Lead (Pb) was used in paint to give color and durability to the paint. Lead is a heavy metal which is toxic to the body especially when the metal reaches the bloodstream. Since Pb was found to be toxic, the Consumer Product Safety Commission has placed a restriction of 100 ppm Pb in the paint. Home testing kits are available but these kits only test for the presence of Pb in paint and do not quantify it. Previous quantitative methods involve drying the paint and digesting it with concentrated nitric acid. The full digestion had to be boiled for about 4 hours. There are safety issues with boiling nitric acid because concentrated nitric acid is a strong oxidizer and a strong irritant. A safer method of digestion has been developed. Using a microwave assisted digestion; the samples were then diluted and measured using flame atomic absorbance spectroscopy (FAAS). A calibration curve was constructed and the concentrations of the samples were interpolated. Three experiments were completed. The first was to test if the paint would digest under the microwave parameters. The second experiment was to test for the proper dilution factors for the paint solutions in order to be measureable with the FAAS. This is important because the detector of the FAAS can only resolve up to 10 ppm Pb. The last experiment was to run the samples in an inductively coupled plasma-atomic absorbance spectrophotometer (ICP-AES) in order to validate the measurements done with FAAS.

Developing a safer, optimized method for determining Pb in paint

251st National Meeting (2016)

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