Quantitative UV Absorbance Spectra of Chemical Agents and Simulants

2008 ◽  
Author(s):  
J. M. Lochner ◽  
Aaron M. Hyre ◽  
Steven D. Christesen ◽  
Kristina R. Gonser
Keyword(s):  
Uv Absorbance ◽  
Chemical Agents ◽  
Absorbance Spectra

scholarly journals Optical Method for Cardiovascular Risk Marker Uric Acid Removal Assessment during Dialysis

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jana Holmar ◽  
Ivo Fridolin ◽  
Fredrik Uhlin ◽  
Kai Lauri ◽  
Merike Luman
Keyword(s):  
Uric Acid ◽  
Uv Absorbance ◽  
Chemical Laboratory ◽  
Dialysis Treatment ◽  
Mean Values ◽  
Double Beam ◽  
Multi Wavelength ◽  
Spent Dialysate ◽  
Treatment Procedures ◽  
Absorbance Spectra

The aim of this study was to estimate the concentration of uric acid (UA) optically by using the original and processed ultraviolet (UV) absorbance spectra of spent dialysate. Also, the effect of using several wavelengths (multi-wavelength algorithms) for estimation was examined. This paper gives an overview of seven studies carried out in Linköping, Sweden, and Tallinn, Estonia. A total of 60 patients were monitored over their 188 dialysis treatment procedures. Dialysate samples were taken and analysed by means of UA concentration in a chemical laboratory and with a double-beam spectrophotometer. The measured UV absorbance spectra were processed. Three models for the original and three for the first derivate of UV absorbance were created; concentrations of UA from the different methods were finally compared in terms of mean values and SD. The mean concentration (micromol/L) of UA was49.7±23.0measured in the chemical laboratory, and48.9±22.4calculated with the best estimate among all models. The concentrations were not significantly different (P≥0.17). It was found that using a multi-wavelength and processed signal approach leads to more accurate results, and therefore these approaches should be used in future.

Topochemical investigation on phenolic deposits in the vessels of afzelia (Afzelia spp.) and merbau (Intsia spp.) heartwood

Holzforschung ◽  
2006 ◽  
Vol 60 (6) ◽  
pp. 583-588 ◽  
Author(s):  
Gerald Koch ◽  
Hans-Georg Richter ◽  
Uwe Schmitt
Keyword(s):  
Chemical Composition ◽  
Uv Absorbance ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Vessel Walls ◽  
Distinct Maximum ◽  
Uv Microspectrophotometry ◽  
Absorbance Spectra

Abstract The topochemical distribution of phenolic deposits in the vessels of afzelia (Afzelia spp.) and merbau (Intsia spp.) heartwood was investigated by means of cellular UV microspectrophotometry (UMSP) to characterise the chemical composition and synthesis by pit membrane-associated enzymes. UV absorbance spectra of the deposits attached to the vessel walls of merbau are characterised by a distinct maximum at a wavelength of 368 nm representing the UV absorbance of pure robinetin (C15H10O7). Deposits in the vessels of afzelia display a typical spectrum of kaempferol (C15H10O2) with two distinct maxima at 270 and 350 nm. The pit membranes and pit canals of associated vessel and parenchyma cells are impregnated by these compounds. These results verify the assumption that the synthesis of deposits in afzelia and merbau is regulated by pit membrane-associated enzymes.

Understanding the behaviour of UV absorbance of natural waters upon chlorination using model compounds

2019 ◽  
Vol 5 (1) ◽  
pp. 172-184 ◽  
Author(s):  
Nicolas Beauchamp ◽  
Caetano Dorea ◽  
Christine Beaulieu ◽  
Christian Bouchard ◽  
Manuel Rodriguez
Keyword(s):  
Natural Waters ◽  
Uv Absorbance ◽  
Model Compounds ◽  
Chemical Structures ◽  
Uv Visible ◽  
By Products ◽  
Absorbance Spectra

This paper is the first to assess the chemical structures responsible for specific changes observed in the shape of the UV-visible absorbance spectra, and their relationship to disinfection by-products.

Predicting the UV Spectrum of Single Stranded DNA

2015 ◽  
Vol 804 ◽  
pp. 163-166
Author(s):  
Naphat Chathirat
Keyword(s):  
Experimental Result ◽  
Uv Absorbance ◽  
Uv Spectrum ◽  
Single Stranded Dna ◽  
Absorbance Spectra

A model was developed to predict the UV absorbance spectra and thus concentration of single stranded DNA (ssDNA) samples. The model was developed from UV absorbance spectra of ssDNA oligodeoxynucleotides determined at different concentrations. The model, which would predict the concentration of ssDNA from the A260 value, is shown to predict absorbance spectra of ssDNA as shown when compared to the experimental result.

scholarly journals Can Spectrophotometry Be Used to Quantify Zingiberene Sesquiterpenoids in Tomato Leaflet Extracts?

