Bio- UV-Visible Spectrophotometer

Contact person: Marcos May
Location: Tan Hall 374 (Iglesia Lab)

The Cary 400 is a high performance UV-Vis reference spectrophotometer donated by Varian Corp. It has a working range larger than six absorbance units enabling accurate measurements of highly absorbing samples all the way to the low UV range. This system is designed for measurements of solid samples that can be held as powders within an in situ cell and not for routine atmospheric sampling of liquid or solid samples.

The spectrophotometer system includes:

  • 'Floating' solid aluminum casting - isolates the optics from external disturbances
  • Sealed nitrogen purging of the entire optical path - improves performance in the low UV where atmospheric water absorbs. The monochromator and sample compartments have separate purging plumbing
  • A large sample compartment with a removable floor plate - gives maximum flexibility when mounting samples
  • Out-of-plane design of the double Littrow monochromator - reduces photometric noise and stray light, and produces excellent resolution

The Non-Measurement-Phase-Stepping (NMPS) wavelength drive system of the Cary 400 spectrophotometer ensures that the measured photometric value at a particular wavelength will remain the same, regardless of scan speed. This ensures fast, accurate measurements.

The system also currently has a Praying Mantis Diffuse Reflection accessory (DRP-XXX) and a reaction chamber for the praying mantis diffuse reflection attachment (HVC-DR2 and HVC-DR3). This system allows in situ experiments at temperatures up to 600 oC with gas flow through a packed of sample contained within a shallow cylindrical sample holder.

The donation of this equipment by Varian is kindly acknowledged.


Diffuse reflectance measurements transformed into pseudo-absorbance spectrum using Kubelka-Munk function

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