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Gossman Consulting, Inc.

Presented at the 1983 Pittsburgh Conference

THE DETERMINATION OF METALS IN PAINT AND PAINT WASTES USING ATOMIC ABSORPTION AND EMISSION SPECTROSCOPY

Authors:

David G. Gossman Jim Woodford Craig Cape
SYSTECH Corporation   SYSTECH Corporation   SYSTECH Corporation

David Gossman, Jim Woodford and Craig Cape are now all with Gossman Consulting, Inc.

The concentration of certain metals such as lead, chromium, zinc, titanium, barium and iron in paint and paint wastes has significant bearing on the use and disposal of such materials. The traditional method for determining those metals involved the drying or ashing of the paint, then acid digestion, and finally the determination using atomic absorption equipment. This is a long and tedious process prone to numerous handling errors. The need for a high speed method to determine these metals at relatively high concentrations prompted the development of a solvent-based method of sample preparation taking only 1 to 2 minutes.

The sample is prepared by dilution in a mixture of appropriate solvents which is then thoroughly agitated. Standards are prepared by diluting oil based metals standards, used in the analysis of wear metals, in the same solvents. The determination is made using a Perkin-Elmer 5000 atomic absorption spectrophometer. Because of the hotter and richer flame associated with the use of an organic-based solvent matrix, atomic emission becomes a significant alternative in the case of some of these metals. The use of a nitrous oxide/acetylene flame and atomic emission spectroscopy eliminates the need for hollow cathode lamps while at the same time allowing determinations as low or, in some cases, lower than the traditional absorption method.

In conclusion, the use of highly automated equipment and this extremely fast sample preparation technique allows the determination of six or more different metals in a single sample in less than 30 minutes from the time the sample arrives in the lab.