Ion chromatography as potential reference methodology for the determination of total calcium and magnesium in human serum.

The potential of ion chromatography to serve as a new reference method principle for the determination of total calcium and magnesium in human serum was investigated. Sample pretreatment consisted of acidic dilution and filtration. Detection was based on conductivity. Mean total coefficients of variation for calcium and magnesium were respectively 0.91% and 1.20% and the mean method bias was +0.06% for calcium and -0.35% for magnesium, as determined with five control materials from the Community Bureau of Reference and the National Institute of Standards and Technology. These results were comparable to those of the proposed candidate reference methods based on flame atomic absorption spectrometry. Therefore, we consider ion chromatography as a valuable reference methodology for the determination of total calcium and magnesium in human serum.