For many quantification assays, a set of standards must be run alongside test samples in order to calibrate an experiment properly. These standards are used to create what is known as a calibration curve, or standard curve. From this curve, the quantity of target in a sample can be calculated.

Standards for the calibration curve are typically chosen such that they span the linearity of a given assay. This represents the range of quantities over which response values are directly proportional to changes in the target of interest. For many quantification assays, the linearity range is logarithmic in nature. Thus, when creating standards for a given assay, it is often necessary to prepare the standards using a serial dilution.

A serial dilution is a sequence of dilutions created using the same dilution factor. For instance, creating a two-fold dilution with a starting concentration of 10 µM yields the following concentrations: 10 µM, 5 µM, 2.5 µM, 1.25 µM, etc.

The tool below can be used to create a protocol for preparing a serial dilution from a stock solution.