Additional Information

Site Information

 Loading... Please wait...


Ultrasonic Equipment for Sample Preparation

Content uniformity and potency assay tests for active pharmaceutical ingredients contained in drug products are performed when the API is removed or isolated from its carrier, called the excipient.The objective is total extraction of the analyte so that an accurate quantitative analysis can be carried out. Depending on the sample, sample prep can involve dissolving, digesting, dispersing, emulsifying, homogenizing, mixing or solubilizing.

Ultrasonic extraction is a method often specified by U.S. Pharmacopeial Convention (USP) for sample preparation. This is because the process is fast, thorough, and with the proper ultrasonic equipment, avoids thermal degradation of the API. An ideal ultrasonic cleaner for sample preparation is the 3.75 gallon, 37 kHz Elmasonic S375EL from iUltrasonic.

This equipment differs from many ultrasonic cleaners because of its tank configuration: 20 inches by 12 inches but only 4 inches deep, and its 300 watts of effective ultrasonic power. This high power per unit volume means sample prep is completed before heat buildup due to sonic energy causes sample degradation. In addition, the separately ordered 17.9 x 9.8 x 2.2 in. deep basket suspends samples at the correct depth for maximum sonication efficiency.

Ultrasonic energy extracts the API from the excipient for content uniformity and potency assay tests.

Note that some labs prepare samples in deep ultrasonic baths by under filling the tank. This is not a good idea because tanks are tuned to operate optimally when they are at least two-thirds full. Decreasing the liquid volume reduces sonication effectiveness. In addition, lower liquid levels run the risk of damaging the ultrasonic generator and transducers. The Elmasonic S375 was especially designed to treat numerous small samples at the same time.

A Representative Sample Prep Cycle

Prepare the S375EL by adding water and a surfactant to the tank fill line, then turn the unit on and activate the degas mode for approximately 10 minutes. This both mixes the solution and drives off trapped air that impedes sonic action.

Follow established procedures for preparing samples. Place them along with the specified solvent in flasks or test tubes that in turn are positioned in the basket. Volumetric flasks can rest on the bottom of the basket; Erlenmeyer flask clamps and test tube holders are available as accessories. Note that sample containers only need to be partially immersed.

Lower the basket into the solution and select the Normal operating mode for a fixed ultrasonic frequency. Set the timer for the recommended sonication cycle. Set and remaining time are shown on the LED display.

Turn on the ultrasound.

Ultrasonic transducers produce millions of cavitation bubbles in the sonication bath. The sonic energy penetrates the walls of sample containers to induce ultrasonic cavitation. The cavitation bubbles implode on contact with the samples causing them to disperse and dissolve.

The S375EL will shut off at the end of the timed cycle.

For more information on using an ultrasonic bath for sample preparation contact our ultrasonic cleaning experts at 973-440-2191. You can also discuss equipment, processes and cleaning solution formulations to clean laboratory glass and other labware.


Your information is secure and will not be shared with a third party or spammed