then it is a must.
  • Do not touch, bump or move the centrifuge while the rotor is still spinning.
  • It is better to clean the rotor and centrifuge well after each use to avoid further disruptions.
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How to use the Micropipette Tips

Pipettes are a common sight in any chemistry, biology or a physics laboratory. Popularly known as pipette, pipettor, chemical dropper or a pipet, it is a common laboratory tool to transfer a measured volume of liquid. They are available in different designs for different purposes.

High Quality Micropipette Tips

Micropipette Tips Sizes

Micropipettes are those dispensing between 1 and 1000 μl and in contrast, macropipettes dispense greater volumes. Depending upon the sizes, capacity and style, pipettes is of following types:

•    Air displacement micropipettes
•    Positive displacement pipette
•    Volumetric pipettes
•    Graduated pipettes
•    Pasteur pipette
•    Transfer pipettes
•    Van Slyke pipette
•    Ostwald–Folin pipette
•    Glass micropipette
•    Extremely low volume pipettes
•    Microfluidic pipette

Micro Pipettes

Laboratory Micropipettes

But before using a pipette, it is extremely necessary that you master their use in order to be successful in the lab experiments.

Parts of Micropipette

a)    Plunger button
b)    Tip ejector button
c)    Volume adjustment dial
d)    Digital volume indicator
e)    Shaft
f)    Attachment point for a disposable tip

Sizes of micropipette

Basically, micropipettes come in three different sizes of varying capacity. They are P20, P200 and P1000. The sizes are noted on the top of the plunger button (as mentioned earlier, part a)

Pipette Tips

You should always remember that liquids are never drawn directly into the shaft of the pipette. For this, a disposable plastic tips are attached to the shaft and for adjusting the volume of the liquid, there is a black volume adjustment dial near the top of the micropipette.

There are two sizes of tips. The larger blue tips are used for the P1000 and the smaller clear tips are used for the P20 and P200. You should also take care of not contaminating the tips, for example: – close the box of the tips (racked in), after the use so that airborne contamination can be prevented.

How to insert a tip

Micropipette tips uses

Micropipette tips function

Before inserting a tip, you should keep some essential points in mind as given below:-
•    Select the correct size tips.
•    Open the box without touching the tips with your hands.
•    Insert the micropipette shaft into the tip and press down firmly. This will attach the tip to the shaft.
•    Remove the micropipette, with the tip attached.
•    Close the box without touching the tips with your hands
•    Remember, it is better to handle something carefully rather than doing it like a defaulter.