The invention provides red fluorescent
carbon quantum dots used for detecting pH in cells and a preparation method and application thereof. The preparation method comprises the following steps: (1) weighing 0.1-0.2mmol of p-phenylenediamine solution and dissolving in 0.075-0.15mol of
ethylenediamine, to obtain faint yellow liquid; (2) arranging the solution to a
microwave oven, reacting for 5-25min with the power of 20-100%, cooling to
room temperature after reaction is ended, and adding 5mol / L of HCL until gas escapes; and (3) putting the obtained solution into a
dialysis bag of 500-1000Da, then putting the
dialysis bag into a containing with water for
dialysis for two days, to obtain a pure carbon
quantum dot water solution, and performing
freeze drying on the obtained pure carbon
quantum dot water solution to obtain light pink flocculent
carbon quantum dots. The
carbon quantum dots prepared according to the invention have the characteristics of long launching, high
quantum yield, good
biocompatibility and the like; and the carbon quantum dots have sensitive response to pH and can penetrate a
nuclear membrane to enter a
cell nucleus, so as to enter the
whole cell, thus achievingan effect of detecting the pH of the
whole cell.