Table 2.

Methods, precursors, and LODs of carbon dots produced from natural biomaterials for detection of Co²⁺.

Method	Precursors	Detection Limit (μM)	Reference
Hydrothermal	Straw	0.38	[66]
Microwave	Lime	1.63	[67]
Microwave	Kelp	0.39	[68]
Dry heating	Leek seed extract	1.7	This work