BS EN 17265:2019 pdf free.Foodstuffs – Determination of elements and their chemical species – Determination of aluminium by inductively coupled plasma optical emission spectometry (ICP-OES).
If precipitations or turbidities are visible in the digestion solutions, low findings can occur. In these cases, use smaller test portions and higher digestion temperatures up to 300 °C in order to minimize or avoid possible low findings.
NOTE Turbidities or small amounts of precipitates adhering to the wall or bottom of the vessel are oniy visible in vessels with high transparency (e.g. aluminium-free quartz vessels). Plastic vessels are often not completely transparent, making precipitates difficult to discern.Fill up the digestion solution obtained by pressure digestion to a defined volume, e.g. 20 ml. Add the internal standard (5.4.3) (e.g. 1 000 p1) to an aliquot of the digestion solution, e.g. 5 ml, and fill up with water to 10 ml. Separate insoluble residues before measurement. If the digestion solution has a different final volume than 20 ml and a different dilution factor than 2 after addition of the internal standard, adapt the acid concentration of the calibration solutions respectively. All test solutions shall have approximately the same acid concentration as the calibration solutions. The digestion solution shall be measured within 2 weeks.
Matrix effects can occur in digestion solutions. It is recommended to dilute the digestion solution by a factor of 2 to reduce matrix effects and avoid contamination of instruments.5.4.3 Scandium standard solution (internal standard solution), p = 10 mg/i. Fill approximately 10 ml of water into a 50-mi volumetric flask, add 2 ml of nitric acid (5.1) and mix. After cooling down to room temperature, pipette exactly 500 il of the scandium stock solution (5.3) to the flask and fill up with water to the mark. This standard solution is stable for at least 3 months. 5.5 Aluminium calibration solutions. The concentrations of the calibration solutions described are examples and may be changed according to the sensitivity of the measuring instrument and the concentration range to be analysed. Carry out the calibration within the linear range of the detector system. At least 3 calibration solutions of different concentrations should be prepared. Make sure that the acid concentration of the calibration solutions corresponds to the test solution. In order to avoid contaminations originating from the flask material, do not use volumetric flasks made from borosilicate glass. The information on contaminations provided in B.1 is to be regarded. Mix all calibration and test solutions as well as the zero-point solution (5.6) with an equal proportion of internal standard solution (5.4.3).
BS EN 17265 pdf download.