. 2024 Sep 13;40(38):20204–20218. doi: 10.1021/acs.langmuir.4c02568

Table 2. Value of the Parameters of the Langmuir Fit (eq 3), Together with the Sensitivity to Analyte Concentration S_c and the LOD as Expressed by eq 1 and 2, Respectively; the Parameters Are Related to the Optical Sensing of the HMIs by Both Bare Gold Thin Films and Gr/Au Heterostructures; the ParameterS_e Represents the Sensitivity Enhancement after Graphene Transfer on the Gold Layer.

SPR Chip	HMI	S_c (°/ppm)	S_e	LOD (nmol L^–1) (ppb)	Δθ_max	K (L mol^–1)	R²
Au	Hg²⁺	1.4	–	25	0.044	7.2 × 10⁶	0.996
	Hg²⁺	1.4	–	5.2	0.044	7.2 × 10⁶	0.996
	Pb²⁺	0.9	–	38	0.057	3.5 × 10⁶	0.955
	Pb²⁺	0.9	–	7.9	0.057	3.5 × 10⁶	0.955
	Cd²⁺	3.8	–	16	0.032	1.5 × 10⁷	0.994
	Cd²⁺	3.8	–	1.8	0.032	1.5 × 10⁷	0.994
Gr/Au	Hg²⁺	9.8	7.0	3.4	0.080	3.1 × 10⁷	0.980
	Hg²⁺	9.8	7.0	0.7	0.080	3.1 × 10⁷	0.980
	Pb²⁺	3.4	3.8	9.7	0.072	1.1 × 10⁷	0.966
	Pb²⁺	3.4	3.8	2.0	0.072	1.1 × 10⁷	0.966
	Cd²⁺	4.7	1.2	13	0.062	8.5 × 10⁶	0.970
	Cd²⁺	4.7	1.2	1.5	0.062	8.5 × 10⁶	0.970