Teaching Labs has six Thermo Genesis 180 spectrophotometers. These are dual beam spectrometers and are mainly used for recording scanning spectra of solutions although they can also perform kinetic and photometric measurements.

Scanning Mode

Recording scanning spectra of solutions is the main role of the Thermo Genesis 180 spectrophotometers. These are dual-beam instruments enabling any fluctuations in the light source during scanning to be cancelled out. Often a scanning spectrum will be recorded in order to determine the wavelength of maximum absorbance (λmax) which can then be used for photometric or kinetic measurements. Scanning spectra are also used to provide characterisation data for a compound.

Photometric Mode

Photometric mode is used to record absorbance values at a given wavelength. As absorbance is related to concentration through the Beer-Lambert law (A =  ε c l), the concentration of a solution can be determined through the use of standards and recording a set of measurements in photometric mode.

Kinetics Mode

Kinetic mode is used to record the absorbance at a given wavelength as a function of time. This allows the study of reaction rates for reactions which have starting material(s) or product(s) having an absorbance within the range of the spectrophotometer.