There are a number of spectrophotometer products currently available. Some are utilized along with various analytical instruments. Some fit on the bench yet others are used in several different industrial environments. Here we’ll examine two kinds of UV based products used in the laboratory area.
PDA, or Photodiode Array spectrophotometers, processes an array of photodiodes to investigate the light emitted from transmission of light by way of a liquid sample inside the spectrophotometer. This leads to smaller devices, right down to even handheld analyzers. This technique can be used in lots of UV spectrophotometer products today, and is an extremely precise instrument.
The application process can be explained as a simple light detecting device that features a myriad of detectors, each calibrated for any specific wavelength of visible or ultraviolet light. It can be comprised of about six parts: The light source, often a tungsten lamp coinciding with a deuterium diode for UV detecting, a collimator to direct the light beam which in turn moves by way of a slit calibrated for the instruments qualifications, the beam is reflected via a mirror to a grating comprised of calibrated prisms, which split the light into individual wavelengths. Then this light is transmitted to a multitude of specific photodiodes.
The light source lies in front of the sample, which produces a diluent or reagent mixed with the material being analyzed. This sample must be free from debris and turbidity since this could interfere with the analytical process. The light travels through the sample, causing absorption in the light through the sample, and the beam is sent to the grating, separating the light into its specific wavelengths. This in turn is reflected from your grating to a multi-channel detector comprised of the photodiodes hard wired to monitor specific wavelengths of light.
The Scanning UV visible spectrophotometer carries a different configuration. The light source is first reflected off a concentration mirror, then is split up into the wavelengths of light based on the prismatic grating. This divided light is sent to another focusing and concentration mirror. This light is then focused over the sample with a scanning mirror, plus the resulting absorption with the sample measured by the photoelectric detector.
Both of these instruments are capable of analyzing almost anything which can be dissolved in to a diluent or solvent. Calibration is performed by a blank diluent used in the instrument before analysis, thus giving the equipment a reference point for analyzing the samples. These kinds of spectrophotometers instruments are used globally for many different uses and disciplines.