Researchers at the University of Michigan have discovered that common nitrile and latex lab gloves release particles resembling microplastics, potentially inflating pollution estimates. The study, led by Madeline Clough and Anne McNeil, traced contamination to stearates in the gloves during sample preparation. Switching to cleanroom gloves could reduce false positives significantly.
A University of Michigan study revealed that nitrile and latex gloves, widely used in labs, transfer stearates—soap-like substances added during manufacturing—onto tools and samples. These particles mimic microplastics under analysis, leading to overestimated levels in air, water, and environmental tests. The findings came from a project on airborne microplastics in Michigan, involving departments like Chemistry and Climate and Space Sciences Engineering. Madeline Clough, a recent doctoral graduate, noticed thousands of times more particles than expected while preparing sampling surfaces with gloved hands, prompting a contamination hunt that pinpointed the gloves as the source, according to materials from the university. Tests on seven glove types under typical lab conditions showed routine contact introduced around 2,000 false positive signals per square millimeter. Cleanroom gloves, lacking stearate coatings, released far fewer particles. Clough noted that such interactions affect various microplastics research methods. Anne McNeil, senior author and U-M professor of chemistry, macromolecular science, and engineering, and the Program in the Environment, emphasized the issue's gravity. 'We may be overestimating microplastics, but there should be none,' she said. 'There's still a lot out there, and that's the problem.' Clough added, 'We're searching for the needle in the haystack, but there really shouldn't be a needle to begin with.' The team, including collaborators like Andy Ault and Ambuj Tewari, developed techniques using microscopy and statistics to distinguish real microplastics from stearates, which look nearly identical to polyethylene. Published in RSC Analytical Methods, the research underscores the need for chemistry expertise in the field. McNeil said, 'This field is very challenging to work in because there's plastic everywhere.'