1) Turn on digestion block and heat to appropriate temperature (420 oC).
2) Accurately weigh 0.5-1 g ground sample into digestion tube. Record the weight (W). Place in digestion tube.
3) Add 5 g catalyst powder and appropriate volume of conc. sulfuric acid (e.g. 15 ml) to each tube with sample. Prepare duplicate Blanks: 5 g catalyst powder + 15 ml conc. sulfuric acid.
4) Place rack of digestion block tubes on digestion blocks. Cover digestion block with exhaust system turn on.
5) Let sample digest for 45 min and cool for 15 min. The samples should be clear with no charred material remaining. Let sample cool
6) Take samples off the digestion block and allow to cool with exhaust system still turned on.
7) Carefully diluted digest with 50 ml dd water, Swirl each tube.