Burettes, Laboratory Glassware

Definition:

A burette is a uniform-bore glass tube with fine graduations and a stopcock at the bottom. It is used in volumetric analysis to measure the volume of a liquid, especially of one of the reagents in a titration. Burettes are used when it is necessary to dispense a small measured volume of a liquid, as for titration. Burettes may be used to calibrate the volumes of other pieces of glassware, such as graduated cylinders. Most burettes are made of borosilicate glass with PTFE (Teflon) stopcocks. Burettes are extremely accurate - a 50 cm3 burette has a tolerance of 0.1 cm3 (class B) or 0.06 cm3 (class A).The name Of apparatus used to hold burette is dropper clip.

Types of burettes:

1. Acid burette

2. Base burette

Difference between the both burette is that ACID burette can only take acid,and BASE burette can only take base.

Procedure:

Burettes measure from the top since they are used to measure liquids dispensed out the bottom. The difference between starting and final volume is the amount dispensed Also used for buretting are buretting syringes. These are calibrated to Volumetric A grade tolerances which are equal to or better than the traditional burette tolerance. The graduated buretting tube is provided with a thumb operated piston and PTFE seal which slide within the tube in a positive displacement operation. This arrangement is provided to achieve improvements in reliability, by removing problems of bubble entrapment while filling, leaks and blockages in stopcock mechanisms. The design also addresses handling safety, economy, and versatility when handling volumes between 0.5 and 25mL. The buretting syringe is set up in a traditional burette holder or used freehand. The positive displacement action enables it to handle any laboratory fluid - viscous and volatile, hydrocarbons, essential oils and mixtures, with great accuracy. Other features of the buretting syringe are the provision of a red line on the sliding seal which may be read instead of the meniscus, thus virtually eliminating parallax error, and its robust form which makes it more resistant to breakage and easier to clean.

Uses:

1. It is used to to dispense a small measured volume of a liquid.
2. It is used for measuring liquid.
3. It is commonly used in titration.
4. It is used especially in laboratory procedures for accurate fluid dispensing and measurement.

Some burette manufacturers in India are:

1. Kshitij Innovations
2. Labtech International
3. Labtech International
4. Nexus Enterprises
5. Naugra Exports
6. Popular scientific

Reference sites:

Science Equipment for a Molecular Biology Laboratory

To start with, when you begin equipping a molecular biology lab, you need the usual test tubes, beakers, desiccators, pipettes with fillers, and flasks, together with all the necessary clamps, stoppers, frames and supports.

The basic furniture will need to consist of sufficient worktop space, computer station/s, chemical and biological storage cabinets, possibly a filtered, controlled environment (heating & cooling, and humidity control). In some cases access control, a gray room and clean room conditions may even be necessary.

Since this branch of science deals with organic materials from living cell tissues, it stands to reason that temperatures are critical. Most laboratories use refrigerators and freezers, and sometimes surface mounted refrigeration units. Some procedures may require temperatures to be reduced to as low as -86A deg. C.

Centrifuges and microcentrifuges may need to stand on refrigerated and unrefrigerated tabletops for different purposes.

The heating devices may include a microwave, Bunsen burners, and/or hot plates.

There are a number of calibrated and measurement devices, apart from the glassware, that will be needed in a laboratory, such as certain plastic ware, micro balances and scales, pH meters, moisture meters and thermometers.

Microscopes or electron microscopes appropriate to the research being done, together with camera port and link to computer. These are a part of every laboratory.

There is a large number of apparatus and equipment generally considered essential for a molecular biology laboratory. Tissue processing for DNA identification is often an important part of molecular biology and many processes require the equipment for this, depending on the extent of DNA study and genomics. Here is some of the general apparatus likely to be needed:

* CO2 incubator for cell cultures.
* Vacuum pumps.
* Liquid nitrogen tank.
* Water bath.
* Magnetic stirrer.
* Spectrophotometer.
* Chromatograph.
* Vortex rotators and platform shakers.
* Autoclaves and sterilizers.
* Electrophoresis chamber and gel casting and documentation chamber.
* UV Transilluminator.
* Gradient and standard thermocycler to amplify segments of DNA.

Then we come to the question of safety and protection of the environment and of the people who work in the laboratory; and most of the following will normally be necessary:
Clothing such as:

* Aprons and lab coats.
* Coveralls.
* Footwear, such as shoe covers.
* Head covers, bouffant caps and face covers, masks.

Gloves:

* Heavy weight latex gloves.
* Thin, disposable latex gloves.
* Nitrile gloves.
* Cotton gloves.
* Vinyl gloves.

For eye protection there is a great variety of safety glasses, clear and tinted for lazer and UV work, as well as masks and face shields with and without respirators for protection against splashing, fumes and gasses and flying objects. It is important in a laboratory to install an eyewash station for emergencies.

Last but not least is all the equipment needed for cleaning and sterilizing the glassware, apparatus and even the clothing and furniture used in the laboratory. The cleaning of these items is not always straight forward, and some special procedures need to be followed. You need to have specially designed scrubbers and brushes as well as suitable cleaning fluids and preparations, among other things.