BS ISO 23305:2020 pdf free.Fortified milk powders, infant formula and adult nutritionals — Determination of total biotin by liquid chromatography coupled with immunoaffinity column clean-up extraction.
BS ISO 23305 specifies a method for the quantitative determination of biotin and/or biocytin in fortified milk powders, infant formula and adult nutritionals in solid (i.e. powders) or liquid (i.e. ready-to-feed liquids and liquid concentrates) forms using liquid chromatography coupled with immunoaffinity column clean-up extraction.
Precision data from an interlaboratory study is given in Annex B. A comparison between data obtained with the method in this document and EN 15607 is given in Annex C.
7 Procedure
7.1 Sample preparation
7.1.1 For mass and loading volumes for the different ranges of product, see Table 1. A slurry may be used wherever product homogeneity is suspected or unknown.
For the slurry, reconstitute 25 g of powder (ml) with warm water (—50 °C) to a total mass of 200 g (m2). Mix thoroughly on a horizontal shaker for 20 mm and then sonicate at 50 °C for 10 mm. Cool to room temperature. For liquid samples, mix well to ensure homogeneity of the sample portion and weigh the specified quantity.
7.1.2 Weigh the sample/slurry (m3) into a 100 ml amber glass screw-cap bottle. See Table 1.
7.1.3 Add 0,15 mol/l sodium phosphate buffer to an approximate volume of 50 ml.
7.1.4 Swirl gently to mix.
7.1.5 Autoclave the sample preparation at 121 °C for 25 mm.
7.1.6 Cool the sample to room temperature. Quantitatively transfer the extract into a 100 ml volumetric flask and make up to the mark with 0,15 mol/l sodium phosphate buffer, mix well.
7.1.6 Cool the sample to room temperature. Quantitatively transfer the extract into a 100 ml volumetric
flask and make up to the mark with 0,15 mol/l sodium phosphate buffer, mix well.
7.1.7 Transfer the extract into a centrifuge tube and centrifuge the sample at 4 000 rpm for 15 mm.
7.1.8 Filter the sample using the glass microfibre filter paper () and collect the filtrate.
7.1.9 Set up the SPE manifold (6.5). Attach the immunoaffinity column (IAC) connected to a 10 ml reservoir. Drain off buffer just above the gel.
7.1.10 Load the sample filtrate onto the column in accordance with Table 1 and initialize the flow with the help of a vacuum pump.
7.1.11 Turn off the vacuum and let the solution pass through the column by gravity at a rate of one drop per second.BS ISO 23305 pdf download.