Slurry Atomization dc Plasma Emission Spectrometry and Laser Diffraction Studies of Aerosol Production and Transport

Abstract

A clog-free Babington slurry nebulizer system is presented for direct current plasma (DCP) emission spectrometry. The DCP is unique in that the torch tip opening at the entry point into this plasma is presently ∼5 times wider than that of the inductively coupled plasma and ∼10 times wider than that of premixed flame burner slots. The combination of this enlarged DCP torch tip opening and a Babington slurry nebulizer results in an overall system for spectrochemical analysis that is virtually unrestricted as to the direct nebulization and aerosol transport of homogenized solid samples such as animal tissue. Beef liver is briefly homogenized for 2 min and then directly nebulized into the plasma. A sample may be nebulized continuously without torch tip clogging. This eliminates the need for transient nebulization and allows for extended electronic integration times as well as wavelength scanned, spectral background correction procedures. Elements such as Cu, Zn, Ca, and P are detected in liver tissue within less than 10 min from the time the unprepared solid sample is received in the laboratory. The effects of Babington gas orifice diameter, argon flow rate, and sample consumption rate are studied. The DCP is found to have a remarkably wide range of gas flow rates acceptable for nebulizer operation. The use of near forward laser Fraunhofer diffraction is reported for the direct measurement of droplet size distributions on a nonintrusive basis as the aerosols emerge from spray chambers of spectrochemical interest.