A blank solution is a solution that does not contain the analyte, or the substance of interest being tested or measured. It is typically prepared using the same reagents and procedure as the sample solution but without adding the analyte. The primary purpose of preparing a blank solution is to account for any background interference or contamination that may affect the accuracy and reliability of the analytical method.

In some experimental cases, the reagents, solvents, or lab equipment used in an analysis can produce a detectable signal. By measuring the blank solution, this background signal can be determined and subtracted from the measurements of the sample solutions to ensure that the observed signal is solely attributed to the analyte. The laboratory environment can also introduce contaminants such as dust, airborne particles, or residues from previous experiments. Thus, blank solutions help identify and correct contamination during the sample preparation or analysis.

Moreover, the blank solution is sometimes used to calibrate instruments or measurement systems. By establishing a baseline with the blank solution, the instrument's response can be standardized and provide accurate measurements that can be obtained for subsequent sample analysis.