Determination of myo-inositol and D-chiro-inositol in dietary supplements by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD)

Myo-inositol and D-chiro-inositol are inositol isomers involved in key cellular functions. They are widely used in dietary supplements for their benefits in improving insulin sensitivity, hormonal balance, and fertility in polycystic ovary syndrome PCOS, as well as managing adiposity, hyperglycemia, and insulin resistance. Therefore, determining myo-inositol and D-chiro-inositol is essential to assess health supplement quality and efficacy. In this study, a simple and reliable analytical method to analyze myo-inositol and D-chiro-inositol in food supplements was developed and validated using high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The dietary supplements were ultrasonicated, centrifuged, and filtered before quantification. Myo-inositol and D-chiro-inositol were completely separated on a DionexTM CarboPacTM MA1 IC column (250 mm × 4 mm × 7.5 μm) with a gradient elusion using a 50 mM and 1M NaOH mixture at a flow rate of 0.4 mL/min. The method has good specificity, linearity (R2 > 0.999), and accuracy with repeatability and recovery satisfying the AOAC requirements. The limit of detection (LOD) and the limit of quantification (LOQ) of the two analytes were 0.5 mg/kg and 1.5 mg/kg, respectively. The method was applied to simultaneously determine myo-inositol and D-chiro-inositol in different dietary supplement products.