The magnetic solid-phase extraction procedure was described
as follows: 10 mg of prepared SH-Fe3O4/Cu3(BTC)2 adsorbent was
added to 10 mL of spiked sample solution adjusted at pH 6 using
1 mol L1 sodium hydroxide or 1 mol L1 nitric acid. The solution
was stirred for 15 min to facilitate the adsorption of lead on to
the surface of SH-Fe3O4/Cu3(BTC)2. The magnetic sorbent was collected
using an external magnet and supernatant water was
decanted. Finally, the extracted analyte was desorbed with
2.0 mL HNO3 and injected into the FAAS for analysis.