standardikäyrät

Standardikäyrät, often translated as standard curves or calibration curves, are graphical representations used in analytical chemistry and other scientific fields to determine the concentration of an unknown analyte. They are constructed by plotting the measured response of an analytical instrument (such as absorbance, fluorescence intensity, or peak area) against a series of known concentrations of a standard solution. The standards are carefully prepared solutions containing the analyte of interest at precisely known amounts.

The process involves preparing at least three, and preferably more, standard solutions covering a range of concentrations that are expected to bracket the concentration of the unknown sample. After measuring the instrument response for each standard, these data points are plotted on a graph with concentration on the x-axis and instrument response on the y-axis. A line or curve is then fitted to these points, typically using linear regression if the relationship is linear.

Once the standard curve is established, the instrument response for an unknown sample is measured under the same conditions. By locating this response value on the y-axis of the standard curve and drawing a horizontal line to intersect the curve, the corresponding concentration can be read off the x-axis. This allows for the quantitative determination of the analyte in the unknown sample. The accuracy of the standard curve is crucial for obtaining reliable results, and it is often validated by analyzing quality control samples.