Keeping Up With the Drive for Microplastics Detection

Headlines regarding the presence and potential hazards of microplastics to the environment, humans and animals are becoming all too common and it would appear the more we look, the more we find. Accordingly, the numbers of studies around microplastics are soaring as we try to get a handle on the magnitude of the problem, the danger posed in real terms and how we deal with it.

To facilitate this work, analysts need accurate, fast and reliable means to detect and identify microplastics in samples, an area which has proven problematic for a multitude of reasons. This is likely to become increasingly important, however, as the minds of regulatory bodies and those tasked with keeping us safe turn to the prospects of imposing limits and regulations on microplastics in anything from drinking water to the air we breathe.

We spoke to Geoff Winkett, vice president of molecular spectroscopy at Agilent, and Michel van den Berge, senior marketing director for molecular spectroscopy at Agilent, about the issues posed by microplastics analyses and how molecular spectroscopy is rising to the challenge.

Karen Steward (KS): Concerns regarding microplastics are leading to increased research and analysis in this field. Can you tell us about some of the difficulties with microplastics analyses?

Geoff Winkett (GW): Microplastics have certainly received a lot of press over the last few years. I think we're all concerned about what's going into our drinking water and our food supply from plastics in our oceans and rivers. It's interesting that the strength of public concern means this field has been almost consumer led. It's driving governments to think that we need to start regulating this market and regulating what type of plastics and how much plastic we can have in our food or our water. Now, the market is getting to the point where many regions are starting to regulate.

But the techniques that have typically been used in this area, whether it be single point microscopes or Raman imaging-based techniques, can be labor intensive and slow to run the samples through. In this market, throughput is essential to getting as many samples though as possible. Once a testing method gets through regulatory approval, the big contract labs will get involved and throughput and speed are their priority.

KS: How is Agilent helping to address the analytical needs for microplastics

GW: We introduced the Agilent 8700 laser direct infrared (LDIR) chemical imaging system to the market a couple of years ago. It’s essentially a one-stop shop solution for microplastics. Once a technician has written a method and saved it, they can simply run multiple samples through the system without any manual input or intervention. The quantum cascade laser (QCL) technology that's embedded in this product, combined with innovative software and the optical interface, means that the speed at which we can run samples is significantly quicker than many of the other solutions on the market and therefore, the throughput is considerably higher. We’re at a good place now with the LDIR and finding excellent acceptance, particularly from people moving towards the regulation of microplastics that require the speed and throughput of those measurements.

In terms of the microplastic market, as we get into regulations, there's certainly going to be a significant demand for testing. Globally, the water testing authorities are going to have to investigate further and the 8700 LDIR is a really cool tool for microplastics analysis.

KS: Are there any microplastic types that are more challenging than others

Michel van den Berge (MvdB): Yes, there are, and that's where libraries come in. Each plastic has its own distinct spectra, and we have a library of these spectra that the instrument can check the unknown sample against. The instrument searches the library and identifies what kind of polymer it is. But the plastics that are in the oceans, or in the rivers haven't been there for just a few hours, they may have been there for days, months or years. This is what is called a weathered plastic, and the spectrum from a weathered plastic can be very, very different from that given by the original polymer when it was fresh. Therefore, we have multiple initiatives to also have different versions of the libraries including these weathered versions of the plastics available for customers, so they can make correct identifications.

GW: Moving forwards, machine learning may support the development of some of these libraries. I'm not sure we've fully seen where this market is heading yet, especially as there are so many unknowns and complexities around microplastics.

KS: Do you see LDIR as a standalone solution to microplastics testing or do you think other technologies also play an important role?

MvdB: As well as spectroscopy, other techniques like gas chromatography-mass spectrometry (GC-MS), are being used for microplastic detection but for different purposes. Scientists are investigating the impacts of microplastics themselves on the body, that’s ongoing. But in addition, there may be pollutants and other harmful compounds attached to the microplastic polymers. The plastics themselves may or may not be hazardous but sometimes what they could bring with them poses a hazard, so it’s important to have ways of detecting these too. Customers are therefore using multiple technologies for the identification of the microplastic particles.

Geoff Winkett and Michel van den Berge were speaking to Dr. Karen Steward, Senior Science Writer for Technology Networks.