A rapid and validated GC-MS/MS method for simultaneous quantification of serum Myo- and D-chiro-inositol isomers.

Background: Myo-inositol (MI) and D-chiro-inositol (DCI) are two paramount isomers of inositol, both vital in glucose and steroid metabolism. Deficits in MI, DCI or MI/DCI ratio are expressly concerned with several pathological process, whereas MI and DCI lack practical measurement for human specimen.

Methods: To quantify MI and DCI in serum samples simultaneously, a gas chromatography tandem mass spectrometry (GC-MS/MS) method was established. The process flow was optimized in ion source, derivative agent volume and reaction time. The performance characteristics were verified by commercial standards and clinical serums.

Results: This method was confirmed to be sensitive (LOD ≤ 30 ng/mL of MI, ≤3 ng/mL of DCI) and reproducible (RSD < 6 % for repeated analyses). Quantitative determinations performed good linearity within the measurement range of 0.500-10.00 and 0.005-0.500 μg/mL for MI and DCI respectively (R > 0.999). The recoveries of MI and DCI were 97.11-99.35 % and 107.82-113.09 %, respectively. This method was successfully applied to 114 clinical specimens. No significant matrix effect was observed in serum samples under current conditions.