Facile and High-yield Synthesis of N-doped Carbon Quantum Dots from Biomass Quinoa Saponin for the Detection of Co²⁺

Figure 8

(a) The selectivity test of CQDs (0.8 mg/mL) for Co²⁺ against different metal ions (excitation wavelength = 390 nm); (b) FL photographs of CQDs with various metal ions under the UV-lamp (λ = 365 nm); (c) FL emission spectra of the CQDs (0.8 mg/mL) upon exposure to various concentrations of Co²⁺ (from top to bottom: 0, 1, 2, 3, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100, 200 µM) in aqueous solution excitation at 390 nm; (d) The calibration curves and linear equation for the FL quenching ratio and concentration of Co²⁺.

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