A UV spectrophotometer measures the absorption of ultraviolet (UV) light by a sample to determine its concentration or purity.

• UV spectrophotometers use a UV light source to emit a specific wavelength ...read more

Two points are going to cover here 1. Principle of UV-Visible Spectrophotometer and 2. How to use UV-Visible Spectrophotometer in pharmaceutical.

1. Principle of UV-Visible Spectrophotometer:

   "When a beam of monochromatic light is passing through a homogeneous absorbing medium the rate of decrease in intensity of light is directly proportional to the concentration and path length of the absorbing medium."

2. How to Use UV-Visible Spectrophotometer?

   The blank absorbs at only one wavelength, or at a particular range of wavelengths, but not more, and that absorbance is subtracted from the sample's absorbance.

   Once the blank is discarded and the cuvette has been rinsed twice with the sample, fill the cuvette about 75% full with the sample. Wipe the cuvette again afterward to ensure that it has not been touched by fingerprints.

   Make sure the cuvette is correctly oriented in the spectrophotometer, and secure the lid.

   Subtract the blank spectrum or measurement from the absorbance measurement or spectrum in the same wavelength range as the blank if the instrument does not do so automatically.

   Determine the absorbance maximum, or a maximum, from the collected absorbance spectrum.

For more visit this site