uv vis l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
UV-vis PowerPoint Presentation
Download Presentation
UV-vis

Loading in 2 Seconds...

play fullscreen
1 / 13
ban

UV-vis - PowerPoint PPT Presentation

142 Views
Download Presentation
UV-vis
An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. UV-vis

  2. Applications • Quantitative analysis • Organics (if composition is simple and known) • Specific binding to chromaphore • Metal-ligand absorption (d-orbital splitting), (Co2+ experiment in gen chm)

  3. cuvette slit source detector Beer’s Law • A = -logT = log(P0/P) = ebc • T = Psolution/Psolvent = P/P0 • Works for monochromatic light • Compound x has a unique e at different wavelengths

  4. Beer’s Law Analysis • Choice of wavelength • Typically choose wavelength of maximum absorbance • May deviate from this to avoid an interference

  5. Common UV-vis instuments Scanning Instrument monochromator slit Tungsten Filament (vis) Photomultiplier tube slit cuvette Deuterium lamp Filament (UV)

  6. sources • Tungten lamp (350-2500 nm) • Deuterium (200-400 nm) • Xenon Arc lamps (200-1000 nm)

  7. Monochromator • Braggs law, nl = d(sin i + sin r) • Angular dispersion, dr/dl = n / d(cos r) • Resolution, R = l/Dl = nN, resolution is extended by concave mirrors to refocus the divergent beam at the exit slit

  8. Sample holder • Visible; can be plastic or glass • UV; you must use quartz

  9. Single beam vs. double beam • Source flicker

  10. Diode array Instrument mirror Diode array detector 328 individual detectors Tungsten Filament (vis) slit slit cuvette Deuterium lamp Filament (UV) monochromator

  11. Advantages/disadvantages • Scanning instrument • High spectral resolution (63000), l/Dl • Long data acquisition time (several minutes) • Low throughput • Diode array • Fast acquisition time (a couple of seconds), compatible with on-line separations • High throughput (no slits) • Low resolution (2 nm)

  12. HPLC-UV HPLC Pump HPLC column 6-port valve Mobile phase Sample loop UV detector syringe Solvent waste