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titrators-burettes
Burettes are glass tubes with a scale and a stopcock at the lower end. They are used in laboratories to measure small amounts of liquid. There is a scale on the front and often a stripe on the back, typically white with a blue line, aiding in more precise readings and avoiding parallax errors. All burettes are calibrated to zero (on EX), meaning the scale reading difference indicates the volume of liquid dispensed, excluding any liquid clinging to the glass wall.
Glass burettes come in clear glass, clear glass with Schellbach stripe, or amber glass designs. The stopcock can be positioned directly under the glass tube or on the side, available with a cock, Teflon or glass stopcocks, as a pinch or valve stopcock.
Simple burettes are filled from the top. More convenient are filling burettes, which can be directly attached to a reservoir bottle with standard solution (Pellet titration apparatus). The liquid is pumped through a glass tube into the burette, with an automatic zero adjustment. Excess liquid flows back into the reservoir bottle. Burettes are classified into different accuracy classes, with class AS being the most precise.
Digital burettes
Digital burettes screw directly onto the reservoir bottle. They have a piston filled with solution through mechanical means. A valve prevents solution from returning to the reservoir bottle. The piston moves automatically to fill the burette. This dosing is very precise due to exact control over the amount. Large piston burettes are used to fill burettes from a reservoir bottle.
During titration a standard solution (acid/base) is dripped into a sample solution (base/acid) of unknown concentration until the solution is neutral. At the equivalence point, the amount of standard solution used corresponds to the concentration of the sample solution.
In automatic titration, the sample solution is mixed with the standard solution through a tubing system. A computer calculates the pH value and determines the equivalence point.
Varieties of burettes in the range:
- Glass burettes
- Titration apparatus
- Digital burettes
- Automatic titrators
Burette manufacturers:
- Brand
- Bürkle
- Hirschmann
- methrom
- SI Analytics
- Vitlab
- LLG
- ISOLAB