... its own design and processing of a digestion rack, the digestion rack 55cm long , wide 23cm, high-9 ... hole can hold a test tube (25 × 200mm), which each can hold 96 test tubes, so that digestion ... with the conventional method compared to standard material test results, high accuracy. Third is fast, because ... is a practical, simple design of the digestion rack, reasonable, and generally at the county level ...