Instrument calibration is one of the primary processes used to maintain instrument accuracy. There are few needs for calibration, calibration is the process of configuring an instrument to provide a result for a sample within an acceptable range. Calibration also to determine, check, or rectify the graduation of (any instrument giving quantitative measurements). Additional to divide or mark with gradations, graduations, or other indexes of degree, quantity, etc., as on a thermometer, measuring cup, or the like.

Although the exact procedure may vary from product to product, the calibration process generally involves using the instrument to test samples of one or more known values called “calibrators.” Some may use direct injection from cylinder gaseous (alayzers) with knew calibration concentration. The results are used to establish a relationship between the measurement technique used by the instrument and the known values.