Autenrieth Colorimeter

AUTENRIETH COLORIMETER (Autenrieth), one of the types of colorimeters (see), very convenient for analytical and clinical work. Its principle is: the color of the test liquid poured into a glass cuvette is compared with the color of a standard liquid,

poured into a glass wedge. By moving the latter up and down by means of a rack and pinion, a layer of the colored standard liquid of varying thickness is brought into the field of view until its color matches the color of the test liquid. The position of the glass wedge is determined by a scale. The wedge is preliminarily calibrated by pouring a series of solutions of the substance in question of various, precisely known concentrations successively into the cuvette. The resulting scale readings are plotted on coordinate paper against the corresponding concentrations, and the points must lie on a single straight line. From the graph thus obtained, the content of the substance in question is found for any scale division. The Autenrieth colorimeter has found wide application in clinical and experimental laboratories because it is very simple to handle and requires small amounts of test material (2-3 cubic centimeters). Of the numerous methods in which the Autenrieth colorimeter can be used, the most important are: determination of sugar by Folin, uric acid, cholesterol, phosphorus, hemoglobin, iron, nitrous acid in water, nitrogen (Nesslerization), creatinine, bilirubin, and many others. The accuracy of determinations made using the Autenrieth colorimeter lies within 2-5%, that is, quite sufficient for most biological work.

Manufactured by Hellige, Freiburg; price without wedge 35 marks; spare empty wedge 8 marks; wedge with standard liquid, calibrated 18 marks (1927 pricing).