Hydrogen peroxide assisted synthesis of sulfur quantum dots for the detection of chromium (VI) and ascorbic acid

Sulfur quantum dots (SQDs), heavy-metal-free quantum dots, are regarded as the next generation promising green nanomaterials compared with traditional heavy-metal-based quantum dots. However, there have been few reports on the synthesis and application of SQDs for analytical detection. Herein, an H2O2-assisted top-down method is used to synthesize SQDs. The as-obtained SQDs have good water dispersion, stability, photoluminescence (PL) properties and achieving a quantum yield (QY) to 11%. After adding Cr (VI) in SQDs, the fluorescence intensity decreases base on inner filter effect (IFE). Moreover, Cr (VI) can be reduced to Cr (III) when ascorbic acid (AA) is introduced into the SQDs - Cr (VI) system, accompanying the recovery of the fluorescence intensity. The fluorescence sensor displays high sensitivity and quickly response toward Cr (VI) and AA in a range of 10-120 mu mol L-1 and 20-500 mu mol L-1 with a detection limit of 0.36 mu mol L-1 and 1.21 mu mol L-1, respectively. In addition, the fluorescence sensor has been applied for the determination of Cr (VI) and AA in real samples. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Sulfur quantum dots (SQDs) were synthesized using an H2O2-assisted method, showing good performance in analytical detection, making them promising for future applications.