Preliminary study to develop two levels of lipoprotein(a) serum reference materials using isotope dilution mass...

Two levels of lipoprotein(a) serum reference materials were developed and a candidate reference method was established. After the selection of the peptide for calibration, peptide synthesis, peptide purity analysis, optimization of pretreatment methods, and chromatographic and mass spectrometric methods, an isotope dilution mass spectrometry method based on peptide digestion was established for the calibration of the lipoprotein(a) serum reference materials. The final results were 212.50 and 40.82 nmol L^-1 for the two levels of serum reference materials, respectively, which were statistically analyzed, including outlier and normal distribution tests, and the final results were good. Moreover, the homogeneity test, stability test, and uncertainty evaluation were conducted for the serum reference materials, and the final standardization results could be expressed as (212.50 ± 21.99) and (40.82 ± 4.08) nmol L^-1, respectively. The stability test results showed that the two levels of serum reference materials for lipoprotein(a) could be stably preserved at -20 °C for six months. The reference materials are expected to be used as primary calibrators for quality control in clinical diagnostics.