Types of UV-Visible Spectrometers:

Having learnt the basics of the various components of UV-Visible spectrometers let us now see how these individual elements are arranged in a spectrometer. Widely speaking there are three kinds of spectrometers. Let us learn about their set ups.

Single Beam Spectrometers

As the name suggests, these instruments holds a single beam of light. The similar beam is used for reading the absorption of the sample as well as the reference. The schematic diagram of a classic single beam UV- Visible spectrometer is shown in Figure. The radiation from the source is passed by a filter or an appropriate monochromator to get a band or a monochromatic radiation. It is then passed by the sample (or the reference) and the transmitted radiation is detected through the photodetector. The signal so acquired is sent as a read out or is recorded.

Figure: Schematic diagram for a single beam UV-VIS spectrometer

Classically, two operations have to be performed - first, the cuvette is filled along with the reference solution and the absorbance reading at a provided wavelength or the spectrum over the desired range is recorded. Another, the cuvette is taken out and rinsed and filled with sample solution and the procedure is repeated. The spectrum of the sample is acquired through subtracting the spectrum of the reference from that of the sample solution.