Some heavy metal ions, for example, Pb2+ and Cd2+, are harmful
even at low concentrations, not only to the human beings but also
to the aquatic plants and animals due to their toxicity and nonbiodegradability
[1–3]. Their concentrations in coastal seawater are
much higher than that in the open ocean because of the enormous
amount of anthropogenic contamination. The determination of heavy
metal ions in coastal seawater is of great importance for the sustainable
development of marine production and environmental protection.
Generally, atomic absorption spectroscopy (AAS), inductively coupled
plasma–atomic emission spectroscopy (ICP–AES), and inductively
coupled plasma–mass spectrometry (ICP–MS) are routine methods
used widely for the determination [4,5]. However, the low sensitivity,
requirement of cumbersome instruments and high cost are inevitable
limitations, in particular for on-site performances [4,6]. In some case,
the key to remediate processes is the ability to determine heavy metal
ions on situ using simple devices, which can facilitate more rapid
decision-making [4]. Therefore, portable analytical systems are in
urgent need.