Can microplastics be measured using Raman Microscopy?

Microplastics are considered a major environmental concern because they can be present in various bodies of water across the world. They can be found in seawater, freshwater, and even in bottled water.

Some of the most often found microplastics are polypropylene and polyethylene. Polyethylene is commonly used to make plastic bags and polypropylene can be often found in food packaging material.

Raman Microscopy is one of the ideal methods for measuring these particles. This technique can be used for chemical or molecular analysis of unknown compounds in a small area, down to less than a micron.

Tools for Microplastic Analysis using Raman Microscopy

The NRS-4500, a Raman microscope, can measure small samples that have a size of around one micrometer. These samples can be placed in the microscope using a glass slide. 

The plastics for this measurement are microplastics collected in the South Florida region. These samples were washed thoroughly to avoid any influence on the measurement.  

The laser that we used was 785nm. This laser can produce less fluorescence. We also use less power from the laser so this decreases the chance of damaging the sample when performing a measurement.

Results

Once the measurement is completed, we can see that the peaks come out very nicely in a very short time of collection. Next, the spectrum then is sent to a search algorithm that is going to identify what is the possible material. The sample was identified as polypropylene.