Determination of the Enantiomeric Composition of Guest Molecules by Chemometric Analysis of the UV−Visible Spectra of Cyclodextrin Guest−Host Complexes

2003 ◽  
Vol 125 (7) ◽  
pp. 1690-1691 ◽  
Author(s):  
Kenneth W. Busch ◽  
Isabel Maya Swamidoss ◽  
Sayo O. Fakayode ◽  
Marianna A. Busch
Keyword(s):  
Chemometric Analysis ◽  
Enantiomeric Composition ◽  
Guest Molecules ◽  
Visible Spectra ◽  
Uv Visible

Cellulose Nanofiber as Potential Absorbent Material for Chloride Ion

2021 ◽  
Vol 317 ◽  
pp. 263-269
Author(s):  
Muhammad Syukri Mohamad Misenan ◽  
Nurjahirah Janudin ◽  
Mas Amira Idayu ◽  
Mohd Nor Faiz Norrrahim ◽  
Siti Hasnawati Jamal ◽  
...  
Keyword(s):  
Low Cost ◽  
Cellulose Nanofibers ◽  
Chloride Ion ◽  
Absorption Capacity ◽  
Visible Spectra ◽  
Ft Ir ◽  
Uv Visible ◽  
Hcl Concentration ◽  
Hcl Solution

A simple, low cost and rapid analytical method for determination of HCl concentration after being treated with cellulose and cellulose nanofibers (CNF) is developed. This method is based on color intensity after the HCl solution is doped with sodium iodide (NaI). The color of HCl solution changes from colorless to yellow. The intensity of the color is measured by UV – Visible spectroscopy. The UV-Visible spectra of 0.15 M HCl treated with cellulose and cellulose nanofibers is reduced from its initial concentration. The CNF absorption capacity is higher as compared to cellulose. FT-IR analysis showed that there is interaction between C-H group from the CNF backboned and chloride ion from HCl solution.

Reaction Chamber and Cathode Configurations in Arc Production of Fullerenes

1994 ◽  
Vol 359 ◽  
Author(s):  
E. Pasqualini ◽  
C. Podesta ◽  
A. GarcÍa ◽  
A. Rafael ◽  
S. Dengra ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Reaction Chamber ◽  
Decomposition Rates ◽  
Deposit Formation ◽  
Cathodic Deposit ◽  
Visible Spectra ◽  
Uv Visible ◽  
Different Origins ◽  
Equivalent Conditions

ABSTRACTThe reaction chamber in the arc production of fullerenes was redesigned with a nozzle surrounding the decomposition zone to allow for clean collection of soot in a filtering cartridge. Quantitative analysis in the region of 300–430 nm in UV-visible spectra permits determination of the abundance of C60 and C70 in the soot. Calibrated curves of absorptivity for both pure fullerenes were employed. In equivalent conditions of current and pressure, electrographites of different origins have different decomposition rates and yields. A mechanism to interpret the cathodic deposit formation is proposed. Decomposition inside a closed cathodic cylinder yields 100% deposit.

scholarly journals Study of the β-Cyclodextrin Imipramine Hydrochloride Inclusion Complex and Determination of its Stability Constant (K) by UV-Visible Spectroscopy

2007 ◽  
Vol 4 (4) ◽  
pp. 550-558 ◽  
Author(s):  
Alamdar Ashnagar ◽  
Nahid Gharib Naseri ◽  
Bita Khanaki
Keyword(s):  
Stability Constant ◽  
Inclusion Complex ◽  
Visible Spectroscopy ◽  
Constant Amount ◽  
A Value ◽  
Visible Spectra ◽  
Imipramine Hydrochloride ◽  
Uv Visible ◽  
The Stability

In this research, the interactions of imipramine hydrochloride drug with β- cyclodextrin and the stability constant (K) of the inclusion complex formed between them were investigated by using UV-visible spectroscopy. Solutions consisting of a known and constant amount of imipramine hydrochloride and varying amounts of β- cyclodextrin were prepared in 0.1 M phosphate buffer (pH 7.4). The final solutions had cyclodextrin concentrations between 0.0011 and 0.0153 M. UV-visible spectra of each solution was taken at λmax= 250 nm. The absorbances at this wavelength were recorded and plotted against cyclodextrin concentrations. From the graph, the concentrations of free and bound imipramine hydrochloride and free β-cyclodextrin were calculated using the Beer-Lambert law. From these data, the stability constant was calculated and a value of K=52.26±11.41 mol-1L was obtained. The magnitude of the stability constant is discussed in terms of the relative sizes and the chemical natures of β-cyclodextrin and imipramine hydrochloride.

N-confusedmeso-tetraaryl-substituted free-base porphyrins: determination of protonation and deprotonation constants in nonaqueous media

2015 ◽  
Vol 19 (01-03) ◽  
pp. 251-260 ◽  
Author(s):  
Zhongping Ou ◽  
Xueyan Chen ◽  
Lina Ye ◽  
Songlin Xue ◽  
Yuanyuan Fang ◽  
...  
Keyword(s):  
Tautomeric Form ◽  
Equilibrium Constants ◽  
Single Step ◽  
Free Base ◽  
Nonaqueous Media ◽  
Tautomeric Forms ◽  
Visible Spectra ◽  
Phenyl Rings ◽  
Uv Visible

The protonation and deprotonation reactions for a series N-confused meso-tetraaryl-substituted free-base porphyrins containing electron-donating or electron-withdrawing substituents was monitored in CHCl3and DMF by UV-visible spectroscopy during titrations with trifluoroacetic acid or tetra-n-butylammonium hydroxide. The spectroscopic data was also used to calculate equilibrium constants for these reactions. The examined compounds are represented as (XPh)4NCPH2, where "NCP" represents the N-confused porphyrin π-conjugated macrocycle and X is a CH3O , CH3, H or Cl para-substituent on the four meso-phenyl rings (Ph) of the compound. The porphyrins can exist in two tautomeric forms depending upon the solvent and each tautomer undergoes two stepwise protonation reactions leading to formation of the mono- and bis-protonated porphyrins, [(XPh)4NCPH3]+and [(XPh)4NCPH4]2+. A single step deprotonation is observed for the same compounds in DMF and the product is assigned as [(XPh)4NCPH]-. Comparisons are made between UV-visible spectra of the protonated, neutral and deprotonated forms of the porphyrin and the effect of the porphyrin ring substituents and tautomeric form of the neutral porphyrin on the UV-visible spectra and protonation constants is discussed along with data from DFT calculations.

Infrared and UV-visible spectra of layer semiconductors Gas, GaSe and GaTe

1977 ◽  
Vol 38 (10) ◽  
pp. 1293-1299 ◽  
Author(s):  
U. Giorgianni ◽  
G. Mondio ◽  
P. Perillo ◽  
G. Saitta ◽  
G. Vermiglio
Keyword(s):  
Visible Spectra ◽  
Uv Visible
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