Sensitive determination of rutin by spectrofluorimetry using carbon dots synthesized from a non-essential amino acid

The present study describes the synthesis of carbon dots (CDs) using a non-essential amino acid, asparagine as a precursor. The HR-TEM image shows that the size of the prepared CDs was 2.9 +/- 0.2 nm with a spherical morphology. The UV-visible spectrum of CDs exhibits a major band at 307 nm along with a shoulder band around 207 nm corresponding to n-pi* and pi-pi* transitions, respectively. Further, the CDs show emission maximum at 441 nm when excited at 348 nm. The synthesized CDs were then exploited for the determination of rutin by spectrofluorimetry based on the decrease in emission intensity at 441 nm. It was found that emission intensity of CDs at 441 nm was decreased while adding 0.5 mu M rutin to CDs. On the other hand, addition of other metal ions and anions including 5 mM Mg2+, K+, Ca2+, Na+, NO3- and oxalate, 2.5 mM Cu2+ and Fe3+ and 3 mM glycine, glucose, histidine, proline and cysteine does not affect the emission intensity at 441 nm. A good linearity was observed for the emission intensity against 0.5-15 mu M rutin with a correlation coefficient of 0.997 and the limit of detection was found to be 1 x 10(-7) M (61 mu g/L) (S/N = 3). The real sample analysis was done by determining rutin in a pharmaceutical sample. (C) 2018 Elsevier B.V. All rights reserved.