Title: Speciation of Se (IV) in marine sediments using neutron activation analysis
after co-precipitation with dibenzyldithiocarbamate (DBDTC) with phenolphthalein
Abstract
The determination of Se (IV) forms in marine sediments was performed on core
samples taken from a fairly polluted environment. Sediment core samples were sliced
into strata of between 2 and 3 cm thickness, dried at 60°C for 2 weeks and ground
to<200 mesh size prior to the analysis. The powdered samples were dissolved by
microwave digestion using a MDS-81D Microwave Digestion System. The
quantitative determination of Se (IV) was done by co-precipitating the Se (IV)
dibenzyldithiocarbamate complex with phenolphthalein (DBDTC-Pp) followed by
irradiation of the Se (IV) forms in a neutron flux of 4×1012 neutrons cm−2 s−1 from a
TRIGA Mk.II reactor at the Malaysian Institute of Nuclear Technology and Research
(MINT). The Se (IV) species concentrations were calculated using the 136.0 keV γrays of the 75Se by the comparison method. Standard reference materials, such as SL7 SRM supplied by IAEA was used to provide good quality assurance control. The
results showed that the concentrations of Se (IV) in the sediment samples are
between 3.93±0.05 ng g−1 and approximately 50.17±0.08 ng g−1. In general it was
found that the distribution of Se (IV) concentrations along the South Johore coastal
area showed some variations with locations and strata.