Investigation of two digestion methods for preparation of architectural paints for measuring of heavy metals content

Architectural paints are used on different substrates in homes, schools, commercial buildings and etc. Paints will be toxic and pollutant because of entering the vapor phase and harmful substances to the environment. Since 1970s, the industrialized countries started to deduct restrictive laws to control the amount of heavy metals content used in their produced paints. Usage of acrylic paints as water-based new generation of architectural paints is increasing because of environmental issues and necessity of unemployment of organic solvents and harmful substances. This study describes the tests performed on architectural acrylic paints produced by some Iranian companies and also two samples from abroad. Samples were prepared according to two methods, including ASTM D3335 (using furnace) and using of sulfuric acid. Lead and cadmium as heavy metals were measured in prepared solutions by atomic absorption spectrometry. The results showed the same amount for lead and cadmium in both preparation methods. Furthermore, employment of sulfuric acid proved to be much faster than using furnace for digestion, in terms of time and energy saving, especially that nowadays measuring the heavy metals content is not welcomed by most of the manufacturers due to being considered as a time-taking procedure.