Horns (also known as probes) are made from titanium and machined to specific sizes and shapes. When driven at their resonant frequency, they expand and contract longitudinally. This mechanical vibration is amplified and transmitted down the length of the probe. In liquid, the probe causes cavitation which constitutes the main mechanism for sample processing.
Choosing the appropriate horn is extremely important. The sample volume which can be processed is directly related to the tip diameter. Smaller tip diameters deliver high intensity sonication, but the energy is focused within a small, concentrated area. Larger tip diameters can process larger volumes, but offer lower intensity. Probes are offered with replaceable or solid tips.
Probe tips will pit or erode over time and require replacement. Using an excessively worn tip can affect your results and possibly overload the generator.
|10 - 250 ml
|1/2" (12.7 mm)
|25 - 500 ml
|3/4" (19.1 mm)
|50 - 1000 ml
|1" (25.4 mm)
Why can't replaceable tip probes be used with organic solvents?
Replaceable tips screw into the probe with a normal threaded screw. Low surface tension organic solvents can seep between the replaceable tip and the probe and get onto the threading, lubricating it. If this happens, the vibration of the probe can begin to unscrew the tip. This can damage or destroy the threading and can also potentially damage the converter if the probe cannot vibrate properly.
Why are the sapphire tip probes no longer available?
They were discontinued. The sapphire tips were specially bonded to the end of the solid probes with a compound that was sensitive to non-aqueous solvents and too many users reported problems with the sapphire coming unbound.
If you have an abrasive material, use a replaceable tip probe instead. If you have a low surface tension solvent and cannot use a normal replaceable tip probe, you may consider using a replaceable tip probe in conjunction with an extender, which will screw into the end of the replaceable tip probe and are less expensive to replace but are long enough that the joint does not need to be exposed to the solvent.Qsonica 2014-06-16