Pyrrolidone modified magnetic COF materials for the quantitative determination of 25-hydroxyvitamin D in human serum via isotope dilution mass spectrometry

Abstract

Vitamin D is indispensable for regulating the balance of calcium and phosphate and preserving the health of the skeletal system. Rapid and accurate detection of vitamin D content in the blood is crucial. In this work, we synthesized a magnetic COF material modified with pyrrolidone and p-aminobenzoic acid (Fe₃O₄@COF@Au@PABA@APP) for quantifying 25-hydroxyvitamin D from serum via isotope dilution mass spectrometry. The developed method demonstrated excellent linearity (R² > 0.99) across the 1–200 ng mL⁻¹ calibration range, a low detection limit (0.50 ng mL⁻¹), a good recovery rate (97.69%–103.16%), and low intra-day (<6.04%) and inter-day (<7.50%) variations. The measurement uncertainties for 25-OH VD₂ and VD₃ were determined to be about 3.46% and 3.60%, respectively. The VD in the serum of 20 volunteers was successfully measured by this method, which proved that the method had remarkable reliability and repeatability.