BS ISO 20637:2015 pdf free

BS ISO 20637:2015 pdf free.Infant formula and adult nutritionals一Determination of myo-inositol by liquid chromatography and pulsed amperometry
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.
Prepared samples that are constantly stored at 1 °C to 8°C in closed containers are stable for up to 5 days. After 5 days, samples shall be prepared again. Thoroughly mix or stir products prior to sampling.
Mix liquid samples well to ensure homogeneity. If the powder sample homogeneity is unknown, assume that it is non-homogenous and proceed with the preparation of dry blended/non-homogenous powder samples given in 6.2.1.3.
In a fume hood, condition a 1 g silica SPE cartridge (5.20) with 6 ml hexane. Dissolve residue in the bottom of the centrifuge tube in 1 ml chloroform:methanol (2:1). Quantitatively transfer dissolved residue to the conditioned silica SPE cartridge. Rinse the 50 ml centrifuge tube with 3 ml hexane:diethyl ether (80:20) and then transfer to the SPE cartridge. Discard the eluent. Rinse the 50 ml centrifuge tube with 3 ml hexane:diethyl ether (50:50) and then transfer to the SPE cartridge. Collect eluent in a clean 50 ml centrifuge tube. Rinse 50 ml centrifuge tube with 4 ml methanol and then transfer to the SPE cartridge. Collect eluent in the same 50 ml centrifuge tube. Rinse 50 ml centrifuge tube with 4 ml methanol:chloroform:water (75:15:10) and transfer to the SPE cartridge. Collect eluent in the same 50 ml centrifuge tube. Evaporate eluents collected from SPE cartridge with nitrogen in a 60 °C water bath.
In a fume hood, add 40 μl glacial acetic acid (4.1.1) and 2 ml concentrated hydrochloric acid (4.1.7) to the residue in the centrifuge tube from the sample cleanup step. Tightly cap tube. Heat in a 120 °C oven for 2 h. Cool. Add approximately 10 ml of water and swirl to mix. Add 1,25 ml 50 % (m/m) sodium hydroxide (4.1.12). Transfer sample to a 50 ml volumetric flask and dilute to volume with water. Filter an aliquot of sample filtrate through a 0,45 μum syringe filter into an autosampler vial.BS ISO 20637 pdf free download.