INTRODUCTION OF ORGANIC-SOLVENTS INTO INDUCTIVELY COUPLED PLASMAS BY ULTRASONIC NEBULIZATION WITH CRYOGENIC DESOLVATION

A two-step desolvation system for a continuous-flow ultrasonic nebulizer reduced the solvent load on an argon inductively coupled plasma (ICP). The aerosol was first heated above the boiling point of the solvent. Subsequently, solvent vapor was removed in two condensers kept at -10 °C and ≃-80 °C. No special plasma ignition procedures were required; a change of solvent did not cause plasma Instability. The plasma was stable to a forward power as low as 0.5 kW when methanol, acetone, acetonitrile, or ethanol was nebulized. The plasma could not be sustained while organic solvents were ultrasonically nebulized without at least partial desolvation. Detection limits for metals ranged from 0.2 μg L-1 for Fe to 5 μg L-1 for Pb. The detection limits for each element were approximately the same regardless of the organic solvent used and were comparable to those obtained during ultrasonic nebulization of aqueous solutions. With a forward power of 1.0 kW, molecular band emission from C2 was about 25 times less than when the aerosol was partially desolvated using a condensation temperature of -10 °C. © 1990, American Chemical Society. All rights reserved.