Ultraviolet-Visible(UV-Vis) spectroscopy is a technique used to quantify the light that is absorbed and scattered by a sample (a quantity known as the extinction, which is defined as the sum of absorbed and scattered light). In its simplest form, a sample is placed between a light source and a photodetector, and the intensity of a beam of light is measured before and after passing through the sample. These measurements are compared at each wavelength to quantify the sample’s wavelength dependent extinction spectrum. The data is typically plotted absorbance as a function of wavelength. Each spectrum is background corrected using a “blank” (a cuvette filled with only the dispersing medium) to guarantee that spectral features from the solvent are not included in the sample spectrum.
Our UV-Vis analysis is performed with Thermo Scientific GENESYS 10S Series UV-Vis spectrophotometer loaded with a high-intensity xenon lamp and dual-beam optical geometry. It can collect spectra from 190-1100 nm. The xenon lamp provides strong illumination across the ultraviolet, visible, and near- infrared electromagnetic spectrum. It is recommended to have at least 1 mL of solution without any particles to collect the spectrum. The solution will be loaded to either quartz or plastic cell with a path length of 1 cm. The measurements of the samples as well as the solvent that is used to prepare the sample will be measured with same instrumental configuration. The instrument has the following capabilities:
- Scan speeds up to 3,600nm/minute
- Have dual-beam optics for superior photometric accuracy
- Capable to acquire data from the UV to the near-IR
- Increase sample throughput with the integrated 6-cell changer
- Thermostating options with both circulating water and Peltier cooling (At the moment we don’t have the necessary accessories)
- Measure unusual or challenging samples with a variety of optional holders for test-tubes, long path cuvettes and filters
Specifications and Settings Use for the Measurements
| Optical Design | Dual Beam |
| Spectral bandwidth | 1.8 nm |
| Light source | Xenon flash lamp |
| Detector | Dual Silicon photodetector |
| Wavelength range | 190 – 1100 nm (depends on your selection) |
| Scan speed | Up to 3600 nm/min (depends on your selection) |
| Data interval for scanning | 0.1, 0.2, 0.5, 1.0, 2.0, 5.0 nm |
| Path length | 1 cm |
* for any other specification please contact instrumental assistant
Sample Preparation Guide
Following guide is for the preparation of general samples. It may possible to tailor your sample preparation according to your research needs. It is recommended to have at least 1 mL of sample for measurement in a standard quartz cuvette. In addition, we suggest having at least 5 to 10 mL of the solvent used to disperse your material, to be used to measure the solvent background and for any necessary dilution of your sample. If you have a solid sample it is recommended to prepare a dilute solution in a suitable solvent.
Click following link for the reservation of the UV-Vis instrument
Lecturer-In-Charge
Dr. Anushka Rajapaksha