Standardkurvor

Standardkurvor, also known as calibration curves, are graphical representations that relate an analytical instrument’s response to known concentrations of an analyte. They are used to quantify the amount of a substance in unknown samples by comparing the measured signal to the curve obtained from standards. Calibration curves are common in spectrophotometry, chromatography, immunoassays, and many molecular assays, and they support decisions in chemistry, biology, environmental testing, and clinical diagnostics.

To construct a standardkurv, a series of standards with precisely known concentrations is prepared and measured under the same conditions as the samples. The instrument response (such as absorbance, peak area, or signal intensity) is plotted against concentration. A model, typically a linear regression, is fitted to the data, yielding an equation that converts a measured response into concentration. The curve is assessed for linearity, typically using the coefficient of determination (R2) and residuals. The dynamic range of the curve should cover the expected sample concentrations, and blanks are used to correct for background signals. In some cases, nonlinear models, weighting, or data transformations are employed to improve fit.

Applications require careful handling of matrix effects, controls, and quality assurance. External calibration, standard addition, or matrix-matched standards may be chosen depending on interference from the sample matrix. Regular recalibration and documentation ensure traceability and accuracy in quantitative analyses.