Principles Of Process Analyzer Calibration

Component isolation is the only way to ensure interference-free measurement. Environmental Protection Agency protocols are good examples of procedures for calibration and documentation. The short- and long-term stability of the measurement system will dictate the method of calibration. Comparisons can be made by introducing a known amount of reference component into the unknown sample. The concentration of the target analyte is calculated from the ratio of the responses of the reference and target components. The term “calibration sample” implies absolute knowledge of component concentration based on the best practices, materials, and equipment used to prepare it from first principles such as weight, volume, pressure, or flow. Statistical treatment of multiple measurements will produce an average value with confidence limits. Changes in component concentration with time may appear as analyzer drift, indicating instrument instability. Shelf life of standards must be established and indicated on the container label.