ISO 17072-1-2019 pdf free.Leather – Chemical determination of metal content – Extractable metals. Preparation of acid artificial-perspiration solution, shall be in accordance with ISO 105-E04. The solution shall be freshly prepared each day, containing, per litre: — 0,5 g of L-histidine monohydrochloride monohydrate (53); — 5 g of sodium chloride (SA); — 2,2 g of sodium dihydrogen phosphate dihydrate (5.5). The solution is brought to pH (5.5 ± 0.1) with 0,1 mol/l sodium hydroxide solution. 8.2 Extraction of leather sample Weigh accurately 2 g of the prepared leather to the nearest 0,00 1 g using an analytical balance (&3) and place in a 250 ml Erlenmeyer flask (5). Add 100 ml of the acid artificial-perspiration solution (&1) by pipette and, at (37 ± 2) °C, shake (f J.Q) in a water bath (6J) for 4 h ± 5 mm. In case of insufficient sample, it is possible to sample 1 g of leather, but in this case the extraction shall be performed with 50 ml of the acid artificial-perspiration in a 150 ml Erlenmeyer flask. Filter the extract with a filter paper (6.6), then filter with a membrane filter (6.5). In the case of Sn, Sb, Pb determination, check that…