BS ISO 20637:2015 pdf free.Infant formula and adult nutritionals—Determination of myo-inositol by liquid chromatography and pulsed amperometry.
BS ISO 20637 specifies a method for the determination of myo-inositol (free or free plus bound as phosphatidylinositol) in infant formula and adult nutritionals using liquid chromatography and pulsed amperometry with column switching.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1 adult nutritional nutritionally complete, specially formulated food, consumed in liquid form, which may constitute the sole source of nourishment, made from any combination of milk, soy, rice, whey, hydrolysed protein, starch and amino acids, with and without intact protein
2.2 infant formula breast-milk substitute specially manufactured to satisfy, by itself, the nutritional requirements of infants during the first months of life up to the introduction of appropriate complementary feeding [SOURCE: Codex Standard 72-1981]
3 Principle
Free myo-inositol and phosphatidyl bound myo-inositol are extracted using two different sample preparation procedures. 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 solid phase extraction cartridges. Myo-inositol is then released from the glycerol backbone with concentrated acetic and hydrochloric acid at 120°C. The ion chromatographic method uses a combination of two different ion exchange columns with column switching and pulsed amperometric detection (PAD). The concentration of myo-inositol is calculated by comparison with external standards of known concentration.
4 Reagents and materials
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and distilled or demineralized water or water of equivalent purity.
4.1 Chemicals and solvents
4.1.1 Acetic acid, glacial, ACS.
4.1.2 Chloroform, high-purity, HPLC grade.
4.1.3 Diethyl ether, anhydrous, HPLC grade.
4.1.4 Drierite, (desiccant), anhydrous calcium sulfate, 8 mesh.
4.1.5 Helium, zero grade or equivalent.
4.1.6 Hexane, HPLC grade.
4.1.7 Hydrochloric acid, concentrated (36 % to 38 %), ACS.
4.1.8 Metaphosphoric acid, ACS.
4.1.9 Methanol, HPLC grade.
4.1.10 Myo-inositol, primary reference standard, official lot, store desiccated. See standard label for purity.
4.1.11 Sodium chloride, ACS.
4.1.12 Sodium hydroxide, 50 % (m/m), low carbonate form.
4.2 Preparation of reagents and standard solutions
4.2.1 General. AIl solutions can be scaled up or down for convenience provided good laboratory practices are observed. Solutions can be stored at refrigerated or at ambient temperature in tight, inert containers unless otherwise specified.
4.2.2 Myo-inositol stock standard solution (approximately 2 000 mg/). Accurately weigh approximately 0,100 g myo-inositol and quantitatively transfer to a 50 ml volumetric flask. Dilute to volume with water. Mix well. Store refrigerated. Expiration: 3 months.BS ISO 20637 pdf download.