ISO 17072-1:2019 pdf free.Leather——Chemical determination of metal content——Extractable metals.
WARNING — The concentrated acids used in this method are very corrosive and/or oxidising liquids, which could raise the possibility of fire in the event of contact with ignitable materials and promote an existing fire considerably, or could decompose explosively with warming. They might cause acute or chronic health dangers as well. Moreover, they are hazardous to water. Suitable safety measures are therefore necessary.
7 Sampling and sample preparation
7.1 If the leather piece available for testing is a whole hide or skin, then the test specimens shall be sampled in accordance with the standard procedures given in Iso 2418. If sampling in accordance with Iso 2418 is not possible (e.g. leathers are from finished products like shoes or garments), details about the sampling shall be given in the test report.
7.2 Prepare the leather sample in accordance with Iso 4044. Test pieces that are wet (in excess of
30 % moisture) should be pre-dried for at least 12 h, at a temperature not exceeding (50 ± 2) °C. The drying temperature should be selected while considering the influence of elevated temperature on the nature of the analyte.
7.3 Determine the volatile matter content in accordance with Iso 4684. The same sample of leather can be used for the extraction in 8.2.
8 Procedure
8.1 Preparation of acid artificial-perspiration solution
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 monohydrochioride monohydrate (5.3);
— 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 (5.3) and place in a 250 ml Erlenmeyer flask (5.8).
Add 100 ml of the acid artificial-perspiration solution (&1) by pipette and, at (37 ± 2) °C, shake (&10) in a water bath (6.10) 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 the filtration doesn’t cause a partial loss of these elements. For the direct measurement of the elements, take a suitable amount of extract for analysis and add 5 % (by volume) of nitric acid (5.2). Consider this addition in the dilution factor. To control the contaminants, it will be necessary to carry out a blank procedure. An aliquot of acid perspiration is placed in a sample container and treated as a sample, in all respects, including all analytical procedures. The above extraction conditions shall be followed exactly. Any deviation would lead to the wrong results. In the case of mercury (Hg) determination, add 10 uI of gold solution (5.10) at the same time as the acid artificial-perspiration solution.
8.3 Analysis by ICP, AAS and SFA
8.3.1 General
The solution obtained in 8.2 can be analysed directly, provided it contains a concentration of analysed metals within calibration limits. Otherwise, the solution should be diluted as appropriate.
Prepare standard reference solutions of the required metals in accordance with ISO 11885, using perspiration solution (&1) water or acidified water.ISO 17072-1 pdf download.