BS EN 17246:2019 pdf free.Fertilizers – Determination of perchlorate in mineral fertilizers by ion chromatography and conductivity detection (IC-CD).
8.2 Preparation of the test solutions and sample analysis With the analytical balance (6.3), weigh (25 ± 0,1) g of ground sample. Transfer the test portion to a 250 ml volumetric flask and add 150 ml of water (5.1) to dissolve the sample. Add additional water (5.1) until the indicated volume is reached. Stir manually to homogenize (= solution 1). Take an aliquot of 5 ml of solution 1 and transfer quantitatively to a 50 ml volumetric flask. Add water (5.1) to the mark and stir manually to homogenize (= solution 2). Keep the remainder of solution 1. Take an aliquot of 10 ml of solution 2 and transfer quantitatively to a 50 ml volumetric flask. Add water (5.1) to the mark and stir manually to homogenize (= solution 3). Keep the remainder of solution 2. Filter 10 ml of solution 3 using a filtration membrane (6.5). Discard the first filtrate collected. Filter another 10 ml and collect in a 10 ml vial. Proceed according to the operation instructions for the given instrument. If the perchiorate concentration is below the lowest calibration point (0,05 mg/l), take solution 2 for the analysis. If the concentration exceeds the calibration range, dilute accordingly. NOTE If the concentration of the sample injected falls outside the calibration range, an extra dilution step can be taken.10.3 Repeatability The absolute difference between two independent test results obtained with the same method on identical test material, in the same laboratory, by the same operator, using the same equipment within a short interval of time, will in no more than 5 % of the cases exceed the values of r given in Table 2. 10.4 Reproducibility The absolute difference between two single test results obtained with the same method on identical test material, in different laboratories, by different operators, using different equipment, will in no more than 5 % of the cases exceed the values of R given in Table 2.BS EN 17246 pdf download.