BS ISO 23305;2020 pdf download.Fortified milk powders, infant formula and adult nutritionals Determination of total biotin by liquid chromatography coupled with immunoaffinity column clean-up extraction.
1 Scope
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.
3.1
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
3.2
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]
4 Principle
The sample is dispersed in sodium phosphate buffer and autoclaved at 121 °C ± 2 °C for 25 mm. The sample is cooled to room temperature and then diluted to 100 ml in a volumetric flask. The extract is centrifuged and filtered using a glass microfibre filter. Clear filtrate is collected for clean-up and
5.2.2 Sodium phosphate buffer, c = 0,15 mol/l. Weigh 9,15 g of sodium dihydrogen phosphate dihydrate and 16,31 g of disodium hydrogen phosphate dihydrate into a 1 1 volumetric flask, dissolve and make up to the mark with water. Adjust the pH to 7 with 2 mol/l sodium hydroxide.
5.2.3 Phosphoric acid, w = 0,1 %.
Into a 11 volumetric flask, transfer 500 ml water. Add 1,2 ml of ortho-phosphoric acid. Mix and make up to the mark with water.
5.3.1 Stock standard biotin, mass concentration p = 100 ig/ml.
Weigh 25 mg biotin standard in a 250 ml amber volumetric flask. Add 150 ml water and sonicate at room temperature for 90 mm with occasional shaking. Make up to volume with water.
5.3.2 Stock standard biocytin, p = 100 ig/ml.
Weigh 10 mg biocytin standard in a 100 ml amber volumetric flask. Add 60 ml water and sonicate at room temperature for 90 mm with occasional shaking. Make up to volume with water.
5.3.3 Mixed intermediate standard, p = 100 pg/100 ml.
Dilute 1 ml each of stock standards to 100 ml with water.BS ISO 23305-2020