Determination Of Myo-inositol Research Articles

Gold nanoparticles enhanced molecularly imprinted poly(3-aminophenylboronic acid) sensor for myo-inositol detection

Myo-inositol (MI) is a secondary messenger that can be used to treat a variety of metabolic syndromes (MS), from diabetes to cancer, and ongoing research is reassuring a bright future for therapies. In this study, two molecular imprinting polymer (MIP) sensor matrixes were created and investigated for the determination of MI; (i) 3-aminophenylboronic acid (3-APBA) electropolymerization with MI as the template on the SPCE surface (ii) gold nanoparticles (AuNPs) initially electrodeposited on a screen-printed carbon electrode (SPCE) surface and further the molecularly imprinted poly-3-aminophenylboronic acid (PAPBA) sensor film was electropolymerized with MI on the modified AuNPs/SPCE surface. Here, the surface modification with AuNPs on SPCE better enhances the electrochemical signal compared with unmodified SPCE. The electrochemical characterization of molecularly imprinted sensors was evaluated via Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Differential Pulse Voltammetry (DPV) techniques. The morphological changes of the modified electrodes were analyzed by Scanning Electron Microscope (SEM). The performances of the imprinted sensors (such as extraction of the template, rebinding conditions, and interference study) were investigated and optimized. The overall analytical data of the MI/PAPBA/AuNPs/SPCE based imprinted sensor (linear range: 500 nM to 60 μM; limit of detection: 1.0 nM; sensitivity: 0.042 μA μM−1) was better than the MI/PAPBA/SPCE (linear range: 500 nM to 50 μM; limit of detection: 4.7 nM; sensitivity: 0.019 μA μM−1). Further, the MI/PAPBA/AuNPs/SPCE imprinted sensor was successfully validated by applying for the sensitive and selective detection of myo-inositol in human plasma samples, and the results agreed well with the HPLC literature data.

Determination of Myo-Inositol in Infant, Pediatric, and Adult Formulas by Liquid Chromatography-Pulsed Amperometric Detection with Column Switching: Collaborative Study, Final Action 2011.18.

AOAC First Action Method 2011.18, Myo-Inositol (Free and Bound as Phosphatidylinositol) in Infant and Pediatric Formulas and Adult Nutritionals, was collaboratively studied. With this method free myo-inositol and phosphatidylinositol bound myo-inositol are extracted using two different sample preparation procedures, separated by ion chromatography using a combination of Dionex Carbo Pac PA1 and MA1 columns with column switching, and detected with pulsed amperometry using a gold electrode. Free myo-inositol is extracted from samples with dilute hydrochloric acid and water. Phosphatidylinositol is extracted from samples with chloroform and separated from other fats with silica SPE cartridges. Myo-inositol is then released from the glycerol backbone with concentrated acetic and hydrochloric acids at 120°C. During this collaborative study, nine laboratories from five different countries analyzed blind duplicates of nine infant and pediatric nutritional formulas for both free and phosphatidylinositol bound myo-inositol, and one additional laboratory only completed the free myo-inositol analyses. The method demonstrated acceptable repeatability and reproducibility and met the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) Standard Method Performance Requirements (SMPRs®) for free myo-inositol plus phosphatidylinositol bound myo-inositol for all the matrixes analyzed. SMPRs for repeatability were ≤5% RSD at myo-inositol concentrations of 2-68 mg/100 g ready-to-feed (RTF) liquid. SMPRs for reproducibility were ≤8% RSD in products with myo-inositol concentrations ranging from 2 to 68 mg/100 g RTF liquid. During this collaborative study, repeatability RSDs ranged from 0.51 to 3.22%, and RSDs ranged from 2.66 to 7.55% for free myo-inositol plus phosphatidylinositol bound myo-inositol.

A flexible ion chromatography column-switching system with a switching time window (STW) calibration program for the determination of myo-inositol in infant formula by pulsed amperometric detection

The column-switching system allows for convenient determination and calibration of STW parameters.

Determination of Myo-Inositol in Infant, Pediatric, and Adult Formulas by Ion Chromatography-Pulsed Amperometric Detection and Column Switching: Collaborative Study, Final Action 2011.18

Determination of Myo-Inositol in Infant, Pediatric, and Adult Formulas by Ion Chromatography-Pulsed Amperometric Detection and Column Switching: Collaborative Study, Final Action 2011.18

Determination of myo-inositol in infant formulae and milk powders using capillary gas chromatography with flame ionisation detection

A gas chromatography–flame ionisation detection method was developed to establish the content of myo-inositol in milk powders and infant formulations subsequent to formation of the volatile trialkylsilyl derivative. Samples were prepared by acid digestion, thereby releasing inositol from its multiple bound forms. A digestion time of 4 h at 114 °C was sufficient to hydrolyse potentially interfering carbohydrates and quantitatively recover bound inositol from milk-based products. Single laboratory method validation showed a within-day relative standard deviation (RSDr) of 5.9% and between-day relative standard deviation (RSDiR) of 9.6%. A between-laboratory (n = 7) collaborative study yielded an average reproducibility (RSDR) of 12.8%, considered fit-for-purpose as a quality control method for milk-based infant formulations. Soy-based products, containing significant inositol hexaphosphate (IP6, phytic acid), required 32 h for release of all inositol. Although current regulations do not specify the inclusion of IP6 in an inositol measurement, the current method allows for its discrimination if present.

