Published Journal Articles
Optimization of New Sample Preparation Technique for the Determination of Methadone and Codeine in Plasma Sample by GC-FID
J. Braz. Chem. Soc. (Issue : 31) (Volume : 3)
A continuous sample drop ﬂow microextraction (CSDF-ME) technique was modiﬁed for the pretreatment of plasma samples in the determination of methadone and codeine. The limit of detection and linear range for methadone were 15.0 µg L−1 and 0.1-10.0 mg L−1, respectively. The detection limit and linear range for codeine were 25.0 µg L−1 and 0.2-15.0 mg L−1, respectively. The extraction recoveries were 41.6-52.1%, and the enrichment factors ranged from 65 to 80 for codeine and methadone, respectively. Intra- and interday precisions of the technique were calculated for codeine and methadone concentrations of 0.4 mg L−1 and were 4.2-7.6% and 2.5-5.1%, respectively. Also, the accuracy (error%) of method was in the range −10 to +7.5%. The applicability of the CSDF-ME-gas chromatography-ﬂame ionization detector (GC-FID) technique was illustrated by the determination of the mentioned drugs in human plasma. The attained relative recoveries of methadone and codeine in the 90.0-107.5% range demonstrated the excellent capability of the optimized technique for the microextraction of the mentioned drugs from plasma. The CSDF-ME-GC-FID is a rapid, repeatable and very simple technique that requires a low sample amoun
24 Determination of Dissociation Constants Of Malonic Acid in (Ethylene glycol-Water)X% mixed solvent At Different Temperatures Using electromotive force Measurements.
2019 IEEE, 2nd International Conference on Advanced Science and Engineering (ICOASE), Kurdistan Region, Iraq. (Issue : 2) (Volume : 1)
The first and second dissociation constants (pK$ & pK') of malonic acid in different composition of (ethylene glycol-water)%, (10, 20 and 30)% mixed solvent determined using the electromotive force measurements of galvanic cells without liquid junction at nine different temperatures, (278.15 − 318.15)K at 5° interval, including the body temperature. The value of the first and second thermodynamic dissociation constants have been used to determine the thermodynamic quantities of two dissociation processes. These quantities involved the standard free energy, ΔGo, standard enthalpy change, ΔHo, standard entropy change, ΔSo, and standard heat capacity change, ΔCpo
EVALUATION OF CRUDE OILS AND NATURAL GASES OF KURDISTAN-IRAQ BY CATALYTIC IMPROVEMENTS TO LIGHTER OILS USING LOCAL CLAYS
Ecology and the Environment (Issue : 81) (Volume : 222)
The chemical and physical properties of three different crude oils and two natural gas wells in Kurdistan-Iraq have been studied according to American Standard Test Method (ASTM) methods. Auto-distillations have been used to determine the changes in each cut, and gas–liquid chromatography has been used to find the approximate chemical constituents. A distribution diagram of paraffin, naphthenic, and aromatic hydrocarbons has been created. The gasoline cuts for each crude oil have been examined to find suitable octane additives (oxygenated or metal organic). The octane number increases as a function of the amount of additives, which has been plotted. A correlation between the trace metals and the types of hydrocarbons has been carried out for each crude oil. The improvement of these crude oils is achieved catalytically by reactions at high temperatures using different local clays, which gave us increases in lighter molecules by 7% (max). Chemical reactions are suggested for this improvement. X-ray analysis is also performed for each clay. Research is carried out on one gas–liquid well (Khor Mor) and another pure natural gas well. Gas chromatography analysis for Khor Mor shows 51% C1– C5 and 49% C6–C11, while other natural gas wells contain 98% methane. The natural gas of the Kirkuk wells contained approximately 10–12% hydrogen sulfide, which we separated using ethanolamines, and converted to hydrogen fuel and sulfur at two pilot plants using a new catalyst instead of the previous Clause process, producing about 143 tons of hydrogen per day.
8- Spectrophotometric determination of Calcium with 1-(2-Pyridylazo)-2-Naphthol Sensitized by Tween 80, Application to Various Samples.
