Multiple Wavelength Data Acquisition with the Vanquish Variable Wavelength Detector

In UV-Vis absorption measurement, the selection of the best detection wavelength has a substantial impact on the analytical result. What are the criteria for a suitable wavelength selection? The main requirement for the wavelength choice is a sufficient absorption by the various analytes in the sample, combined with acceptable light transmittance by the mobile phase. At detection wavelengths λ ≤ 220 nm, most compounds absorb (near-universal detection), which is one reason why this detection wavelength area is frequently used. Variable wavelength detectors (VWDs) are UV-Vis absorption detectors commonly used in routine analysis. For multiple wavelength acquisition, the monochromator in the detector optics must mechanically switch between the respective wavelengths. This technical note explains the background of the two approaches and discusses pros and cons on the basis of a separation of dyes.