Absorbance spectrum & λmax
Record absorbance or transmittance across the UV and visible range.
Useful forDyes, complexes, nanoparticle dispersionsSpectroscopy
UV–Vis Spectrophotometry
Absorbance spectroscopy in the ultraviolet and visible range
UV–Vis spectrophotometry measures how much ultraviolet and visible light a sample absorbs at each wavelength. It is used for concentration, optical band gap and colour studies of solutions, powders and films.
4 test optionsRange typically ~200–800 nmLiquids, powders and filmsTypical turnaround 3–5 working days
UV–Vis Spectrophotometry measurement principleIllustrative
01 / Overview
What is UV–Vis Spectrophotometry?
A monochromator selects one wavelength at a time from a broadband lamp and sends it through the sample. The detector compares the transmitted light with a reference, and absorbance is plotted against wavelength across the UV and visible range.
Absorbance follows the Beer–Lambert law, so solutions can be quantified against standards. For powders and opaque films, diffuse reflectance with an integrating sphere gives spectra suitable for estimating optical band gaps.
02 / How it works
How it works
- 01
Light is dispersed
A lamp's broadband light is split into its wavelengths by a monochromator.
- 02
One wavelength is selected
A slit passes a narrow band of wavelengths, and the band is scanned across the range.
- 03
Light passes the sample
The beam crosses the cuvette, and the sample absorbs part of it at each wavelength.
- 04
Absorbance is plotted
The detector signal is compared with a blank and converted to absorbance against wavelength.
03 / What it measures
What it measures
Concentration (Beer–Lambert)
Quantify an analyte in solution against a calibration curve.
Useful forAssays, solutions, quality controlOptical band gap
Estimate the band gap from the absorption edge using a Tauc plot.
Useful forSemiconductors, photocatalysts, filmsTransmittance of films
Measure how much light a coating or film lets through.
Useful forCoatings, glass, transparent electrodesDiffuse reflectance
Record the reflectance of powders and opaque solids.
Useful forPigments, powders, opaque films04 / Test options
Choose the UV–Vis Spectrophotometry options you need
4 options · none added yet
05 / Sample requirements
Sample requirements
- Accepted forms
- Solutions, dispersions, powders, pellets, films on glass or quartz
- Liquids
- Around 3–5 mL, plus 5–10 mL of the pure solvent for the blank
- Powders
- Around 0.2–0.5 g for diffuse reflectance
- Films
- About 10 × 10 to 25 × 25 mm; transparent substrate for transmittance
- Concentration
- Absorbance ideally below ~2; dilute strongly coloured solutions
- Send the pure solvent separately for the blank
- Keep liquids clear, free of bubbles and settled particles
- For films, include a bare substrate as reference if available
- No volatile or corrosive solvents without discussing first
- No hydrofluoric acid or solutions that etch quartz
Hazardous or air-sensitive samples: mention it in your request, and attach the MSDS if you have one.
06 / Results & turnaround
Results & turnaround
What you receive
- UV–Vis spectrum (absorbance, transmittance or reflectance)
- λmax / peak wavelengths
- Band gap from a Tauc plot on request
- Raw data files
- Report PDF
Turnaround & pricing
Typically 3–5 working days after samples reach the lab.
Price confirmed in your quotation, depending on user type, options and number of samples.
07 / Limitations
When UV–Vis Spectrophotometry isn't the right fit
Chemical bond or functional group identification
Trace metals or elemental content
Emission properties of luminescent samples
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