The analytical blank should be incorporated into the calibration curve. One or two-level standards are usually required to calibrate the Ion Chromatograph. For trace analysis, typical standard concentrations are 2 to 5 times sample concentrations.
- For anions, if the sample contains 50 ppb each of Cl–, NO3– and SO42–, the standard calibration should not exceed 250 ppb each of these anions.
- For cations, if the sample contains 10 ppb each of K+, Mg2+, and Ca2+, the standard calibration should not exceed 50 ppb each of these cations.