Ultraviolet-visible (UV-Vis) spectrophotometry is a technique used to measure light absorbance across the ultraviolet and visible ranges of the electromagnetic spectrum. When incident light strikes matter it can either be absorbed, reflected, or transmitted. The absorbance of radiation in the UV-Vis range causes atomic excitation, which refers to the transition of molecules from a low-energy ground state to an excited state.

Before an atom can change excitation states, it must absorb sufficient levels of radiation for electrons to move into higher molecular orbits. Shorter bandgaps typically correlate to absorption of shorter wavelengths of light. The energy required for molecules to undergo these transitions, therefore, are electrochemically-specific. A UV-Vis spectrophotometer can use this principle to quantify the analytes in a sample based on their absorption characteristics.

Outlining UV-Vis Spectrophotometers

A UV-Vis spectrophotometer measures the intensity of light transmitted through a sample compared to a reference measurement of the incident light source. The renowned DS-11 series of UV-Vis spectrophotometers from DeNovix uses a pulsed Xenon flash lamp to interrogate microvolume samples with light across a wavelength range of 190 – 840nm. The transmitted light is acquired by a CCD optical detector with a wavelength accuracy of within 0.5nm.

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According to Beer-Lambert Law, the amount of light absorbed is directly proportional to the concentration of the sample and the distance the light travels through the sample; the pathlength.

UV-Vis spectrophotometers are therefore able to determine the concentration of specific analytes in a microvolume by controlling the analysis wavelengths and the pathlength. The DS-11 is equipped with proprietary SmartPath®Technology, which supports reliable measurements of samples at higher concentrations than any other UV-Vis spectrophotometer currently available. This uses real-time absorbance to assess the optimal path length per sample and make automatic adjustments to suit the equipment’s detection range.

The DS-11 series supports microvolume measurements for samples as small as 0.5 microliters (µL) as well as quartz or plastic cuvettes. Proteins, single- and double-stranded DNA (ssDNA and dsDNA), and ribonucleic acid (RNA) can subsequently be rapidly and automatically assessed for concentration, full spectral output, and sample purity.

UV-Vis Spectrophotometers from DeNovix

DeNovix supplies several models of the DS-11 series UV-Vis spectrophotometer for unmatched precision and the broadest-possible dynamic range. Models include microvolume and cuvette absorbance and fluorescence measurement modes.

If you would like to learn more about the technologies that we offer, read our previous post The Working Principle of a Fluorometer. Or, if you have any questions about our DS-11 UV-Vis spectrophotometer, simply contact us directly.