Autenrieth Colorimeter

AUTENRIETH COLORIMETER (Autenrieth), one of the types of colorimeters (see), very convenient for analytical and clinical work. Its principle: the color of the test liquid poured into a glass cuvette is compared with the color of the standard liquid, poured into a glass wedge. By moving the latter up and down by means of a rack, a layer of 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 the scale. The wedge is pre-calibrated by pouring into the cuvette a series of solutions of the substance being sought of different, precisely known concentration. The scale readings obtained are plotted on coordinate paper against the corresponding concentrations, at which points should lie on one straight line. From the graph thus obtained, the content of the substance being sought is found for any division of the scale. The A. k. has found wide application in clinical and experimental laboratories, as it is very simple to use and requires small amounts of test material (2-3 cubic cm). Among the numerous methods in which the A. k. can be used, the most important are: determination of sugar by Folin's method, uric acid, cholesterol, phosphorus, hemoglobin, iron, nitrous acid in water, nitrogen (Nesslerization), creatinine, bilirubin, and many others. The accuracy of determinations made with the aid of the A. k. is within 2-5%, i.e., quite sufficient for most biological work.

It is manufactured by the firm Hellige, Freiburg; without wedge - 35 marks; spare empty wedge - 8 marks; wedge with standard liquid, calibrated - 18 marks (price list 1927).