American chemists have pinpointed an unforeseen source of microplastics. Beyond the inherent harm caused by these particles, it has emerged that these substances are skewing the results of studies focused on microplastic concentrations in the environment. The culprit, press services from Michigan State University (MSU) report, turns out to be laboratory gloves.
MSU chemist Madeline Kloe explains that this issue has the potential to affect numerous microplastic investigations. Upon contact between samples and nitrile or latex gloves, stearic acid compounds can sometimes transfer into them. These compounds possess spectral characteristics extremely close to those of plastic particles, leading instruments to mistakenly identify them as microplastics.
The discovery of this problem occurred serendipitously. Researchers were engaged in analyzing air quality within the state of Michigan. The necessary samples were collected and subsequently examined using spectroscopy—a technique designed to accurately determine the chemical composition of particles. In several measurements, instruments indicated that the atmospheric microplastic levels were hundreds of times higher than the scientists had anticipated.
Experts suspected external contamination and began systematically investigating every piece of equipment and all consumable materials. The source of the false readings was identified: it was the nitrile gloves routinely employed during sample preparation. When hands move or rub, these gloves release microscopic particles and molecules of stearic acid salts, which possess spectral signatures almost identical to those of microplastics.
To definitively confirm this hypothesis, specialists tested an additional seven brands of laboratory gloves made from nitrile, latex, and other materials. The experiments confirmed that all of them are capable of generating thousands of false-positive signals, mimicking actual plastic particles.
This presents a complicated scenario: such interference frequently results in the overestimation of microplastic pollution across various media. Scientists are now calling for a reevaluation of current analytical methodologies.
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