scholarly journals A New Approach on the Amino Acid Lysine Quantification by UV-Visible Spectrophotometry

2020 ◽  
Vol 71 (8) ◽  
pp. 159-175
Author(s):  
Habib Bouzid ◽  
Cesar M. C. Filho ◽  
Joana Rita C. Marques ◽  
Artur J. M. Valente ◽  
Licinio M. Gando-Ferreira
Keyword(s):  
Aqueous Solution ◽  
Amino Acid ◽  
Volume Ratio ◽  
Absorbance Spectrum ◽  
Reaction Conditions ◽  
New Approach ◽  
Analytical Technique ◽  
Initial Ph ◽  
Uv Visible ◽  
Ph Range

The methodology of the amino acid lysine (Lys) analysis using ninhydrin (Nin) reagent by spectrophotometric method was in-depth studied and improved. The optimization of time, Lys to Nin volume ratio and temperature were explicitly investigated. A specific wavelength of 479 nm was set according to the peak of the absorbance spectrum. The reaction time between Lys and Nin, in aqueous solution, occurs during 50 min. The Lys/Nin ratio 1.67 appeared most effective for this reaction. Moreover, the absorbance increased with temperature until a stable value was achieved nearly at 85�C. It was also found that the reaction is more efficient at initial pH 6 corresponding to formation of high amount of coloured product. Furthermore, the pH of post-reaction mixture was around 4 for different concentrations of lysine and initial pH range 3�10. For lysine solution contaminated with potassium (a representative interfering species) and after variation of the reaction conditions, the maximum wavelength (479 nm) was not affected. Mastering the use of these parameters leads to a good usage of this analytical technique which is simple, fast, accurate, less expensive and especially less harmful towards the environment and human health.

An efficient and eco-friendly method for the thiol-Michael addition in aqueous solutions using amino acid ionic liquids (AAILs) as organocatalysts

2020 ◽  
Vol 92 (1) ◽  
pp. 97-106
Author(s):  
Roberto Figueroa Guíñez ◽  
José G. Santos ◽  
Ricardo A. Tapia ◽  
Jackson J. Alcazar ◽  
Margarita E. Aliaga ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ionic Liquids ◽  
Amino Acid ◽  
Efficient Method ◽  
Michael Addition ◽  
Rate Constants ◽  
Michael Reaction ◽  
High Rate ◽  
Reusable Catalyst ◽  
Reaction Conditions

AbstractA series of amino-acid based ionic liquids (Bmim[AA]s) have been synthesized and evaluated as catalysts, in aqueous solution. The results of a kinetic study of the thiol-Michael reaction of L-Cysteine with trans-β-nitrostyrene demonstrated the advantages of using (Bmim[AA]s) as organocatalysts. The benefits include high rate constants; mild reaction conditions; and, a reusable catalyst, which leads to a simple and efficient method for these important kinds of reactions.

Degradation of Ammonium butyl-dithiophosphate by Fe2+/NaClO Process

2013 ◽  
Vol 800 ◽  
pp. 601-605
Author(s):  
Xi Sheng He ◽  
Hui Qing Peng
Keyword(s):  
Aqueous Solution ◽  
Exponential Decay ◽  
Reaction Conditions ◽  
Initial Concentration ◽  
First Order ◽  
Initial Ph ◽  
Optimum Reaction

The initial pH, initial concentration of Fe2+and NaClO on the degradation of ammonium butyl-dithiophosphate using Fe2+/NaClO process have been investigated in this paper. The results shows that under the optimum reaction conditions of a temperature 28°C, pH 4.0, the initial concentration of Fe2+and NaClO is 15 mg/L and 5.33 mL/L, respectively, about 87.86% ammonium butyl-dithiophosphate removal can be achieved within 150 min by using a Fe2+/NaClO process. The degradation of ammonium butyl-dithiophosphate under different NaClO concentration conditions follows the first order exponential decay equations. The Fe2+/NaClO can efficiently oxidation of ammonium butyl-dithiophosphate in aqueous solution and can be an effective process for the treatment of ammonium butyl-dithiophosphate wastewater.

