Mercury determination in fish samples by flow injection using gold electrodes made from CD-R’s

A new flow injection set up was developed for mercury determination by stripping chronopotentiometry.
The FIA system was based on using solenoid valves controlled by a computer. A flow cell was manufactured
with the gold working electrode made from a recordable compact disk (CD-R). The following operational
parameters were studied and optimized: sample flow rate, time of mercury deposition by electrolysis on the
electrode surface and current imposed for mercury dissolution off the working electrode. Mercury could be
measured within 5 - 100 ng/mL domain at a deposition time of 180 s. Detection limit was 0.1 ng/mL at
600 s deposition time. RSD for a concentration of 40 ng/mL mercury was 1.04% (n=6) under optimal
working conditions. . A concentration of 0.157±0.031μg mercury/g sample was found in a cod sample with
this method. Recovery degree of a known amount of mercury introduced in the analyzed sample was
96.2%.