SOLID-PHASE EXTRACTION OF ORGANOTIN COMPO UNDS IN SEAWATER

For the speciation of ultra trace organotin compounds, a technique for separation and preconcentration, such as organic solvent extraction, is useful. However, a solid phase extraction (SPE) is preferable from the viewpoint of environmental pollution. The SPE of comparatively lar ge amounts of organotin compounds in seawater has been developed using a polymer of styrene derivative/metacrylic ester as a solid phase sor bent. The sorbent (500 mg) was put into a 8 ml reservior. Recovery of organotin was measured by AAS. In pure water containing organotin comp ounds (TBT, TPT) there was almost 100% recovery in the range of pH 0.2 5 similar to 8.0, while in the 2.45% sodium chloride solution (equival ent to the sodium chloride content in seawater) the recoveries decreas ed to about 50 similar to 60%. This problem was resolved by adding met hanol. To prepare sample solutions, methanol was added to be 50% (v/v) , in artificial seawater samples containing organotin standard solutio ns and the pH was adjusted to 0.5 with nitric acid. The water samples were forced through the cartridge at a flow rate of 4.5 similar to 5.0 ml min(-1). Elution was by gravity flow of 10 ml methanol. Recoveries of TPT and TBT were more than 90%, while those of DPT and DBT were ab out 30 and 60%, respectively.