Farbmetrische

Farbmetrische refers to a family of analytical methods that quantify chemical species by measuring color changes or color intensity in a sample. The term, rooted in German as Farb- (color) and metrische (measurement), is used in German-language scientific literature to describe colorimetric analyses and related techniques. In these methods, a specific chemical reaction or binding event produces a colored product, the intensity of which correlates with the concentration of the target analyte within a defined range.

Principles and measurement are typically based on the relationship between color and concentration. The sample is exposed to reagents that yield a colored species, and the resulting color is measured with optical instruments such as colorimeters or spectrophotometers. The measured absorbance or reflectance is related to concentration through calibration curves and, in many cases, the Beer–Lambert law. Modern approaches extend to digital image analysis and smartphone-based colorimetry, where color values extracted from images are converted into quantitative results.

Techniques and instrumentation used in Farbmetrische work include solution- and paper-based colorimetric assays, microplate formats, and field-portable test strips. Paper-based analytical devices and sensor arrays have expanded the reach of colorimetric measurements to point-of-care testing, environmental monitoring, and food safety.

Applications and limitations: Farbmetrische methods are valued for simplicity, rapidity, and low cost, making them well suited for routine screening and field work. Limitations include interference from sample color or turbidity, reagent stability, and limited sensitivity compared to instrumental methods. Accurate results rely on careful calibration, proper blanking, and consideration of matrix effects.

See also: colorimetry, spectrophotometry, Beer–Lambert law.