Imptox scientists developed a fast and highly efficient method to isolate microplastics from human stool samples, opening new possibilities for large-scale biomonitoring and exposure research. 

Tracking microplastics in human matrices is a little like searching for tiny needles in an extraordinarily messy haystack. Scientists know these particles are entering our bodies through food, water, and air, but detecting them reliably in biological samples remains one of the biggest challenges in microplastics research. 

Now, a group of Imptox researchers led by Tanja Ćirković Veličković  and her team from the University of Belgrade in collaboration with the Srebrnjak Children’s Hospital has developed a new protocol that could help make this task far more reliable, efficient, and accessible. Published in May 2026 in the Journal of Hazardous Materials Advances, the study introduces a method for extracting microplastics from human faecal samples with remarkable precision and consistency.  

The paper tackles a central obstacle in the field: stool samples are extremely difficult to analyse because they contain large amounts of cellulose-rich biological material that can interfere with the identification of tiny plastic particles. 

An Unexpected Chemical Ally 

To overcome this, the researchers turned to an unexpected chemical ally: Schweizer’s reagent, a copper-based solution traditionally used to dissolve cellulose. While the reagent has previously been used in wastewater analysis, this is the first time it has been successfully applied to complex biological matrices such as human faeces. 

The results were striking. The optimized protocol removed more than 99.8% of the biological matrix while still recovering around 98% of the microplastics intentionally introduced into the samples during testing. Just as importantly, the process preserved the chemical integrity of the particles, allowing scientists to accurately identify them using µ-FTIR spectroscopy, one of the key analytical techniques in microplastics research. 

From the Laboratory to Real Samples 

The team then applied the protocol to stool samples collected from children in different geographical regions in Croatia. Microplastics were detected in seven out of fourteen samples, with concentrations ranging from 1.18 to 7.25 particles per gram of faeces. Most of the detected particles were polyethylene - one of the world’s most widely produced plastics - and fragments were the dominant particle shape. 

Toward Standardized Biomonitoring 

Although the study was not designed to assess health risks, the findings demonstrate that the protocol works under real-world conditions and can support future biomonitoring studies investigating human exposure to microplastics. That matters because one of the major bottlenecks in the field today is the lack of standardized methods. Different laboratories often use different extraction and analysis procedures, making it difficult to compare results across studies. A robust, reproducible, and cost-effective workflow could therefore play an important role in harmonizing research efforts internationally. 

The newly developed approach also offers practical advantages over conventional workflows. According to the researchers, it is faster, more economical, and easier to reproduce while maintaining high analytical performance. These characteristics are particularly important if scientists hope to conduct large-scale studies involving hundreds or thousands of human samples in the future. 

Reference: 

Miloš Ilić, Tamara Mutić, Dragana Stanić-Vučinić, Ivana Banić, Mirjana Turkalj, Jelena Mutić, Tanja Cirkovic Velickovic, Efficient Schweizer’s reagent-based protocol for microplastic extraction from fecal samples: Toward standardized human biomonitoring, Journal of Hazardous Materials Advances, Volume 22, 2026, https://doi.org/10.1016/j.hazadv.2026.101184.