Table 1.

Summary of some fluorescent probes for Cu²⁺ sensing.

Probe	Response Time (min)	Response Interval (μM)	LOD (μM)	Reference
CDSe	5	0.005–100	0.005	[50]
CdSe/Zns@CDs	—	1–100	1	[77]
CDs from sago waste	—	0–47	7.78	[76]
CDs from grass	10	5 × 10−5–50	0.001	[82]
CDs from peanut shell	10	0–5	4.8	[83]
CDs from MS	15	0–10	0.23 × 10−3	[81]
CDs from CA	—	0.37–2.5	0.63	[85]
N–CDs from EDA/P2O5	—	10–400	10	[87]
N–CDs from D-glucose/EDA	10	10–100	1.8	[84]
N–CDs from CA/NaBH4/PEI	<1	0–80	5.3	[79]
N–CDs from CA/PEI	—	0.3–1.6	0.12	[80]
N–CDs from CMC/LPEI	1	1–30	0.9	This work

Note: MS: mesoporous silica, CA: citric acid, P₂O₅: phosphorus pentoxide, EDA: ethylenediamine, NaBH₄: sodium borohydride, PEI: polyethyleneimine.