United States.
Researchers at the University of Michigan have developed a new molecular gel recipe to achieve a more accurate paint lead test.
The test makes it easy to see if a piece of paint contains more than the regulated 5,000 parts per million of the poisonous metal that was banned since pigments in 1978. Government agencies use that threshold to define paint as a "lead base" and the Environmental Protection Agency requires that home test kits be able to differentiate whether they are above and below this base. However, these homemade kits have a wide margin of error and produce many false positives, the researchers say.
The new method:
- Consists of a vial containing paint thinner and a pinch of certain salts
- When it forms a gel when combined with the correct concentration of lead
- Users drop a paint chip, heating the mixture and waiting to see how the solution reacts
- If a gel is formed and the gel remains on top of the inverted vial, it is positive for at least 5,000 ppm of lead
- If the solution remains liquid and no gel is formed, there may still be some lead in the paint, but not enough to require special measures to maintain or dispose of it.
"The good thing is that it doesn't matter what color the paint is, and it's so simple: anyone can tell the difference between a liquid and a gel," said Gesine Veits, author of a paper published in the Journal of the American Chemical Society.
The test could help landlords and tenants better understand their level of risk. The researchers say it also pushes forward some exciting science. It demonstrates a more rational approach to making specific molecular gels, substances such as Jello that show promise for environmental cleaning, sensing and biomedicine applications.
Source: University of Michigan.
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