BS ISO 20647:2015 pdf download – Infant formula and adult nutritionals — Determination of total iodine — Inductively coupled plasma mass spectrometry Alternatively, for a smaller volume, dilute 50 ml of 5 % KOH and 10 ml of stabilizer concentrate (3.10.3) to 500 ml with purified water. The resulting concentrations for both preparations are 0,5 % KOH, 0,2 % NH 4 OH, and 0,02 % Na 2 S 2 O 3 in purified water. Store this solution at room temperature. Reagent expires 6 months after preparation date. 3.10.6 Conditioning solution Prepare by aliquoting 25 ml of KOH solution (3.10.2), then dilute to 250 ml with purified water. Use this solution to prepare the instrument for analysis. The resulting concentration is 5 g/l KOH. Store this solution at room temperature. Reagent expires 6 months after preparation date. 3.10.7 Carrier solution This solution is equivalent to the wash solution (3.10.4). The carrier solution is used to deliver the sample solution to the nebulizer through the ICP-MS autosampler introduction system. The carrier solution is introduced via a peristaltic pump using 0,76 mm inside diameter (id) two-stop polyvinyl chloride pump tubing. Store this solution at room temperature. Reagent expires 6 months after preparation date. 3.11 Preparation of standard solutions 3.11.1 General Stock solutions are stable until the end date indicated on the certificate of analysis. Intermediate stock standard, calibration standard, continuing calibration verification and internal standard solutions are stable at room temperature until the earliest expiration date of all components used to prepare the solution. These solutions are ready to use for analysis. Do not subject them to any of the various procedures used to prepare actual samples (i.e. infant formulas and adult nutritionals) for analysis. 3.11.2 Stock iodine and praseodymium solutions Purchase of stock iodine and praseodymium standard solutions with accompanying certificates of analysis is recommended. 3.11.3 Intermediate stock standard (ISS) iodine solutions Prepare the intermediate stock standard iodine solutions according to Table 1. These ISS solutions are used for calibration standard preparation and are typically prepared according to Table 1. The ISS concentrations presented are nominal. Using the stock iodine concentration found on the certificate of analysis, determine the exact concentration of each ISS. An electronic adjustable volume pipet, capable of delivering 100 µl to 5 000 µl should be used. 3.11.4 Calibration standard (CS) iodine solutions Prepare the intermediate stock standard iodine solutions according to Table 2. Typical CS standard concentrations...
Download Address
Download