Fast separation and determination of free myo-inositol by hydrophilic liquid chromatography

A fast liquid chromatography method for separation and determination of myo-inositol is reported. Determination of the biologically important isomer of inositols, myo-inositol, was optimized to avoid overlapping to possible interferents according to European Pharmacopoeia (glycerol, d-mannitol) and saccharose. The method in HILIC mode is extremely selective to other carbohydrates which allows to separate myo-inositol from allo- and d-chiro-inositol with resolution 12.3 and 5.2, resp. and this way it enables to separate myo-inostiol from contingent carbohydrates present in a sample matrix. Retention time of myo-inositol was 12min at 10°C, though higher temperatures (25°C or 40°C) or higher water content in the mobile phase could speed up the separation and determination to four minutes. LOD of the method was 9mg/L at 10°C, and 5mg/L at 25°C, resp.

Determination of Phytate in Urine by High-Performance Liquid Chromatography?Mass Spectrometry

An indirect method is described for determination of phytate in human urine. The method is based on hydrolysis of the phytate and determination of myo-inositol, one of the hydrolysis products. Chromatographic separations were performed on an Aminex HPX-87C column with Milli-Q water as mobile phase; 5 mM ammonium acetate was added post-column. The detector counted positive ions by monitoring m/z=198, which corresponds to the adduct of myo-inositol with the ammonium cation. The relative standard deviations obtained for standards containing 0.5, 1, and 1.5 mg L−1 phytate were 4.1, 3.0, and 2.7% respectively (n=5). The limit of detection was 60 μg L−1. Different urine samples were analyzed both by this method and by an alternative analytical method based on GC–MS. The results from both methods were comparable.

Determination of myo-inositol in biological samples by liquid chromatography–mass spectrometry

Due to the absence of HPLC methods to determine myo-inositol using mass detection and considering its sensitivity and selectivity, a high performance liquid chromatography-mass spectrometry method for the analysis of myo-inositol is described and applied to its direct determination in urine and saliva samples. Successful resolution of myo-inositol and its related substances was achieved with a stationary phase Aminex HPX-87C Column with milli-Q water as mobile phase and 5 mM ammonium acetate added post-column. The detector counted positive ions by monitoring m/ z=198, which corresponds to the myo-inositol adduct with ammonium cation. Urine and saliva samples were previously purified by passing through an anion-exchange resin. Concentrations as low as 138 and 461 μg/l in saliva and urine could be respectively quantified. Intra-day R.S.D. ranged from 0.83 to 1.02%, whereas inter-day R.S.D. was between 1.54 and 3.58%.

Assay ofmyo-inositol in cerebrospinal fluid and plasma by chemical ionization mass spectrometry of the hexaacetate derivative

The paper describes a capillary gas chromatographic/mass spectrometric technique to quantitate myo-inositol in cerebrospinal fluid (CSF) and plasma. A highly abundant fragment ion, m/z 373, for the hexaacetate derivative of myo-inositol was generated by chemical ionization (CI). This ion and the analogous ion of hexadeuterated myo-inositol (the internal standard), m/z 379, were both monitored in the assay. CI was performed with acetonitrile vapor in an ion trap mass spectrometer. Microliter quantities of CSF or plasma were mixed with the internal standard, dried and acetylated. After a post-derivatization clean-up, samples were analyzed on a capillary gas chromatograph interfaced with a Finnigan ion trap. Standard curves constructed for both CSF and plasma were linear and reproducible. Absence of matrix effects and good precision in the results indicate the suitability of the technique for critical assays. Results from the determination of myo-inositol in the CSF and plasma of healthy subjects and those with neurological deficits are reported.

ENZYMIC DETERMINATION OF FREE MYOINOSITOL IN HUMAN CEREBROSPINAL FLUID AND PLASMA.

Abstract An enzymic micromethod for the determination of myoinositol in biologic fluids is described. Its sensitivity is greater than that of other enzymic methods previously reported, and its specificity appears to be high. The method is based on the fluorometric determination of the DPNH formed in the oxidation of myoinositol to myoinosose in the presence of inositol dehydrogenase. Deproteinization and treatment of the samples with hydroxylamine are performed before the enzymic assay. The free myoinositol content of samples from normal individuals has been determined by this procedure and found to be 1.09 mg. per 100 ml. (S. D. = 0.21) for plasma, and 2.55 mg. per 100 ml. (S. D. = 0.59) for cerebrospinal fluid. These values are compared with those previously obtained by other authors using microbiologic techniques.