In the laboratory, there are many different kinds of tools. Each tool has its shape and purpose, and a burette is one example.
A burette is a laboratory equipment that is usually used in titration experiments to measure the amount of a chemical. The burette is made of glass and looks like a long tube with lines that show volume and a stopper or stopcock at the bottom.
Drops of several liquid reagents can be kept in the stopcock. In titration experiments, you need to be very accurate and careful. The number of droplets is meant to be the right size.
Check out the explanation below to learn more about what a burette does and how to use it correctly.
Burette Function
In general, a burette is used to drip several liquid reagents when doing experiments, especially titrations. Compared to measuring cups or drop pipettes, burettes are the most accurate.
The volume marker on a burette starts at zero at the top and goes up as you go down to the bottom.
The maximum volume that can be measured with a standard-sized laboratory burette is 50 mL. For marking, the volume is placed in precise 0.1 mL steps.
The volume can be read to the first decimal place, and then the second decimal place can be estimated.
Types of Burettes
Based on Designation
Based on what they are used for, burettes can be divided into the following groups:
1. Acid Burette
A burette made of a glass spout specialized for acidic solutions, such as HCl, NHO3, oxidizing solution (KCrO4), and neutral solutions such as thiosulfate.
2. Base Burette
The base burette has a glass ball on the end of the rubber spout that acts as a faucet. Alkaline solutions, like NaOH, KOH, and so on, are the only ones that can be used.
3. Universal Burette
Universal burettes are used for all kinds of solutions, whether they are acidic, basic, or neutral. Most of the time, the universal burette tip spout is made of Teflon.
4. Amber Glass Burette
An Amber glass burette is a type of burette that is made of glass that is brown or dark in color. This burette is made for chemical solutions like potassium permanganate and iodine that are easily oxidized by sunlight.
5. Classic Burette
For different versions, this burette is also called a Hempel burette, a Winkler burette, a Bunte, or a Tutweiler.
This burette works when the sample is measured and the gas is moved from the leveling vessel to the absorption solution with the help of the binding fluid.
At the top, there is a stopcock or tap that lets one of the absorption pipettes connect to the outside air.
6. Digital Burette
This burette is like a syringe in shape. The plunger is made of polyethylene or plastic, and the barrel is made of glass. This is done so that the liquid, including the alkaline solution, doesn’t eat away at the glass.
Later, the volume is shown on a digital screen, and the syringe is used to give very precise aliquots. A computer can also be used to control this burette.
Based on Capacity and Accuracy
In addition, when viewed from the level of accuracy, burettes can also be divided into several types, including:
- Micro-Burette
Micro burette is a burette that has a volume capacity of about 50 mL with an estimated scale level of uncertainty reaching 0.10 mL.
- Semi-Micro Burette
A semi-micro burette is a burette that has a volume capacity of about 25 mL and the smallest scale of uncertainty or estimation that can be read is 0.050 mL.
- Macro Burette
A macro burette is a burette that has a capacity of up to 10 mL and an uncertainty estimation scale of about 0.020 mL.
How To Use A Burette
- Make sure first whether the burette to be used is clean, and free of microorganisms, or other chemical objects. Also, make sure that the burette is dry.
- If the burette is considered clean, the next step is to install the burette on a stative and clamp or special burette pole. The burette must be in a straight condition, not tilted and tightly attached to the stative. The state of the tap or stopcock must be in a tightly closed position.
- Position the burette on a flat, level surface and in a low place to make it easier to put the chemical solution into the burette later.
- Put the titrant solution into the burette using the help of a laboratory funnel. Do not let the titrant solution exceed the maximum meniscus line of the burette or the zero point. Entering the titrant solution should be done in a low place or not on the laboratory table. This is to prevent the titrant solution from spilling onto the body or other areas in the laboratory.
- Once the burette is filled with the titrant solution, move the burette back on the laboratory table and make sure to calibrate the titrant volume until it is right on the meniscus line.
- The burette is ready to be used for the titration trial.
That was the explanation of the burette along with its functions and how to use it. Hopefully, the above information can be helpful and increase knowledge, especially in understanding laboratory equipment.