主题：【讨论】玩具新标准EN 71-3:2013正式出台，标准细节探讨

大家关注的正式版EN 71-3:2013已经出版发行了，与旧版相比，除了有机锡、六价铬外，里面有一些细节说明比较详细，如除蜡部分：If the toy material contains any grease, oil, wax or similar material, material shall be de-waxed. De-waxing shall not be carried out on test portions being analysed for organic tin. Dry a high retention filter paper (see 6.2.6) for 4 hours at 37°C. Weigh the filter paper to the nearest 0,1 mg (Wfp1). The filter paper used should be as small as possible without risking loss of the test portion during the de-waxing procedure. Weigh the test portion, to the nearest 0,1 mg, onto the pre-dried and weighed filter paper. Fold the filter paper carefully to enclose the test portion without loss. Extract the test portion within the filter paper with boiling n-heptane (6.2.5) using suitable laboratory apparatus. The use of a de-waxing step shall be reported (see clause 10 h)).

After removal of non-polar ingredients, dry the folded filter paper containing the dewaxed test portion in an oven at 37°C ± 2 for 4 hours to ensure the removal of residual solvent. Weigh the dried filter paper parcel, to the nearest 0,1 mg (Wfp2). Use Wfp2 for the  calculation under 7.4.2.1 on the volume of 0.07 M HCl.

7.4.2.1 Weigh, to the nearest 0,05g, Wfp2 x 25 g of water at approximately 20 C into the extraction container containing the filter paper parcel. Then add the same mass of 0,14 mol/L hydrochloric acid solution (6.1.2) at approximately 20°C and mix.

除蜡后加入水和酸的重量（体积）应该是除蜡后按滤纸的重量来计算得来的，样品重量与最终溶液体积有可能不是50倍了。但平时都习惯了统一按除蜡前的样品重量的25倍来计算水和酸的体积。

不知大家的做法是怎样的。