ISO 771:2021 pdf download – Oilseed meals — Determination of moisture and volatile matter content.
6 Sample 6.1 Sampling Sampling is not part of the method specified in this document. A recommended sampling method is given in ISO 5500. A representative sample should have been sent to the laboratory. It should not have been damaged or changed during transport or storage. 6.2 Preparation of test sample Prepare the test sample in accordance with ISO 5502. Grind the contract sample in the previously well- cleaned mechanical mill (5.2), collect the grindings, mix carefully and carry out the analysis without delay. 7 Procedure 7.1 Carry out two determinations on each sample. 7.2 Weigh the vessel to the nearest 0,001 g with the lid (5.4), after leaving it open for at least 30 min in the desiccator (5.6) at laboratory temperature. Note mass m 0 . 7.3 Weigh, to the nearest 0,001 g, about 5 g of the test sample into the vessel (5.4), spread the sample uniformly over the whole base of the vessel, and re-weigh with its lid. Carry out these operations as quickly as possible, in order to avoid any appreciable change in moisture content. Note mass m 1 . 7.4 Place the vessel with the test portion in the oven (5.5), which has previously been set to a temperature of (103 ± 2) °C, and take off the lid. If several vessels are in the oven together, arrange them in such a way that air can circulate freely between them. 7.5 Close the oven. After 2 h, reckoned from the time when the temperature in the oven has returned to (103 ± 2) °C, open the oven, replace the lid on the vessel before removal from the oven and transfer to the desiccator. As soon as the vessel has cooled to laboratory temperature, weigh it to the nearest 0,001 g. During the drying, do not open the oven to add other test portions.
9 Precision 9.1 Results of interlaboratory test Details of an interlaboratory test on the precision of the method are summarized in Annex A. The values derived from this interlaboratory test might not be applicable to concentration ranges and matrices other than those given. 9.2 Repeatability The absolute difference between two independent single test results, obtained using 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 not more than 5 % of cases be greater than r given as followed: — for mean value less than 4,0 % (in mass fraction): r = 0,2 %; — for mean value more than 4,0 % (in mass fraction): r = 0,018x + 0,13 (see Figure A.1). With x corresponding to the mean value of two reps. Some examples of r values are given in Annex B. 9.3 Reproducibility The absolute difference between two single test results, obtained using the same method on identical test material in different laboratories with different operators using different equipment, will in not more than 5 % of cases be greater than R given as followed: — for mean value less than 4,0 % (in mass fraction): R = 0,4 %; — for mean value more than 4,0 % (in mass fraction): R = 0,033x + 0,27 (see Figure A.1). With x corresponding to the mean value of two reps. Some examples of R values are given in Annex B.