AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
A Piezoelectrically Actuated Nebulizer for Inductively Coupled Plasma (ICP) Spectrometry
SANAZ ARABZADEH, Hamid Badiei, Kaveh Kahen, Javad Mostaghimi, PerkinElmer Inc.
Abstract Number: 336 Working Group: Instrumentation and Methods
Abstract Pneumatic nebulization of liquid samples is the most commonly used method of sample introduction in ICP atomic emission spectroscopy and mass spectrometry. Their performance, however, is plagued by poor sample transport efficiency due to the wide size distribution of primary aerosol and the need to remove large droplets. In addition, the nebulizer gas used to generate the primary aerosol is also used to transport the droplets to the plasma, which dictates a compromise between the nebulization efficiency and the residence time in the plasma.
Unlike a pneumatic nebulizer, a piezoelectrically actuated nebulizer generates the sample aerosol by vibrating a meshed membrane situated behind a typical injector tube of an ICP torch. The piezo nebulizer generates a narrow distribution of droplets (6-10 microns dia.) which can be introduced directly into ICPs.
In addition to transport efficiency, the characteristics of the electronic nebulizer approach those of an ideal sample introduction system in many aspects, including: a) the use of an active mechanism of aerosol generation that yields a narrow size distribution droplets with a low initial velocity (<5 m/s), b) unlinking the parameters that affect both the aerosol generation and transport processes, which allows independent optimization of nebulizer and plasma parameters to achieve the best analytical performance, c) eliminating signal noise sources such as those originating from peristaltic pump pulsations, d) improved long-term signal stability and short term precision, e) providing a dynamic adjustment of the amount of aerosol generated (by controlling the duty cycle in the drive waveform) and allowing multipoint calibration curves to be constructed from a single standard solution, and f) high tolerance to matrices with high dissolved solids in a variety of acidic solutions.
Design and development of the piezo nebulizer for ICP sources are discussed in detail and the performance characteristics of the system are presented.