Spectrophotometry is a key technique in the analytical chemist’s arsenal, enabling quantitative measurements of the characteristic absorbance properties of different molecules. A measurement signal, typically in the ultraviolet-visible (UV-Vis) or infrared (IR) spectra, is used to probe sample materials and uncover various phenomenological optical properties. Spectrophotometers can uncover a wide range of key properties, including absorption, emission, fluorescence, spectral reflectance, and transmittance. Chief among these are absorbance and fluorescence.

How to Get the Best out of Combined Photometry/Fluorometry

Leading-edge spectrophotometers empower biochemists and life scientists to conduct absorbance and fluorescence measurements in a single instrument. Typically, users would have to choose between the likes of microvolume absorbance methods and fluorometry, as these two operating modes were mutually exclusive in conventional spectrophotometers.

DS-11 Series Spectrophotometers from DeNovix introduce a pioneering concept of combined absorbance/fluorescence measurements in a single instrument. With a proprietary sample retention technology and full cuvette compatibility, it can be used for microvolume absorbance analysis and larger volume analytical runs alike. The device is also equipped with a four user-selectable excitations sources for fluorescence mode and is compatible with PCR tubes and wide range of assay types. This ground-breaking setup paves the way for users to acquire powerful results from an array of sample types.

In order to get the most out of your DS-11 Spectrophotometer, it is important to follow a set of fundamental best practices.

Clean Sample Surfaces

Samples on DS-11 Series Spectrophotometers are held between an optical sapphire surface and the tip of a fiber optic cable in the arm. During measurement, the microvolume sample is compressed to the ideal path length. The surfaces can be quickly and easily wiped down before and after experiments using a dry laboratory wipe. To clean dried on samples, use distilled water (dH2O) or a mild HCl solution rather than detergents.

Pipette Samples Carefully

When performing a microvolume analysis, simply pipette samples directly onto the lower sample surface and close the arm. Avoid over-dosing of sample materials and take precautions to avoid cross-contamination. Use a fresh aliquot for each measurement, a fresh tip for each sample aliquot, and avoid introducing bubbles when loading samples. After measurements, remove the sample from both the top and bottom optical surfaces immediately with a dry wipe.

Container and Reagent Compatibility

DS-11 Series Spectrophotometers are compatible with an extremely wide range of assays, buffers, and other reagents. If you are uncertain of the instrument’s compatibility with a particular compound, run a blank measurement using dH2O with the test buffer and assess its absorbance properties. Materials with a strong absorbance at wavelengths of interest, such as RIPA buffers, are not ideal. Contact a member of the DeNovix team if you are uncertain about your spectrophotometer’s compatibility with a specific reagent.

For large volume absorbance measurements, the DS-11 Series supports cuvettes with standard dimensions of 12.5 mm W x 12.5 mm L x 45 mm H. It is important to use clean cuvettes for every analytical run. For DNA and protein quantitation, ensure UV-transparent sample holders are used to guarantee measurement accuracy.

For any questions that have not been answered in this article, simply get in touch with a member of the DeNovix team. We will happily answer all your questions about our class-leading microvolume spectrophotometer range.