Table 6.

SPR sensors for Cu(II) detection.

Detection Range	Receptor	Reference
3.9 µM–0.1 mM	Self-assembled monolayer (SAM) d,l-penicillamine	This work
0.1 μM–1.0 mM	2-aminoethane thiolhydrochloride and 6-aminohexane thiolhydrochloride	[29]
0.15mM–7,9 μM	hexadecyltrimethylammonium bromide/nanocrystalline cellulose/graphene oxide	[13]
7.9 μM–1.6 mM	MMW chitosan (glutaraldehyde-crosslinked)	[30]
1.5 μM–not given	Schiff base derivative	[31]
1.6 nM–1.6 μM	Mercury-free gold electrode (SPR combined with ASV)	[32]
1.0 pM–10 mM	Squarylium dye containing polymeric thin-film	[33]