Degradation of Ciprofloxacin in Aqueous Solution by the Fenton Process

2012 ◽  
Vol 610-613 ◽  
pp. 352-355 ◽  
Author(s):  
Ji Feng Yang ◽  
Hong Hui Chen
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Oxidation Process ◽  
Ph Value ◽  
Fenton Process ◽  
Ferrous Ions ◽  
Reaction Conditions ◽  
Initial Ph ◽  
Optimum Reaction ◽  
Ciprofloxacin Removal

The present study provides results describing the degradation performance of ciprofloxacin antibiotic via Fenton treatment. The effect of reaction conditions including the initial pH value, and dosages of ferrous ions and hydrogen peroxide on ciprofloxacin and COD removal was investigated. Ciprofloxacin removal efficiency of more than 90% was achieved under optimum reaction conditions of pH value of 2, dosages of 0.75 mmol/L of ferrous ion, and 2.0 mmol/L of hydrogen peroxide after 10min. However, the change of COD in aqueous solution was not obvious and further study about intermediate products during oxidation process should be carried out in the future.

scholarly journals Di- and tetranuclear gadolinium (III) complexes of 2-hydroxypropane-1,2,3-tricarboxylic acid and 1,2,2-trimethylcyclopentane-1,3-dicarboxylic acid : identification and characterization

2017 ◽  
Vol 5 (2) ◽  
pp. 102
Author(s):  
Mohammed Riri ◽  
Farid Hadhoudi ◽  
Mustapha Hor ◽  
Samir Ezzemouri ◽  
Tarik Eljaddi ◽  
...  
Keyword(s):  
Citric Acid ◽  
Dicarboxylic Acid ◽  
Tricarboxylic Acid ◽  
Analytical Technique ◽  
Uv Visible ◽  
Ph Range ◽  
Camphoric Acid ◽  
Identification And Characterization ◽  
No Absorption

Our studying involved, Identification and characterization of two novel gadolinium complexes with 2-hydroxypropane-1,2,3-tricarboxylic acid (citric acid) noted H3L and 1,2,2-trimethylcyclopentane-1, 3-dicarboxylic acid (camphoric acid) noted H2L in aqueous solution and in pH range 5,5–7,5. These acids containing the donor atoms (oxygen of OH and COOH), the formatted complexes are colorless and have no absorption band UV–visible. So, to determine the composition and stabilities of these complexes in solution, we have used an analytical technique called «Indirect Photometry Detection (IPD) » have identified multi-nuclear and multi-dentate complexes studied in this work. Giving for these colorless complexes with a mole ratio (M:L): (4:2) for Gd (III)–Citric acid and (2:2) Gd (III)–Camphoric acid. In addition, we have shown that the compositions and stabilities constant of these complexes are depended on the acidity of the medium.

Electrochemical degradation of safranine T in aqueous solution by Ti/PbO2 electrodes

2020 ◽  
Vol 98 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Baichen Liu ◽  
Bingli Ren ◽  
Yun Xia ◽  
Yang Yang ◽  
Yingwu Yao
Keyword(s):  
Aqueous Solution ◽  
Current Density ◽  
Intermediate Structure ◽  
Electrochemical Degradation ◽  
Reaction Conditions ◽  
First Order Kinetics ◽  
Safranine T ◽  
Initial Ph ◽  
Degradation Reaction ◽  
Optimal Reaction

