Laboratory Analysis

After disembarkation the samples are analysed in a laboratory in collaboration with Aalborg University, Department Of The Build Environment.

Microplastics in the marine environment are transported by means of physical processes such as surface drifting, vertical mixing, beaching, and settling. These physical processes are driven by the properties of the ocean and its currents, gyres, and physical oceanographic characteristics such as salinity and temperature. The transport of microplastics is also influenced by the particles themselves, as their size, shape, and physical characteristics affect the way they are transported.

Therefore every plastic particle collected is analysed in the laboratory at Aalborg University, Department Of The Build Environment. All particles are photographed and individually counted and weighed and their polymer type are analysed using infrared spectroscopy by an ATR-FTIR.

All particles are individually weighed using a weight scale to 0,00000 grams. Particles weighing below 0,00000 grams can not be weighed using this weight scale and their weight is therefore calculated using a mathematical calculation.

All particles are individually photographed. The plastic particles above 1 mm in size were photographed using this protocol. The plastic-looking particles are picked out under an optical microscope using forceps. The plastic sample is carefully placed onto a white background surface, ensuring an even spread of particles over the area. Using forceps, the particles are separated from each other, not touching each other. A size reference is on the background surface. An image is taken of the contents of each of the samples 20-30 cm away from the surface. The images should be taken near a light source, after the plastic has dried. Ensure that all particles are captured on the image and there is minimal interference from light and/or shadows. The sample is photographed including the date and time and the specific sample number and letter. Plastic particles below 1 mm are photographed individually using a stereo microscope.

All particles are analysed using ATR-FTIR-spectrometer for polymer identification. Infrared spectroscopy offers reliable identification of polymers.

Plastics are a wide range of synthetic materials with polymers as a main ingredient which makes it possible for plastics to be moulded and pressed into solid objects. Plastics are usually classified by the chemical structure of the polymer's backbone and side chains. The vast majority of these polymers are formed from chains of carbon atoms, with or without the attachment of oxygen, nitrogen or sulfur atoms.

Although nearly every type of commercial plastic is present in marine debris, the floating components are dominated by polyethylene and polypropylene because of their high production volumes and their buoyancy. Low-density polyethylene is commonly used to make plastic bags or six-pack rings; polypropylene is commonly used to make reusable food containers or beverage bottle caps.