LimsPulse
Spectroscopy

UV-Visible Spectrophotometer

Measures how much ultraviolet or visible light a solution absorbs at each wavelength. Used in pharma QC for identification, assay, dissolution and many quick quantitative tests.

  • Pharmaceutical
  • Biotech
  • Food & beverage
  • Environmental
  • Chemicals
  • Academic research
Photo of a UV-Visible Spectrophotometer
Photo: Wiki210397, CC BY-SA 4.0 (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check the instrument is within its calibration due date and the logbook has no open issues.
  2. 2Select matched quartz cuvettes for UV work and check they are clean, unscratched and free of fingerprints.
  3. 3Prepare the blank using the same solvent (and the same lot) as the sample and standard.
  • Handle cuvettes only by the frosted or ribbed sides; fingerprints on the optical faces absorb light.
STAGE 2

Start-up

  1. 1Switch on the instrument and let it complete its self-test (initialisation).
  2. 2Allow the lamps to warm up as the manufacturer recommends (commonly 15–30 minutes) so the baseline is stable.
  3. 3Set the wavelength, scan range, spectral bandwidth and measurement mode from the method.
  4. 4Run a baseline correction or auto-zero with the blank in both cell positions.
  • Do not open the lamp housing while the lamps are on; the deuterium lamp emits intense UV.
STAGE 3

Measuring samples

  1. 1Rinse the sample cuvette two or three times with the solution to be measured, then fill it to about three-quarters full.
  2. 2Wipe the outside with lint-free tissue and check for air bubbles.
  3. 3Place the cuvette in the holder with the same orientation each time and read the absorbance or record the spectrum.
  4. 4Check the blank again periodically during long runs to confirm the baseline has not drifted.
  5. 5Keep readings within the linear range of the method; dilute samples that read above it.
  • Absorbance readings above about 2 are unreliable because so little light reaches the detector; stray light makes them read low.
  • Volatile solvents can evaporate from an uncapped cuvette and change the concentration; cap the cell or measure promptly.
STAGE 4

Shutdown

  1. 1Rinse cuvettes with solvent and then water (or a suitable volatile solvent) and let them dry upside down or store them in their case.
  2. 2Clean any spills in the sample compartment.
  3. 3Switch off the lamps and the instrument as per the SOP, and complete the usage log.
In LimsPulse · Calibration Management

Keep every UV-Vis in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how