Highly sensitive detection of sulfasalazine based on the fluorescence quenching of a terbium complex probe

In the current study, a method for the determination of sulfasalazine (SSZ) based on the fluorescence quenching of Tb-2,6-pyridinedicarboxylic acid (Tb-DPA) complex probe in the presence of sodium dodecylbenzene sulfonate (SDBS) was established. Moreover, the mechanism of fluorescence quenching was studied and it was concluded that the process is static quenching and involved the formation of the SSZ-Tb-DPA ternary complex. Under the optimum conditions, the linear range of the method was 8.0 x 10(-8)-1.00 x 10(-6) M and 1.00 x 10(-6)-1.00 x 10(-4) M with the detection limit of 60 nM. The approach was successfully applied for the detection of SSZ in pharmaceutical preparations, urine, and human serum samples with recoveries between 98% and 106%.