2.1. Reagents and solutions
All the reagents were of analytical grade and all the solutions
were prepared with deionized water processed in Milli-Q system
(Millipore, Bedford, USA). Multi-wall CNTs (with 6–9 nm of e.
d. 5 mm of length) were purchased from Sigma Aldrichs (Steinheim,
Germany). BSA, glutaraldehyde and sodium borohydride
used in the CNT's coating were acquired from Sigma Aldrich. The
Pb2þ standard solutions were prepared by dilutions of
1000 mg L1 Pb2þ stock solution purchased from Sigma Aldrich.
Nitric acid, as well as acetate and phosphate buffer solutions, used
in the flow system, were acquired from Sigma Aldrich.