Which factor affects the accuracy due to the calibration procedure?

• A. The duration of the measurement
• B. The calibration procedure
• C. The lab's HVAC settings
• D. The operator's preferred color of pen

Answer: (B)

The main idea is that accuracy in XRF results depends on how the instrument is calibrated. The calibration procedure establishes the relationship between the detected signal and the actual element concentrations. It involves selecting appropriate standards, setting the energy calibration, accounting for matrix effects, correcting background and peak overlaps, and applying corrections for detector drift and dead time. If any of these steps are flawed or ill-suited for the sample, the calibration curve will misrepresent true concentrations, causing biased (inaccurate) results across measurements.

The duration of the measurement mainly influences precision (statistical uncertainty) through counting statistics, not the calibration bias. HVAC settings can affect instrument stability and drift, but they don’t define the calibration itself unless drift is uncorrected. The color of the pen is irrelevant to calibration.