Robot helps detect contaminants in water after sewage treatment

Technology developed at the University of São Paulo increases the precision of chemical analysis and reduces the use of expensive toxic solvents. The immediate focus was on parabens, potentially carcinogenic compounds used in industry as preservatives.

By Cristiane Paião  |  Agência FAPESP – Researchers at the University of São Paulo (USP) in Brazil have developed a robot to automate the analysis of wastewater after sewage treatment, enhancing the precision of the results and reducing the use of costly and toxic solvents.

The research was conducted at the São Carlos Institute of Chemistry (IQSC-USP) during the doctorate of Marcio David Bocelli, with FAPESP’s support and supervision by Professor Álvaro José Santos-Neto. The results are reported in an article published in the journal Electrophoresis.

The purpose of the research was to detect the presence of parabens in samples of treated wastewater. Parabens are synthetic chemicals used as preservatives in a wide array of cosmetics, personal hygiene products, food products and pharmaceuticals, to prevent the growth of harmful bacteria and mold, for example. They cause allergies in some people, and there is evidence that they can disrupt hormones, harm fertility and reproductive organs, affect birth outcomes, and increase the risk of cancer. They are also harmful to aquatic animals.

“Water contaminated by parabens goes through the sewage plant, but unless the treatment removes them, they pass along to rivers and water sources, which they pollute. The existing wastewater analysis technique is manual and depends a great deal on the skill of the analyst. Some of our students take almost a year to master it. This is why we set out to automate the process,” Santos-Neto told Agência FAPESP.

The group used a well-known technique called dynamic single-drop microextraction but automated the syringe that performs the extraction process. The robot and the device that stabilizes and inserts the drops are being patented. A single droplet of solvent is sufficient for each analysis. In addition to reducing costs, the system increases the safety of laboratory workers.

“This type of analysis is almost always performed by traditional methods, using many liters of toxic and expensive solvents,” Bocelli said. “There has to be a paradigm shift if this project is to become a reality, and that depends on the stance taken by institutions and private enterprise. They need to understand the benefits associated with miniaturization and robotization, especially cost reduction and environmental protection.” 

Process of analysis

The research was conducted as part of the Thematic Project “Single-drop chromatography and its coupling to mass spectrometry: instrumental strategies, development of materials, automation and analytical applications”, for which the principal investigator is Fernando Mauro Lanças. The other authors of the article are Deyber Arley Vargas Medina, who is also funded by FAPESP, and Julie Paulin García Rodriguez. All five co-authors are affiliated with IQSC-USP.

According to Santos-Neto, one of the group’s primary aims is to develop novel equipment that will assist routine chemical analysis. The reason for focusing on parabens in this study was that they can be a human and animal health hazard.

Advances are needed in different scientific areas to demonstrate the link between parabens and cancer, he said, but the fact is that they can behave as pollutants, and alternatives should be found in the service of environmental protection.

“There are cases where treatment does actually remove these contaminants. Wastewater can be cleansed of several micropollutants, and certain compounds are partially removed. Our research aims to determine their real impact. They’re considerably diluted when the treated wastewater is discharged into rivers, but chronic exposure, even at very low levels, can also cause problems,” he said.

Advantages of automation

The equipment was created to help monitor water quality by determining the amounts of contaminants left after treatment and extracting them from the samples analyzed. The automation was based on Arduino, an open-source electronics prototype creation platform. According to Santos-Neto, the same approach can be used to analyze other pollutants.

A prototype of the robot that extracts parabens and other components on a laboratory scale is ready, but investment in commercialization will be required once the patents are approved. “We’ve completed the proof-of-concept stage. The robot performs well. We now need interested companies to come forward,” Santos-Neto said.

The article “Determination of parabens in wastewater samples via robot-assisted dynamic single-drop microextraction and liquid chromatography-tandem mass spectrometry” is at: analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/elps.202100390.