The electrochemical degradation of safranine T (ST) in aqueous solution was studied. The effects of current density, initial concentration of ST, initial pH values, and Na2SO4 concentration on electrocatalytic degradation of ST in the aqueous solution by Ti/PbO2 electrode were analyzed. The experimental results showed that the electrochemical oxidization reaction of ST fitted a pseudo first order kinetics model. By using the Ti/ PbO2 electrode as the anode, 99.96% of ST can be eliminated at 120 min. It means that the electrochemical degradation of ST in aqueous solution by the Ti/PbO2 electrode was very effective. The optimal reaction conditions were as follows: current density, 40 mA cm−2; initial ST concentration, 100 mg L−1; Na2SO4 concentration, 0.20 mol L−1; initial pH, 6. It can be known from the test of UV–vis and HPLC in the reaction process that the intermediates will be generated, and the possible intermediate structure was studied by HPLC–MS test. However, with the progress of degradation reaction, the intermediates will eventually be oxidized into CO2 and H2O. Cyclic voltammetry and fluorescence experiments proved that ST was indirectly oxidized through the generation of hydroxyl radicals. Under the optimal reaction conditions, the energy required to completely remove ST was 17.92 kWh/m3.

The Stability and Structure of Complex Species Formed in Equilibrium Reactions of Diethyltin(IV) with N-D-Gluconylamino Acids in Aqueous Solution

1995 ◽  
Vol 50 (4) ◽  
pp. 515-523 ◽  
Author(s):  
B. Gyurcsik ◽  
N. Buzás ◽  
T. Gajda ◽  
L. Nagy ◽  
E. Kuzmann ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Amino Acid ◽  
Water Soluble ◽  
Complex Formation Equilibria ◽  
Complex Species ◽  
Carboxylate Oxygen ◽  
Equilibrium Reactions ◽  
Formation Equilibria ◽  
The Stability ◽  
Ph Range

Complex formation equilibria of diethyltin(IV) with five N-D-gluconylamino acids in aqueous solution (I = 0.1 M, NaClO4) were studied and the stabilities of the species were determined by potentiometric titrations. Diethyltin(IV) complexes of α-amino acid derivatives are water-soluble in the physiological pH range, while in the presence of N-D-gluconyl-β-alanine a precipitate is formed, which dissolves with increasing pH. 13C NMR measurements showed that in the N-D-gluconyl-α-amino acid complexes the ligand is coordinated through its deprotonated carboxylate oxygen, amide nitrogen and C(2)-hydroxy group, while for the soluble N-D-gluconyl-β-alanine complex the ligand is coordinated via the deprotonated carboxylate and C(3)-, C(4)-, C(5)-hydroxy groups. Mössbauer measurements reflected the geometry of the complexes formed.

scholarly journals Efficient capture of phosphate from aqueous solution using acid activated akadama clay and mechanisms analysis

2018 ◽  
Vol 78 (7) ◽  
pp. 1603-1614 ◽  
Author(s):  
Ying Wang ◽  
Hui He ◽  
Nan Zhang ◽  
Kazuya Shimizu ◽  
Zhongfang Lei ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ph Effect ◽  
Phosphate Removal ◽  
Phosphate Adsorption ◽  
Order Kinetic ◽  
Negative Effects ◽  
Initial Ph ◽  
Intra Particle Diffusion ◽  
Langmuir Isotherm Model ◽  
Ph Range

Abstract In this study, akadama clay, a kind of volcano ash, was activated with sulfuric acid and then evaluated for the adsorption of phosphate from aqueous solution via batch experiments. The effects of adsorbent dose, initial pH and coexisting anions on phosphate removal by natural akadama clay and acid-activated akadama clay were investigated. Based on the pH effect, the modified adsorbent could efficiently capture phosphate over a wider pH range of 3.00–6.00 than natural akadama clay. Competitive anions showed negative effects on the phosphate adsorption, especially citrate and carbonate. The adsorption process followed the pseudo-second-order kinetic equation and the intra-particle diffusion. Langmuir isotherm model was found to fit the data better than Freundlich model, and the maximum adsorption capacities of phosphate onto the natural akadama clay and acid-activated akadama clay were 5.88 and 9.19 mg/g, respectively. Furthermore, thermodynamic studies confirmed that the adsorption of acid-activated akadama clay was a spontaneous process. The mechanisms of phosphate adsorption on the clay could be ascribed to electrostatic attraction and ligand exchange. These results suggest that after modification, acid-activated akadama clay could be used as a promising adsorbent for phosphate removal from wastewater in real application and then further used as fertilizers.

