- Nessler cylinder
Nessler cylinders are laboratory tubes with a fixed volume. On the walls there are marks of the nominal stroke volume (usually 100 cc) and possibly one half-way mark (then usually 50 cc.)
Nessler cylinders are used for colorimetric analysis. The color of the substance contained in a Nessler cylinder visually compared with the model. The tubes are often used to carry out a series of calibration solutions of increasing concentrations, which functions as a comparative scale. To minimize differences in the subjective impression of the color of the solution of the substance to be analyzed, cylinders of a series should have the same characteristics - height, diameter and thickness of glass. Basically there are three types of used cylinders:
- high with a capacity of 100 cc (about 375 mm in height, around 1920 to 1924 mm in diameter)
- low capacity of 100 cc (about 210 mm in height, approximately 1930 to 1934 mm in diameter)
- ow capacity of 50 cc (about 300 mm in height, approximately 1917 to 1921 mm in diameter).
These parameters (except volume), however, can vary significantly between two cylinders.
Cylinder Nessler are similar Hehnera cylinders. They differ in that they are scaled to full height, while the bottom to the tap through which the solution is dropped.
Currently, due to the spread of automated spectrophotometers colorimetric assay methods using Nessler cylinder and visual assessment are used very rarely. Nessler cylinders are still used, however, in such a way as a test tube or reaction vessel.
- Witold Hermanowicz, Vera Dożańska, John Dojlido, Bohdan Koziorowski: Physico-chemical examination of water and wastewater. New York: Arcade, 1976, pp 19-21. UKD 628.31:628.1.03:543.3.
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