Vakiokäyrän

Vakiokäyrän, meaning "standard curve" in Finnish, is a fundamental concept in analytical chemistry and related fields. It refers to a graph that plots the known concentrations of a substance against the corresponding measured signals, such as absorbance, fluorescence, or current. This curve serves as a reference to determine the concentration of an unknown sample by comparing its measured signal to the values on the standard curve.

The process of creating a vakiokäyrä typically involves preparing a series of solutions with precisely known concentrations of the analyte. These solutions are then analyzed using the same method and instrument that will be used for the unknown samples. The measured signals are plotted against their respective concentrations, usually with concentration on the x-axis and the signal on the y-axis. A best-fit line or curve is then determined, often through linear regression, to represent the relationship between concentration and signal.

Once the vakiokäyrä is established, an unknown sample is analyzed, and its signal is measured. By locating this signal value on the y-axis of the standard curve and then tracing across to the fitted line and down to the x-axis, the corresponding concentration of the analyte in the unknown sample can be determined. The accuracy of the vakiokäyrä is crucial for obtaining reliable results, and factors like the quality of standards, instrument calibration, and the linearity of the response are carefully controlled.