Probes/tips must be submerged properly. If the tip is not submerged enough the sample will foam or bubble. If the tip is too deep it will not circulate the sample effectively. Both conditions will end up with poor results. Foaming often occurs with samples volumes below 1ml. Foaming can also be caused when the amplitude setting is too high.
In the drawings above: Figure A will create foam and will not process the sample. Figure B will not circulate the liquid effectively and therefore will not process the sample. Figure C indicates the correct set up and will achieve good results in the shortest processing time.
Many customers place tubes in ice (to control temperature) making it difficult to see the tip. We recommend filling a tube with water to match your desired sample volume.
Insert the microtip to the optimum depth. Draw a horizontal line on the microtip with a permanent marker to indicate where to stop inserting the tip. By using the mark on the probe you can ensure the correct tip depth each time when the tube is submerged in ice.