Lab Gloves Have Been Skewing Microplastics Data for Years

University of Michigan researchers Madeline Clough and Anne McNeil discovered that standard nitrile and latex lab gloves shed stearate particles that generate approximately 2,000 false positive signals per square millimeter, closely mimicking microplastics under spectroscopy. The contamination occurs because stearates, soap-like substances added during glove manufacturing, are chemically similar to plastics like polyethylene and transfer onto lab equipment during routine handling. The finding, published in RSC Analytical Methods, suggests years of microplastics measurements in air, water, and environmental samples may be significantly overestimated. The researchers recommend switching to cleanroom gloves and have developed methods to separate true microplastics from glove contamination, potentially allowing scientists to reanalyze historical datasets for more accurate pollution estimates.

Lab Gloves as a Source of Contamination in Microplastics Research

• ▪Nitrile and latex gloves introduced around 2,000 false positive signals per square millimeter on average during testing.
• ▪University of Michigan researchers Madeline Clough and Anne McNeil recommend using cleanroom gloves, which release far fewer particles than nitrile and latex gloves.
• ▪Anne McNeil is a University of Michigan professor of chemistry, macromolecular science and engineering, and the Program in the Environment.

Discovery Process and Experimental Investigation

• ▪The University of Michigan glove contamination experiments recreated typical lab conditions, such as a gloved hand touching filters, microscope slides, and other equipment used during analysis.
• ▪The airborne microplastics project involved researchers from multiple University of Michigan departments, including Chemistry, Statistics, and Climate and Space Sciences Engineering.
• ▪The University of Michigan microplastics glove contamination research was published in RSC Analytical Methods.
• ▪Madeline Clough is a recent doctoral graduate from the University of Michigan.
• ▪The University of Michigan research team analyzed air samples using light-based spectroscopy to identify the types of particles present.
• ▪The University of Michigan research team used air samplers equipped with metal surfaces that collect material from the atmosphere to capture particles.
• ▪The University of Michigan microplastics glove contamination research was supported by the U-M College of Literature, Science, and the Arts' Meet the Moment Research Initiative.
• ▪Madeline Clough and Anne McNeil worked with collaborators including chemistry professor Andy Ault and graduate students Rebecca Parham and Abbygail Ayala to collect air samples.
• ▪When Madeline Clough reviewed the results from the air sampling surfaces, the number of detected microplastics was thousands of times higher than expected.
• ▪Madeline Clough wore nitrile gloves while preparing the sampling surfaces, following standard practice.
• ▪The University of Michigan researchers tested seven different types of gloves, including nitrile, latex, and cleanroom varieties.

Methods to Distinguish Real Microplastics from False Positives

• ▪The methods developed by Madeline Clough, Anne McNeil, Eduardo Ochoa Rivera, and Ambuj Tewari could allow scientists to revisit earlier datasets and produce more accurate estimates of microplastics.
• ▪Madeline Clough and Anne McNeil, working with graduate student Eduardo Ochoa Rivera and statistics professor Ambuj Tewari, developed methods to separate true microplastics from glove-related contamination.

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