A facile and eco-friendly fluorometric method for the determination of methotrexate and folic acid in biological samples based on hollow luminescent carbon dots and chemometrics method.

A rapid, simple, and inexpensive spectrofluorimetric sensor has been developed for the simultaneous determination of methotrexate (MTX) and folic acid (FA) based on their interactions with hollow carbon dots (HCDs). Since the use of folic acid to cope with the toxic side effects of MTX in patients is essential, the simultaneous determination of these two compounds has been interesting. The results showed that  MTX could quench the fluorescence of HCDs with a dynamic quenching mechanism. The sensor exhibited a linear concentration range of 1.0 × 10 -6 -1.9 × 10 -4  mol L -1  for MTX and 1.5 × 10 -5 -9.4 × 10 -4  mol L -1  for FA and the obtained detection limits for MTX and FA were 1.6 × 10 -7  and 5.0 × 10 -7  mol L -1 , respectively. The applicability of the method was investigated in the analysis of the urine samples and the partial least squares (PLS) method was used for the simultaneous determination of MTX and FA.