Calibration Curve definition?

• A. A graph of known concentrations used to determine the concentrations of the unknown or to verify the proper functioning of an analytical instrument.
• B. A chart showing data trends over time.
• C. A table listing all calibration standards.
• D. A control chart used for QC.

Answer: (C)

A calibration curve is a graph that links instrument response to known concentrations so you can determine the concentration of an unknown sample from its response. To build it, you measure the instrument signal for several standards with known concentrations, plot the signal against concentration (often getting a straight line within the working range), and use that relationship to interpolate the concentration of any unknown sample. It also helps verify instrument performance and linearity within the calibrated range. The other descriptions describe different things: a chart of data over time is a trend analysis, a table of calibration standards is just the input list, and a control chart is for monitoring process QC—none of these define the concentration–response relationship that a calibration curve provides.