Instrumentation
Mercury content in all samples was analyzed by cold vapour
atomic absorption spectrometry (CVAAS) using a mercury analyzer
(Model MA 5840E, Electronics Corporation of India Ltd.,
Hyderabad, India). Matrix matched standards were used for
quantification of mercury.
A homemade gold trap was introduced to further enhance the
sensitivity of determination of mercury. The gold trap was constructed
using a 0.2 g of 0.3mm diameter gold wire, which was
wound on a platinum mesh. This was inserted into a quartz tube
(4mm i.d.). Ar gas freed from any traces of mercury impurity
by passing through a second gold trap was used to flush mercury
vapors from the reaction cell on to the gold trap. Then the
concentrator trap was removed and connected to the mercury
analyzer. The trap was inserted into a 22-guage nichrome wire
coil which was rapidly heated to 750 ◦C to release the mercury
for analysis by CVAAS.