DETERMINATION OF BIOGENIC SILICA IN MARINE SEDIMENTS – SELECTION OF PRETREATMENT METHOD AND EFFECT OF SAMPLE SIZE
To optimize the alkaline leaching technique for quanufication of biogenic silica in marine sediments, different pretreatment methods were evaluated. Marine sedimenrs were pretreated with fumes of concenrrated hydrochloric acid, hydrochloric acid solutions or/and hydrogen peroxlde prior to extracrion of biogenic silica. The acid pretrearment removes carbonates and meral oxides coaung the biogenic silica surface, which may prevent dissolution. A pretreatment with fumes of concenrrated hydrochloric acid gave a better recovery of biogenic silica from sediments and a better reproducibility of the analysis than untreated samples. These results were obtained with different types of sediment. The pretreatment method with fumes of hydrochloric acidwas found not to dissolve alumino silicares in such a degree that it would inrerfere with the determinadon of biogenic silica. “Complete abstract not presented.”