Table 2. Comparison of characteristics of different analytical methods for TC detection.

Main precursor	Sensor type	Synthetic method	Time and temperature	Linear range (µM)	LOD (µM)	QY%	Ref.
Ca(NO3)2, l-cysteine	CdSQDs	Chemical precipitation	4 h at 50 °C	15–600	7.78	69	66
Milk	N-doped CDs	Hydrothermal	4 h at 180 °C	2–200	0.6	10	67
O-phenylene diamine, glyoxal	Carbon dots (CDs)	Amine–aldehyde condensation	3 h at 25 °C	10–400	6	—	68
Sodium tungstate, cysteine	WS2QDs	Hydrothermal	10 h at 200 °C	0.1–10	0.039	9.6	55
Eu(NO3)3·6H2O citric acid melamine, formaldehyde	Eu-CDs	Hydrothermal	10 h at 220 °C	0–100	6.9	10.81	69
Waste tea, HNO3, Na2CO3	CDs	Chemical oxidation	6 h at ∼100 °C	0–7.2	0.09	2.47	70
Citric acid, TEOSa, APTESb	GQDs-SMIPsc	Sol–gel polymerization	0.5 h at 200 °C	15–120	3.55	_	71
AgNO3, ammonia, glucose, β-cyclodextrin	AgNPs	Chemical reduction	0.5 h, ∼100 °C	0.12–12.47	1.31	_	72
Zn(CH3COO)2·2H2O, BTCd	Zn-MOF	Solvothermal	16 h at 180 °C	0–17	0.014	_	73
1,4-Di-2-(5-phenyloxazolyl)-benzene (POB)	POB	No synthesis	≤10 min at 25 °C	0.5–40	0.143	84	This work
		Commercial dye

^aTetraethoxysilane.

^b3-Aminopropyltriethoxysilane.

^cGraphene quantum dots coated with silica molecularly imprinted polymers.

^d1,3,5-Benzenetricarboxylic acid.