Question

1. Consider a simple spectrophotometer with a diode array detector to collect a simultaneous visible light spectrum versus a more expensive double beam spectrophotometer that is capable of measuring in the ultraviolet and visible spectrum, in which a diode array detector is extremely rare. There are 2 major reasons why, based on the components of an instrument. What are they? Explain your reasoning.

Basically, it's asking why diode array detectors are rare in a double beam instrument. One reason should be about how the measurement is made and the other about the components of the detector.

Answer 1

Introduction:-

A diode array detector is made by the combination of an array of photo-diode and these types of detectors can detect the absorption of compounds in UV to Visible wavelength. These types of detectors are capable to extract information in terms of absorbance from a wide range of wavelengths at the same time.

Diode array detector based UV-VIS spectrometers is more fast, high resolution, and efficient as compared to convectional UV-VIS spectrometer. This type of spectrometer one can use two types of lamps used one for UV light (deuterium lamp) and another for visible light (tungsten/halogen lamp) simultaneously.

The diode array-based spectrometer is mostly a single beam spectrometer. If we use this type of detector in a double-beam spectrometer we have to modify the setup of the instrument in such a way that no wavelength reflected or absorbed (by the splitter) during the splitting of single beam two double beams. There is always a possibility of being absorbed or reflected a fraction of light with a certain wavelength from a wide range of wavelengths beam. If such a process is happening than we can lose the information corresponding to absorb or reflected wavelength in the splitting process. Maybe in the future, we can build a better splitter or alternate setup to make double beam diode arrays based spectrometer.