ICP - Ultrasonic Nebulizer

The ultrasonic nebulizer is an atomization device that is popular for use when enhanced sensitivity is required for analysis applications.

The apparatus consists of a piezoelectric crystal transducer, which is driven by an ultrasonic generator operating at a frequency of 200 kHz to 10 MHz.

Sample is delivered to the front surface of the transducer through tubing from a peristaltic pump at a flow rate of up to 1 mL/min.

An aerosol is formed by the standing longitudinal waves at the surface of the transducer crystal. When the amplitude of the wave is large enough to disrupt the film of solution deposited on the surface of the transducer, an aerosol is generated, which is removed from the nebuHzer by the argon flow.

Delivery of sample at a rate of 1 mL/min yields an analyte transport efficiency of about 20%.

By reducing the delivery rate of sample to the transducer, high transport efficiencies can be obtained. Using a sample delivery rate of 5-20 uL/min, an aerosol transport efficiency of close to 100% can be obtained. Between samples, the surface of the transducer is flushed with large quantities of water to remove all traces of the previous sample.
The aerosol production rate is high and is independent of aerosol carrier gas flow rate, more sample is transported to the plasma at lower injector gas flow rates than that obtained with conventional pneumatic nebulizers.

This results in enhanced sensitivity obtained using this nebulizer, with a corresponding improvement in detection limits for essentially all elements measured.