Modification of the IFCC reference measurement procedure for determination of HbA(1c) by HPLC-ESI-MS

The reference measurement procedure for determination of HbA(1c) (glycated haemoglobin) using HPLC(high performance liquid chromatography)-ESI(electrospray ionisation)-MS(mass spectrometry) has been modified. Main modifications were a change in the buffer composition of the HPLC, a change in the gradient elution profile and the introduction of a post-column splitting system. The long-term stability of the HPLC-ESI-MS system proved to be of high importance to get reproducible results. Using the modified HPLC conditions stable retention times, high peak symmetry and a good column batch-to-batch reproducibility of the analytical results were obtained. The mean deviation from the target values was less than 0.7% with an imprecision of less than 2%.