ASTM E1645:20 pdf download.Standard Practice for Preparation of Dried Paint Samples by Hotplate or Microwave Digestion for Subsequent Lead Analysis.
(2) Any visible traces of paint left in the original container or container used for homogeniation (diferent from original container) may rosult in bias of the final lead aralysis rcosults.
Therefore, such trncs shull tbe minimized Any visibe materal thus Cinnot be trnaosfered sbull be documemted in sumple preperation reconds.
(3) For sample traosfers fllowing homogenizatice. most losses caused by the prcsence of fie pow der remaining in the original container or container used for homogenization Gf different from original container) will not result in any signi6. cant bias (particularly with respect 10 the larpe sampling variability that normally accorpaunies the feld collection proctice.)
14)For sumople transfars prlor 1o homppenizaton (that uben homopenization cannoi be performod in the origisal container used in sample collection), amy losses caused by fine pogder remaining in the original container may result in significant bias. Therefore, sample transfers conducted prior to samplk homogenization shall be perfomned with extn attention to avoiding visible traces of paint left in the original coealiner.
7.1.24 Homogenartion of Samples- Samples shall be bormogenized as finely possiblke, regandess of sbether area concentration or mass concentration results are desired. The homogenizaticm of the sample serves two purposes) to ensure thal the subsaomples wil be reprosentative of thr whoke
collkeded sample; and b 10 maximixe the cutraction and digestion eficiency of the sample. Any sample bomogeintio ochnique that meets the follon ing criteria may be used
1 Samples shall be pround, crusbed boken inlo a hnr poader or small granules consisting of pa rticles no larger than that visully represcented by the sire of a poppy seed or small grain of sand (0o larger than 0.5 mm in diamcter)
(2) Samples shall not be contaminated from amy other previously processed sample. This means that the sumple homogenizatloe tecbsalgpe s armied out such thut careful cleaning between samples is perfonned the equipeent used
10 process multiple samples.
7.1.25 Hor Plate Digestiores- Determine the mass to the nearest 0.1 mg. of a 0.25 E 10 0.50 g subsample of the homogenized sample and place it into a ckean, labcked 125-mLor 50-mL beaker.