BUCHI Hydrolysis Unit B-411 - Manual (Page 18)

6 Operation
18 B-411/E-416 Operation Manual, Version E
Add 50 ml HCl, 4 mol / l and shake the tube to mix the sample with
the celite and the HCl.
Fig. 6.3: Adding HCI and mixing
Add another 50 ml HCl, 4 mol / l by pouring it along the side walls
of the digestion vessel to remove probable residues from the tube
wall.
In case of liquid samples, the acid concentration should be adjusted
to the water content of the sample.
Fig. 6.4: Adding HCl to rinse glass wall
6 .4 Preparing the glass sample tubes
Evenly distribute approx. 50 g quartz sand (grain size 0.3 - 0.9 mm).
The grain size is important, as in case it is too small, it will clog the
glass sample tube and in case it is too large, the celite will pass the
glass sample tube during the filtration step.
Fig. 6.5: Adding quartz sand
Add a layer of 5 g celite 545 in the glass sample tube.
Fig. 6.6: Adding celite