D. Procedures(a) Pre-treatment-Homogenize product if necessary, using noncontaminating equipment. Check for leaching metals if the ap- paratus consists of metal parts(b) Drying. In a crucible, weigh 10 20 g test portion to nearest 0.01 g. Dry in a drying oven, on a water-bath, or a hot plate at 100oC, if there is a risk ofheavy boiling in the ashing step. Proceed according to type of furnace. Ashing. 1) Ashing in a programmable furnace. Place(c) dish in fumace at initial temperaturenothigher than 100oc.Increase temperature at a maximum rate of 50°Ch to 450°c.Let dish stand for at least 8 horovemight continue according to(e). (2) Ashing in a rmace with thermostat following drying and pre-ashing in uffzefu apparatus described in B(d) See Figure 999.11. Place cruci- ble with the test portion covered with the glass cover on the ceramic plate, and let purified air coming through a glass tubesweep over the product. Put IR lamp down at the cover. Pre-ash product sample by increasing temperature slowly with IR lamp by gradually increasing temperature on hotplate to maximum. Final temperature on ceramic plate should then be about 300°C. Time required for pre-ashing var- ies with product. Put crucible in muffle furnace at 200-250°C and slowly raise temperature to 450°C at a rate of no more than 50°Ch. Let stand for at least 8 h or overnight. Take crucible out of fumace and let cool. Wet ash with 1-3 mL water and evaporate on wa ter-bath or hot plate. Put crucible back in fumace at no more than