quality control sample

A quality control sample is a sample of known composition, very similar in terms of matrix and analyte concentration to the samples to be analysed. It is analysed along with the samples. The results are often plotted on a chart to monitor any significant drift in the performance of the analytical method - such a chart is known as a control chart . A quality control sample, often known as a QC sample or check sample may be an in-house material prepared for this purpose or it may be from a previously analysed batch of samples.