Electronic Supplementary Material s77

Electronic Supplementary Material

Graphene quantum dot coupled with gold nanoparticle based “off-on” fluorescent probe for sensitive and selective detection of L-cysteine

Shan Huanga,b, Lumin Wanga, Chusheng Huanga, Baoqing Hub, Wei Sua, Qi Xiaoa,b,*

a College of Chemistry and Materials Science, Guangxi Teachers Education University, Nanning 530001, P. R. China

b Key Laboratory of Beibu Gulf Environment Change and Resources Utilization (Guangxi Teachers Education University), Ministry of Education, Nanning 530001, P. R. China

* Corresponding author. Tel.: +86 771 3908065; Fax: +86 771 3908065; E-mail address:

Fig. S1. The relative quantum yield of GQDs.

Fig. S2. The stability of GQDs.

Fig. S3. Influence of pH value of phosphate buffer on the fluorescence property of GQDs.

Fig. S4. Influence of NaCl concentration on the fluorescence property of GQDs.

Fig. S5. Influence of pH value of phosphate buffer on the absorption property of AuNPs.

Fig. S6. Influence of GQDs concentration on the fluorescence of GQDs-AuNPs. AuNPs: 0.62 nM; 10 mM phosphate buffer: 7.0.

Fig. S7. Influence of pH value of phosphate buffer on the fluorescence of GQDs-AuNPs. GQDs: 0.47 mg mL−1; GNPs: 0.62 nM.

Fig. S8. Influence of reaction time on the fluorescence property of GQDs-AuNPs. GQDs: 0.47 mg mL−1; GNPs: 0.62 nM; 10 mM phosphate buffer: 7.0.

Fig. S9. Influence of L-cysteine concentration on the fluorescence property of GQDs. GQDs: 0.47 mg mL−1; 10 mM phosphate buffer: 6.0.

Fig. S10. Influence of AuNPs concentration on the fluorescence of GQDs-AuNPs-L-cysteine. GQDs: 0.47 mg mL−1; L-cysteine: 300 nM; 10 mM phosphate buffer: 6.0.

Fig. S11. Influence of pH value of phosphate buffer on the fluorescence of GQDs-AuNPs-L-cysteine. GQDs: 0.47 mg mL−1; AuNPs: 1.69 nM; L-cysteine: 300 nM.

Fig. S12. Influence of different addition sequences on the fluorescence property of GQDs-AuNPs-L-cysteine. GQDs: 0.47 mg mL−1; AuNPs: 1.69 nM; L-cysteine: 300 nM; 10 mM phosphate buffer: 6.0.

Fig. S13. Influence of reaction time on the fluorescence property of GQDs-AuNPs-L-cysteine. GQDs: 0.47 mg mL−1; AuNPs: 1.69 nM; L-cysteine: 300 nM; 10 mM phosphate buffer: 6.0.

Fig. S14. Influence of potentially interfering substances on the fluorescence property of GQDs.

1: Control; 2: 80 μM Guanine; 3: 60 μM Cytosine; 4: 50 μM Adenine; 5: 80 μM Thymine; 6: 90 μM Glucose; 7: 90 μM Galactose; 8: 80 μM Maltose; 9: 100 μM Fructose; 10: 50 μM Dopamine; 11: 50 μM Ascorbic acid; 12: 30 μM Reduced glutathione; 13: 20 μM Human serum albumin; 14: 30 μM Trypsin; 15: 40 μM Lysozyme; 16: 40 μM L-Methionine; 17: 30 μM Myglobin; 18: 30 μM N-Acetyl-L-cysteine; 19: 30 μM Homocysteine; 20: 30 μM Hemoglobin.