Liquid Chromatography-Diode Array Detection

Diode array detection is a multi-wavelength detection system that enables the simultaneous collection of absorption data from a range of UV and visible (UV/vis) wavelengths.
Scanning and processing of the signals enables ‘snapshots’ of the complete UV/vis absorption spectrum of the eluent flowing through the LC detector cell to be collected and stored over time.  Since many organic compounds have characteristic UV/vis absorption spectra due to the presence of chromophoric groups or structures, this feature can be utilised to assist in identifying the component as it passes through the detector.  By simultaneously monitoring a range of wavelengths the absorption spectrum of a compound can be produced and compared with standard spectra from reference compounds.  In addition, by selecting the wavelength of maximum absorption improved detection sensitivity can be achieved.
It is also possible to use the DAD to monitor several wavelengths of interest simultaneously or to correct for variations due to solvent changes caused during gradient elution.

SGS M-Scan has an Agilent 1200 DAD coupled to an Agilent 1100 HPLC system for LC-DAD and can also offer LC-DAD/MS by linking this system to its Sciex API150 mass spectrometer.

Applications for LC-DAD and LC-DAD/MS include the analysis of chromophores and dyes including those used in jet fuel and agricultural diesel.