Photodiode array detector. The PDA detector is often preferred in HPLC for its versatility and ability to gather more information about the sample compared to single-wavelength detectors (UV Detector). Learn about the basic concepts, materials, and modes of photodiode detectors, and how they operate on the internal photoelectric effect. A photodiode array (PDA) is a linear array of discrete photodiodes, based on photovoltaic principle, on an integrated circuit (IC) chip. The TC-Optics function . Photodiode Arrays (and why they aren't used for emission spectroscopy) A typical photodiode array has between 128 and 1024 diodes 25 µm wide, 500 - 2500 µm high. The photo diode array (PDA), also known as the diode array detector (DAD) can measure the entire wavelength range in real time, which may provide other advantages. The optional high-sensitivity cell has an 85 mm optical path length and is able to detect trace components that were conventionally difficult to detect. Principle of PDA Detector: The principle of a PDA (Photodiode Array) detector in HPLC is based on the absorption of light by analytes in a sample. A DAD can measure the absorption spectrum of components in the UV to VIS region at one time, which helps identification and quantification. The light creates electron-hole pairs and the electrons migrate to the nearest PIN or PN junction as shown in Figure 4910. gwzz yqg lbalj volc7 1b wt ym6ax ijtoou vf nus