scholarly journals Response surface methodological approach for optimizing removal of ciprofloxacin from aqueous solution using thermally activated persulfate/aeration systems

2017 ◽  
Vol 19 (3) ◽  
pp. 389-395 ◽  
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Methodological Approach ◽  
Persulfate Oxidation ◽  
Thermally Activated ◽  
Initial Ph ◽  
Ph Range ◽  
Optimized Conditions ◽  
Mn3o4 Nanoparticles ◽  
Activated Persulfate

Being used in large quantities for some decades, antibiotics have been of little notice since their existence in the environment. Present study aims at investigating the optimization of Ciprofloxacin removal (CIP) in Thermally Activated Persulfate (TAP)/Aeration systems by Central Composite Design (CCD). The effect of operating parameters including initial pH, CIP concentration, Persulfate concentration and temperature on the removal process was investigated in order to find out the optimum conditions. Typically, high temperature, high Persulfate dose, and low initial CIP concentration increased the removal efficiency of CIP. At the tested pH range of 3–11, the highest removal occurred at pH 3.93. Finally, the effects of Mn3O4 Nanoparticles, N2 gas, and COD reduction in optimal condition were studied. Mn3O4 Nanoparticles and N2 gas in optimized conditions increased the removal efficiency from 93.41 to 90.1, respectively. The results showed that Thermally Activated Persulfate oxidation was the efficient process for the treatment of aqueous solution containing Ciprofloxacin due to the production of Sulfate radicals.

Removal of Methyl Red from Aqueous Solution by Adsorption onto Mg-Al HTLc

2013 ◽  
Vol 750-752 ◽  
pp. 1426-1429
Author(s):  
Yun Bo Zang
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Contact Time ◽  
Adsorption Process ◽  
Bulk Solution ◽  
Methyl Red ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Ph Range ◽  
Percent Removal

In this study, removal of Methyl Red from aqueous solutions by synthetic Mg-Al-HTlc was investigated as a function of contact time, pH and temperature. It is found that HTlc could reduced Methyl Red concentration effectively. The kinetic process which reached equilibrium at about 2h can be fitted by pseudo-second order kinetics. The percent removal of MR by the HTlc was dependent on the initial pH of bulk solution. There was no much changes in amount of adsorption in the initial pH range of 6-8, while it reached maxium at about of 9. The adsorption process was endothermic.

Preparation of Mg-Fe HTLCs and Study on the Adsorption Performance

2014 ◽  
Vol 675-677 ◽  
pp. 647-653
Author(s):  
Hong Bin Lv ◽  
Yao Li ◽  
Wan You Zhang ◽  
Li Juan Xi
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Order Kinetic ◽  
Sulfate Ions ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Ph Range ◽  
Synthesized Materials

Mg-Fe hydrotalcite-like compounds (Mg-Fe-HTLCs) were synthesized via hydrothermal method, and characterized by XRD and FT-IR. The roasted products were used to remove sulfate ions by the adsorptive ability from aqueous solution. The effects of adsorbent dosage, initial pH and temperature on the sulfate ions removal were fully investigated, and the adsorption kinetics and adsorption isotherms were also studied. Results showed that the synthesized materials with CO32- as the interlayer anions had fine crystallinity. The materials of Mg-Fe hydrotalcite-like compounds had a very good adsorption capacity for aqueous solution with the initial sulfate ions concentration was 500mg/L, pH range from 4 to 8 and temperature of 35°C. Moreover, the adsorption equilibrium was about 90 min under the optical condition. The experimental data showed a good compliance with the pseudo-second-order kinetic model, and the adsorption isotherm data met Langmuir models well. It was found that the maximal adsorption capacity reached 151.51mg/g.

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