A novel nitrogen-doped carbon quantum dots as effective fluorescent probes for detecting dopamine

•A novel N-CQDs were prepared by facile solid-heat method using glycine and urea.•The N-CQDs possessed a relatively high fluorescence QY (21.04 %).•The N-CQDs exhibited very high sensitivity and selectivity to dopamine.•This sensor successfully used for dopamine detection in human serum and rat serum.