METHOD DEVELOPMENT FOR THE DETERMINATION OF TIN IN A MARINE SEDIMENT AND A PRELIMINARY STUDY OF TIN

Organotin compounds are used as fungicides and antifouling agents, which are incorporated into paints for use in sea vessels. These compounds have been found to be a threat to the environment. Method development for the determination of total tin in marine sediments by Zeeman GFAAS was studied. The optimum pyrolysis and atomization temperatures for tin analysis were 1100ºC and 2300ºC, respectively. When different matrix modifiers were evaluated, a mixture of NH4H2PO4/Mg(NO3)2 and Mg(NO3)2 alone produced the optimum tin signal. No significant effect on the tin signal was observed when using HNO3 as a diluent. The extraction of total tin from marine sediments was best performed by sample digestion with 6 M HCl and diluting the sample extracts with 1 % HNO3. Finally, the tin analytical and extraction method developed in our investigation was used to determine tin content in marine sediments from La Paz, Baja California Sur, Mexico. Tin concentrations in La Paz Bay area ranged from 320 to 5570 µg Sn/Kg of sediment (dry-weight)