د. ابتهاج رحيم علي الشرماني

A new trend in extraction and preconcentration of chromium (VI) using laboratory-made azo dye reagent 2-[benzenethiazolylazo]-4-benzenenaphthol (BTABN) after cloud-point extraction (CPE) and its determination by spectrophotometrically. The method involved the reaction of Cr 2 O 7 2-with BTABN in acidic medium forming a hydrophobic ion-association complex [HBTABN][HCr 2 O 7 ] which is entrapped into micelle-mediating solvent (Triton X-100) and the Cr(VI) detected spectrophotometrically at λ max of 475 nm. The effect of the several factors on the CPE efficiency is optimized by one-factor-at-a-time (OFAT). Extensive thermodynamic study has been presented to understand the mechanism of extraction and solubilisation of ion-association complex in micelles. The interferences effect of divers ions is also considered. Under the optimized conditions, enrichment factor of 270 is achieved leading to limit of detection and limit of quantitation of 0.017 and 0.0568 μg mL-1 respectively. The linearity of 0.1-2.0 μg mL-1 and sensitivity in term of molar absorptivity is 4.47x104 L.mol-1 .cm-1 are obtained .The precision (RSD%; n=7) of the proposed method is of 0.31% % at 2.0 μg Cr (VI) mL-1. This method is applied in the determination of Cr (VI) in various environmental and botanical samples. Abstract-A new trend in extraction and preconcentration of c​h​r​o​

A new procedure for the separation, preconcentration and determination of cadmium as a chloro anion was presented by using the combined cloud point extraction (CPE) methodology and molecular spectrophotometry. The extraction process involved the conversion of cadmium (II) ion in acidic aqueous solution into chloro anion [CdCl4]2-complex and subsequently the hydrophobic ion-pair complex formed with crystal violet (CV) cation was extracted into the nonionic surfactant (Triton X-100) rich phase at a temperature above its cloud point (CPT). After phase separation, the surfactant-rich phase was diluted with ethanol and cadmium (II) ion determined by UV-Vis spectromphotometric technique at λmax of 449 nm. The optimization of complexation and extraction conditions was investigated. Thermodynamic parameters of CPE for solubilization process of the ion-pair complex in Triton X-100 were also considered. Under the optimized conditions, the preconcentration of a 10 mL sample gave preconcentration and enrichment factors were of 125 and 150 respectively. The calibration graph was linear in the range of 0.25-5 μg mL-1 with a correlation coefficient of 0.9995 and limit of detection of 0.042 μg mL−1. The relative standard deviation for replicate determinations at (3) μg mL−1 level was of 2.68%. The proposed method was applied for the determination of cadmium in soil, vegeTables, plant leaves and water which gave satisfactory results relative to results obtain by AAS method (2) (PDF) Cloud Point Extraction and Micro Amount Determination of Cadmium as Chloro Anion Complex in Real Samples by using Molecular Spectrophotometry. Available from: https://www.researchgate.net/publication/296196181_Cloud_Point_Extraction_and_Micro_Amount_Determination_of_Cadmium_as_Chloro_Anion_Complex_in_Real_Samples_by_using_Molecular_Spectrophotometry [accessed Sep 29 2019].

After pinpoint all optimum conditions for extraction Cobalt(II) as ion pair association complex or chleated complex with complexing agent 1-[2-pyridyl azo] -2-naphthol which dimonirtrate λmax for complex extracted was (446nm.) more stable complex formation was at pH= 7 and 60 μg Co(II)/5ml with 1×10-4 M 1-[2-pyridyl azo] -2-naphthol[PAN] dissolved in chloroform and shaking time 10 minutes. The stoichiometry of complex extracted to the organic phase was 1:1 metal : PAN [Co(PAN)+Cl- ] or [Co(PAN)] +(Cl-).Extraction method was endothermic as well as thermodynamic parameters after calculated was ∆Hex= 0.0149 KJmol-, ∆Gex= -58.81 KJ mol- and ∆Sex= 176.55 J mol-. Synergism study show from the slope is appear there is one molecule of TBP or MIBK participated in the structure of complex extracted to the organic phase. (PDF) Organic Solvent Effect, Thermodynamic Study and Synergism Behavior for Extraction Efficiency of Cobalt (II) Complex with 1-[2-Pyridyl Azo] -2-Naphthol. Available from: https://www.researchgate.net/publication/299606223_Organic_Solvent_Effect_Thermodynamic_Study_and_Synergism_Behavior_for_Extraction_Efficiency_of_Cobalt_II_Complex_with_1-2-Pyridyl_Azo_-2-Naphthol [accessed Sep 29 2019].

A new and versatile procedure for the spectrophotometric determination of manganese using micelle-mediated extraction was developed. The method involved the formation of an ion association complex between manganese oxyanion (MnO4-) and brilliant green in acidic solution and the complex was extracted into the surfactant Triton X-100 at optimum conditions. The surfactant-rich phase which contains manganese complex was mediated with solvent and the Mn content measured spectrophotometerically at absorption maximum (λmax = 657 nm). The effects of the several variables which impact the CPE efficiency were optimized by one-factor-at-a-time (OFAT). Under the optimized conditions, enrichment factor of 282 was achieved leading to limit of detection and limit of quantitation of 0.086 and 0.242 μg mL-1 respectively, with linearity of 0.2-3 μg mL-1. The precision (RSD%) of the proposed method was of 1.07% . The interferences effect of such ions was also studied. This method is applicable in the determination of manganese in environmental and vital samples (2) (PDF) A New Approach for Extraction and Determination of Manganese in Environmental Samples Using Cloud-Point Extraction Coupled with Spectrophotometry. Available from: https://www.researchgate.net/publication/293485192_A_New_Approach_for_Extraction_and_Determination_of_Manganese_in_Environmental_Samples_Using_Cloud-Point_Extraction_Coupled_with_Spectrophotometry [accessed Sep 29 2019].

A new chelate complexes of Co(II),Ni(II),Zn(II) and Cd(II) were prepared by reacting these ions with the ligand 2-[4- Carboxy methyl phenyl azo]-4,5-diphenyl imidazole (4CMeI) The preparation were conducted after fixing the optimum conditions such as (pH) and concentration .UV- visible spectra of these complex solutions were studied for a range of (pH) and concentration which obey lampertBeers Law.The structures of complexes were deduced according to mole ratio method which were obtained from the spectroscopic studies of the complex solutions .The ratios of metal: ligand obtained were (1:2) for all complexes..(UV-Vis) absorption spectra and The infrared spectra of the chelating complexes were studied ,this may indicate that coordination between the metal ions and our ligand takes place.The conductivity measurements , elemental analysis ,the percentage of some metal ions and the measurements of magnetic susceptibility of the complexes were determined ,Depending on these results , in addition to, We may conclude that the ligand was bidentate Also the proposed geometrical structures of the complexes of Co(II), Ni(II), Zn(II) and Cd (II) ions are octahedral.

Hetero cyclic azo ligand synthesized in previous study (Ali), use as an extractant for Cu2+ and Ag+ from aqueous solutions, and this study appear that the optimum pH for extraction was pH=8 for Cu2+ and pH=10 for Ag+, more probable structure of ion pair complex extracted was (1:2) for Cu2+ with sandwich structure [Cu(3-MeBAI)2]+2 anion and (1:1) for Ag+ [Ag(3-MeBAI)]+anion and another studies about the effective parameter on the extraction procedure and stability of complex.