I tried with plastic and glass cuvette and I have the same fluctuations.
The sample is plant extract + DW.
Regards
i agree fully with the answer of Peter.
Please give the following infos:
- concerning the UV-Vis spectrometer: single, dual beam or diode arrays.
- How old is your spectrometer and the name of your spectrometer (e.g. Varian, Zeiss, Unicam, Edinburgh, HP, Hitachi.....)
- You write " Plastic" in your posted question! As scientist, you must give p.e. PS (polystyrol) or PMMA (polymethylmethacrylat).
The cut off for PS is : 340 nm-900 nm
" " " for PMMA is 300-900 nm
(Leaflet cuvettes from Brand Cy Germany)
Glass cuvettes 380- 780 nm
Fused quartz below 380 nm
Cuvettes must be cleaned prior to use .
Please note that your solvent for UV-Vis must be pure (spectranal quality) and has an own cut off.
You posted a spectrum without infos about :
-Solvent
-Purity of your extract (A mixture of plant extract is obscure and obsolete and give no infos about the structure.
Formerly , a good spectroscopist wrote the number of hours spent with the measure of spectra. After a certain number of hours (see you spectrometer booklet) , the after-sales service was coming . It was expensive but the " spectro" gave the best spectra in the next time.
JRG
I strongly agree with the replies of Peter Kapusta and Jean Rene Grezes.
Dear Jean Rene Grezes,
I wrote a general question as I have the same problem with different samples. The answers to your questions are below
concerning the UV-Vis spectrometer: dual beam
The name of your spectrometer : Perkin Elmer spectrum 100
- You write " Plastic" in your posted question! As scientist, you must give p.e. PS (polystyrol) or PMMA (polymethylmethacrylat).
The cut off for PS is : 340 nm-900 nm
" " " for PMMA is 300-900 nm =========== both tried
Glass cuvettes 380- 780 nm ========== tried
Cuvettes must be cleaned prior to use ========== done
No solvent === Only sample with DW.
Peter is right with his answer! No MISTAKE!
I join the link for the maual Perkin elmer spectrum 100 FT-IR . Please consult the page 23 a.s.o. ...
https://www.research.usf.edu/rf/docs/perkin-elmer-spectrum-100-ftir-users-guide.pdf
On other part , DW ( i hope you mean Dist. Water) is a solvent with own cut-off. . Here the UV absorbance cut-off of pure Dist. or bidist. water is 180 nm.
If you mean DW as DRY WATER (see article) I join an abstract, please write no ACRONYM in your posted question or give DW (dist. Water or Dry Water):
Dry water (DW) is a kind of Pickering emulsion, where air serves as the nonpolar continuous phase in place of common organic solvents. Dry gel (DG) has also been prepared, which is superior to DW as a promising material for recyclable gas storage or gas separation. Here we add a new member, dry ionic liquid (D-IL), to those two kinds of ‘‘dry matter’’. Because of the non-volatility, D-IL is free from the fatal defect of DW and DG, i.e., collapse due to the temporal water vaporization in an open system. The chemical inertness of D-IL also provides potential applications for green chemistry, e.g., an organic solvent-free micro reaction vessel. In this study we report the first successful preparation of D-IL and discuss the preparation conditions such as properties of IL, IL/silica composition and water content.
Source:
Communication “Dry ionic liquid” as a newcomer to “dry matter”
Kazushi Shiratoa and Mitsuru Satoh*a
Show Affiliations
Soft Matter, 2011,7, 7191-7193
DOI: 10.1039/C1SM05999H
Received 30 May 2011, Accepted 15 Jun 2011
First published online 06 Jul 2011
Another link:
Here a link for P. E. UV-Vis spectrometers
http://www.upc.edu/sct/documents_equipament/d_229_id-435.pdf
JRG
@ Jean Rene Grezes
Thank you for the file. I wrote the name correctly. DW is Distilled Water.
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