Analysis and Determination of Polyphenol and Iron Concentrations in Some Selected Seaweed Species using UV-Vis

Abstract

Seaweeds readily absorb heavy metals that are present in their environment, because of this; they are an effective way of monitoring heavy metal pollution in an area. The metal that is absorbed can be damaging to the seaweed cell walls. Seaweeds have evolved over time to have excellent antioxidant systems to combat this damage. One antioxidant they produce is polyphenol, a chemical molecule containing many phenol rings that bind to metals and keep them from the damaging the cell walls. They have been shown to be linked to the health benefits of red wine, fruit and vegetables. Samples of different species of seaweed from the Bangor area were collected, processed and analysed for their iron and polyphenol concentrations. Samples were collected from multiple points along the Bangor coastline, they were dried and processed into a fine, dry powder. The iron concentrations were analysed by Atomic Absorption Spectroscopy after digestion by HNO3. Different species were analysed for the iron and polyphenol content. The whole of the algae was analysed, as well as the nodules and the rest (stipe and blades). The polyphenol concentrations were analysed by a colourimetric assay using the Ragan and Glombitza method and quantified by UV/Vis spectroscopy. Different species were tested in order to see if the concentrations of iron and polyphenol change between species. Different parts of the seaweed were also tested to see where the higher concentrations of the metals were located. Iron concentration statistically significantly changed between all species with the concentrations ranging from 58.0 ± 3.5 mg/Kg to 796.0 ± 10.6 mg/Kg. The Polyphenol concentration changed statistically significantly between some species, but statistically not significant between others. Polyphenol concentration ranged from 63.7 ± 0.3 mg (g dw)-1 to 202.1 ± 6.7 mg (g dw)-1.