Determination of L-arginine content in Radix isatidis by a composite fluorescent probe of Pd (II)

In the presence of Britton-Robinson buffer solution (pH = 9.5) and surfactant of Tween-80, fluorescence intensity of calcein was quenched by Pd2+. However, the fluorescence intensity can be enhanced after adding a certain concentration of L-arginine, and the rate of the enhancement showed a good liner relationship with the added amount of L-arginine. We then established a fluorescence spectrometry for the determination of L-arginine. In addition, the linear range, along with detection limit, was different when the slit width changed. Thus, we could use a different slit width to meet our requirements according to the samples we treated. By testing actual samples and the reliability of our method, we found that our method was reliable for determining the content of L-arginine in Radix isatidis.