UV Cut-Off Filter of a Photodiode Array Detector Improves the Quantitativity of L-Ascorbic Acid Through Its Photoprotection

A photodiode array detector (PDA) is frequently utilized as a detector in high-performance liquid chromatography (HPLC) system for a detection of various compounds. A PDA emits a light of a wide range wavelength including ultraviolet light (UV) which has a possibility to induce photodegradation of analyzed compounds. If so, target compounds might be degraded when analyzed in this HPLC system. Therefore, photoprotection during HPLC analysis is required for the accurate analysis. In this study, the protective effect of a UV cut-off filter, which can cut off UV especially at shorter wavelength (< 240 nm), on the quantitativity of a photodegradable compound L-ascorbic acid (AA) was examined. A UV cut-off filter prevents AA from photodegradation, followed by the improvement of several parameters of a calibration curve. Furthermore, this protective potency was significant in the case that photodegradability of AA was enhanced with the conditions such as a small injection volume and a low flow rate. This study strongly suggests that the UV cut-off filter is a useful equipment when analyzing photodegradable compounds.