Table 2.

Comparison of the reported methods for Fe³⁺ and Cr₂O₇²⁻ using Ln-MOFs.

Ln-MOFs	Detect Ion	LOD (M)	Ratio Fluorescent Probe	Linear Range	References
Eu0.075Tb0.925-MOF	Fe3+	2.71 × 10−7	Dual emission	10–100 μM (R2 = 0.99919, R2 = 0.99937)	This work
	Cr2O72−	8.72 × 10−7
Eu-MOF; Tb-MOF [Eu/Tb, 4,4′-(((5- carboxy-1,3-phenylene)bis(azanediyl))bis(carbonyl)) dibenzoic acid]	Fe3+	1 × 10−5	Single emission	0–1.0 mM (R2 = 0.9021, R2 = 0.9752)	[47]
	Cr2O72−	8.94 × 10−5
Eu-MOF [Eu, 5-(2′,5′-dicarboxylphenyl) picolinic acid ligand]	Fe3+	5.7 × 10−7	Single emission	0–50 μM (R2 = 0.9948, R2 = 0.9979)	[48]
	Cr2O72−	4.2 × 10−7
Tb-MOF [Tb,H3BTB]	Fe3+	1 × 10−5	Single emission	-	[49]
Eu-MOF [Eu, 2-aminoterephthalic acid 1,10-phenanthroline]	Fe3+	4.5 × 10−5	Single emission	0–0.25 mM (R2 = 0.992)	[50]
Tb-MOF [Tb, 2-(2-carboxyphenoxy)terephthalic acid]	Fe3+	2.0 × 10−4	Single emission	10−4–10−3 M (R2 = 0.978)	[51]
Eu-MOF [Eu, 2-(3′,4′-dicarboxylphenoxy)isophthalic acid, 4,4′-bis(imidazolyl) biphenyl	Fe3+	1.32 × 10−5	Single emission	0–10−5 M (R2 = 0.9885, R2 = 0.9927)	[52]
	Cr2O72−	1.01 × 10−5