For the accurate determination of serum cholesterol, a reference method using gas chromatography/flame ionization detector(GC/FID) using epicorostanol as an internal standard and a definitive method with isotope dilution-mass spectrometry (ID-MS)
with
[25, 26, 17-13 C] cholestrol as internal standard and a benchtop gas chromatography/mass spectrometer (GC/MS) are described. After saponification, extraction and derivatization of cholesterol, cholestrol trimethylsilyl eher is separated by high
resolution capillary column and detected by FID or MS. Quantitation is achieved by measuring the peak area ratio between cholesterol and internal standard. The cholesterol in reference serum (NIST SRM 909), commercially available serum, or
KRISS-made
lyophilized serum (KRISS NOR and KRISS ABN) was determined by these two methods. When comparing the measured values with the assigned value in NIST SRM 909, the reproducibility (CV<1%) and the accuracy of the methods are acceptable.
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