Determination of Myo-Inositol (Free and Bound as Phosphatidylinositol) in Infant Formula and Adult Nutritionals by Liquid Chromatography/Pulsed Amperometry with Column Switching: First Action 2011.18

Abstract

Myo-inositol is a 6-carbon cyclic polyalcohol also known as meso-inositol, meat sugar, inosite, and i-inositol. It occurs in nature in both free (myo-inositol) and bound (inositol phosphates and phosphatidylinositol) forms. For the determination of free myo-inositol, samples are mixed with dilute hydrochloric acid to extract myo-inositol and precipitate proteins, diluted with water, and filtered. For the determination of myo-inositol bound as phosphatidylinositol, samples are extracted with chloroform, isolated from other fats with silica SPE cartridges, and hydrolyzed with concentrated acid to free myo-inositol. Prepared samples are first injected onto a Dionex CarboPac PA1 column, which separates myo-inositol from other late-eluting carbohydrates. After column switching, myo-inositol is further separated on a CarboPac MA1 column using a 0.12% sodium hydroxide mobile phase; strongly retained carbohydrates are eluted from the PA1 column with a 3% sodium hydroxide mobile phase. Eluant from the CarboPac MA1 analytical column passes through an electrochemical detector cell where myo-inositol is detected by pulsed amperometry using a gold electrode. The method showed appropriate performance characteristics versus selected established standard method performance requirement parameters for the determination of myo-inositol: linear response; repeatability (RSDr) of 2%; and intermediate precision (RSDir) of 2.5%. Instrument LOD and LOQ were 0.0004 and 0.0013 mg/100 mL, respectively, and correspond to a free myo-inositol quantitation limit of 0.026 mg/100 g and a phosphatidylinositol quantitation limit of 0.016 mg/100 g. Correlation with the reference microbiological assay was good. The proposed method has been accepted by the Expert Review Panel as an AOAC First Action Method, suitable for the routine determination of myo-inositol in infant formula and adult nutritionals.

Quantification of plasma myo-inositol using gas chromatography–mass spectrometry

“…It is synthesized in only a few organs such as the testes, kidney and brain [1,2]. MI is a primary component of living cells, serving as precursor for inositol phosphates, phosphatidylinositol (PI) and phosphatidylinositol phosphate (PIP) lipids [3].…”

Urinary myo-inositol levels in Japanese schoolchildren with normal glucose tolerance

“…Myo-inositol (MI) is a six-carbon, cyclic polyalcohol that exists in many foods and organisms (1). The MI levels are highest in fruits, beans, grains, and nuts (2), and it has been estimated that a mixed North American diet provides human adults with approximately 1 g/day of MI (3).…”

Synthesis of inositol‐based star polymers through low ppm ATRP methods

“…Other studies have reported only one example of meso ‐inositol‐based star macromolecule preparation by ATRP, notwithstanding this reaction gave a core with five rather than the expected six 2‐bromoisobutyric ATRP initiating sites, leaving one of the hydroxyl functional group underivatised. meso ‐Inositol is a 6‐carbon cyclic polyalcohol, an isomer of glucose also known as myo ‐inositol, meat sugar, inosite, and i ‐inositol . It exists as nine stereoisomers, seven of which are optically inactive or meso.…”

“…It exists as nine stereoisomers, seven of which are optically inactive or meso. It occurs in nature in both free ( myo ‐inositol) and bound (inositol phosphates and phosphatidylinositol) forms . Free of phosphate form is a member of the vitamin B complex, formerly vitamin B 8.…”

“…meso-Inositol is a 6-carbon cyclic polyalcohol, an isomer of glucose also known as myo-inositol, meat sugar, inosite, and i-inositol. [28,29] It exists as nine stereoisomers, seven of which are optically inactive or meso. [28] It occurs in nature in both free (myo-inositol) and bound (inositol phosphates and phosphatidylinositol) forms.…”