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1037
Author(s):  
Mohammad Dawood ◽  
John C. Snyder
Keyword(s):  
Interspecific Hybrid ◽  
Quantitative Estimate ◽  
Quantitative Method ◽  
Uv Light ◽  
Uv Absorbance ◽  
Double Bonds ◽  
Multiple Wavelengths ◽  
The Relationship ◽  
Absorbance Spectra

The presence of 7-epi zingiberene in wild tomatoes has been associated with arthropod resistance. Consequently, tomato breeders are attempting to introgress 7-epi zingiberene from wild to cultivated tomato requiring quantification of zingiberene. 7-Epi zingiberene likely absorbs UV light due to its conjugated double bonds and others have claimed that measurement of absorbance at 270 nm of tomato leaflet washes can be used to quantify zingiberene. However, this claim has never been critically evaluated. We initially evaluated this claim in an interspecific hybrid tomato generation that was segregating widely for zingiberene. Results indicated that the method does not obey the Beer–Lambert law. Consequently, we examined in detail aspects of the UV-absorbance of isolated zingiberenoids and leaflet washes obtained from parents and interspecific generations that were segregating for 7-epi zingiberene. Results indicated that isolated zingiberenoids, as well as leaflet washes containing zingiberenoids, have broad absorbance spectra with a λmax of 264 nm. For isolated zingiberenoids, the relationship between abundance and absorbance at 264 nm did obey the Beer–Lambert law. Average absorbance spectra for leaflet washes from interspecific generation plants showed subtle λmax shifts. Furthermore, the relationship between absorbance at 264 nm and zingiberenoid content of these generations did not obey the Beer–Lambert law. The use of multiple wavelengths for estimation of zingiberenoids in these breeding generations was explored and the inclusion of additional absorbances at one or two wavelengths always improved estimates. However, identified wavelength(s) differed among generations. Taken together, the results indicate that measurement of absorbance of tomato leaflet washes at a single wavelength is not a reliable quantitative estimate of zingiberenoids in leaflet washes. Estimates can be improved by utilizing absorbance at multiple wavelengths, but the particular wavelengths will vary among generations. Lastly, measurement of absorbance may be useful for identifying those relatively rare individuals in a generation that is widely segregating for zingiberenoid content. However, even in this situation, the determination of the actual 7-epi zingiberene content would need to be backstopped by a valid quantitative method.

scholarly journals Formation of exceptionally stable ketene during photo transformations of Bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

2019 ◽  
Author(s):  
Asitanga Ghosh
Keyword(s):  
Time Dependent ◽  
Uv Absorbance ◽  
Stability Studies ◽  
Absorbance Spectra ◽  
Bridgehead Position

Photoreaction of Bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores like 5,6 dibenzoyl moiety and phenyl or isopropenyl like electron withdrawing groups at the bridgehead position have been checked in different solvent and different wavelength. In all cases regioselective 1,5-photophenyl migration leading to vinyl ketenes from more congested site of the molecule to the less one have been observed. The ketenes were exceptionally stable both in air and in solution. Its stability studies in acetonitrile through time dependent UV absorbance spectra revealed that it remained almost unchanged at least for couple of weeks. 

Predicting the UV Spectrum of Oligodeoxynucleotide by 2D-Matlab

2017 ◽  
Vol 866 ◽  
pp. 37-40
Author(s):  
Naphat Albutt ◽  
Suejit Pechprasarn
Keyword(s):  
Initial Data ◽  
Extinction Coefficient ◽  
Uv Absorbance ◽  
Uv Spectrum ◽  
Absorbance Spectra

A 2D-Matlab model was developed to predict the UV absorbance spectra and thus concentration of oligodeoxynucleotide samples. This model will be valuable for researchers designing experiments involving oligodeoxynucleotides. Initial data was acquired from UV absorbance spectra of oligodeoxynucleotides 23, 24 and 34 bases long. The model, which would predict the concentration of DNA from the R260 value, is shown to predict absorbance spectra and the extinction coefficient of DNA as shown when compared across a range of concentrations.

A method to probe protein structure from UV absorbance spectra

2019 ◽  
Vol 587 ◽  
pp. 113450
Author(s):  
Amadeo B. Biter ◽  
Jeroen Pollet ◽  
Wen-Hsiang Chen ◽  
Ulrich Strych ◽  
Peter J. Hotez ◽  
...  
Keyword(s):  
Protein Structure ◽  
Uv Absorbance ◽  
Absorbance Spectra

Effect of Acetone and Kerosene on Skin Ultrastructure

1972 ◽  
Vol 30 ◽  
pp. 92-93
Author(s):  
A. P. Lupulescu ◽  
H. Pinkus ◽  
D. J. Birmingham
Keyword(s):  
Electron Microscopy ◽  
Human Skin ◽  
Osmium Tetroxide ◽  
Human Epidermis ◽  
Ultrastructural Changes ◽  
Chemical Agents ◽  
Skin Ultrastructure ◽  
Volar Surface

Our laboratory is engaged in the study of the effect of different chemical agents on human skin, using electron microscopy. Previous investigations revealed that topical use of a strong alkali (NaOH 1N) or acid (HCl 1N), induces ultrastructural changes in the upper layers of human epidermis. In the current experiments, acetone and kerosene, which are primarily lipid solvents, were topically used on the volar surface of the forearm of Caucasian and Negro volunteers. Skin specimens were bioptically removed after 90 min. exposure and 72. hours later, fixed in 3% buffered glutaraldehyde, postfixed in 1% phosphate osmium tetroxide, then flat embedded in Epon.

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