Ultrasonic cavitation is often employed for sample preparation in pharmaceutical labs. High ultrasonic power density is ideal for these applications because it accomplishes the job quickly. This minimizes cavitation induced heat buildup that can cause chemical degradation of samples.
Sample prep is generally accomplished by suspending sample flasks in ultrasonic cleaners containing water and a surfactant. Cavitation generated by ultrasonic transducers passes through the flask walls to act on the sample.
Most equipment used in this application handles several flasks at once for production-scale operations. An alternative design has proved especially efficient by speeding up the sample prep process in pharmaceutical research laboratories. The secret is in the design.
Elma’s S50R Lab Sonicator for Sample Prep
The 0.75 gallon to 1.5 gallon capacity 37 kHz multifunction Elma S50R laboratory sonicator available from Tovatech has an inside diameter of 9.5 inches and a depth of 5.12 inches. It has several features that make it ideal for sample prep and similar applications based on ultrasonic cavitation.
A tank without a drain. Elma researchers determined that drains interfere with the distribution of cavitation energy and promote “dead zones” around the drain port. Eliminating the drain results in a more even distribution of cavitation.
A round tank configuration. This enhances mixing action by focusing cavitation in the center at the base of the flask. Says Tovatech Director Dr. Rachel Kohn, “The agitation is so intense that the fluid visibly rises in a conical shape inside the flask. So much power! When I saw this model in operation I was blown away.”
Similarly, a round tank enhances the distribution of cavitation action compared to square or rectangular configurations and thereby improves the unit’s sieve cleaning capability.
A powerful pulse mode to activate the unit’s 600-watt peak ultrasonic power vs. its 150 watt effective ultrasonic power. This is the unit’s key feature for fast, safe, sample prep and improved sieve cleaning capability.
A rear-mounted support rack to hold flasks at the proper depth in the water bath. Alternatively glass beakers can be fitted into the orifice of a special cover.
Other Lab Functions
The timer-equipped S50R lab technology cleaner is programmed to handle four common procedures employing ultrasonic cavitation. All are activated from an intuitive control panel, with the activated function indicated by an LED.
1. Sample prep as described above is activated by the sample prep key.
2. Degassing cleaning solutions or HPLC solvents is activated by the degas key. This initiates an on-off mode that causes air bubbles to form, rise and burst.
3. Sieve cleaning is activated by the sieve cleaning key to engage the powerful pulse mode. Cleaning is accomplished in a special sieve rack.
4. General instrument cleaning in a mesh basket is accomplished simply by turning the unit on.
Sieve and instrument cleaning use biodegradable ultrasonic cleaning solutions. These, as with water and a surfactant, must be degassed to clean most effectively.
Contact the scientists at Tovatech for more information on the S50R lab sonicator and cleaner or for answers to any ultrasonic cleaning questions you have.