IOP Conf. Series: Materials Science and Engineering 454 (2018) 012033 doi:10.1088/1757-899X/454/1/012033 (Issue : 454) (Volume : 1)
Spectrophotometric method for determination of Ca in aqueous solution using 1-(2- pyridylazo)-2-naphthol (PAN) as colour reagent has been developed. The method was based on the formation of Ca-PAN complex at pH 12 and measuring absorbance at 550nm, with molar absorptivity of 1.70x104 L.mol-1cm-1, average recovery is 101.72 and precision (RSD) is better than ±2.8% indicating that the method is relatively sensitive, accurate and precise. The binary system of Ca(PAN)2 and conditional stability constant of 1.467x1010 L2.mol-2 adherence of Beer’s law over concentration range 0.08-2ppm. The method was applied for the determination of Ca in natural water, milk, yogurt, human serum, grip and tomato juice satisfactory. In presence of 1% tween 80 and composite masking agents of pH 11.5 the absorbance measurements were made at 540nm giving molar absorptivity of 2.7x104 L.mol-1 cm-1 , average recovery of 101.2 and precision (RSD) better than ±3% indicating that the Ca(PAN)2 system is sensitive, accurate, and precise. In addition it is considered to be simple, rapid and do not need heating or solvent extraction steps, moreover it can be applied successfully for the assay of Ca in various samples over concentration range of 0.0008-0.8ppm.
10- Standard Potential of the Silver-Silver Chloride Electrode in X% Ethylene Glycol - Water Mixtures at Different Temperatures.
2018 IEEE, International Conference on Advanced Science and Engineering (ICOASE), Kurdistan Region, Iraq (Issue : 1) (Volume : 2)
The physical properties (density, viscosity, and dielectric constant) of five different compositions (0, 10, 20, 30, and 40%) of ethylene glycol-water mixtures have been measured at nine temperatures from (278.15 to 318.15 K) which were utilized to calculate the standard potentials of the Silver-Silver Chloride electrode and the mean activity coefficient of ten different concentration of HCl ranged from (0.01-0.1m). The modeling of the investigated system was made based on an extended Debye-Hückel equation, using Galvanic cell without liquid junction 𝒑𝒕,𝑯𝟐(𝒈,𝟏𝒂𝒕𝒎)│𝑯𝑪𝒍(𝒎),𝑬𝑮+𝒘𝒂𝒕𝒆𝒓│𝑨𝒈𝑪𝒍(𝒔),𝑨𝒈. The standard potential at different temperatures were utilized to calculate the standard thermodynamic quantities Δ𝑮°,Δ𝑯°,𝒂𝒏𝒅 Δ𝑺° for the cell reaction. The results discussed in concerning with acid-base properties, solute-solvent interactions and the breakdown of the water structure on the addition of ethylene glycol.
Semi-automated continuous sample drop flow microextraction with swift preconcentration and atomic absorption spectrometry determination of lead in water and apple leaves
Journal of the Iranian Chemical Society (Issue : 10) (Volume : 3)
In this paper, we present novel developments to our recently developed method so-called “continuous sample drop flow microextraction (CSDF-ME)” technique. Previously, we showed that the CSDF-ME technique offers several advantages, including stability of extraction solvent, no need for holder device, and easy to operate. The merit of current study is to make the extraction steps faster with sample required for the analysis. The key novelty of proposed method includes usage of a solvent mixture (i.e., methanol and carbon disulfide), allowing to pump aqueous samples with a higher flow rate than the former technique which led to reduce the extraction time. Results show that the technique is cable to become faster by five times with an enrichment factor of 93 for 4.0 mL of aqueous sample. The linear range and limit of detection for Pb are found to be 0.1–6.0 and 0.03 µg L−1, respectively. The relative standard deviation for determination of 1.0 µg L−1 of Pb in a sample is 2.9% (n=5). Furthermore, the relative recoveries of the developed CSDF-ME method for Pb in tap water, mineral water, and Standard Reference Material for apple leaves (1515) are shown to be 98, 100, and 94%, respectively.
5- Flow – Injection Spectrophotometric Determination of Calcium using Bromopyrogallol Red (BPR) as a Color Agent
Indian Journal of Natural Sciences (40),11972-11977, 2017 (Issue : 40) (Volume : 4)
This study investigates FI spectrophotometric determination of calcium using bromopyrogallol red has been developed. A calcium solution injected into KCl-NaOH buffer (pH 11.6) and then merged with the aqueous BPR (11.00 x 10-4 M) and continuously monitored sample. The linear range for the determination of Ca obtained under the optimum conditions was 1–10 mg Ca L-1. The average sampling rate was 240 samples/hr. The precision is in between 1.7-2.6% RSD and the accuracy (average recovery) of Ca is 102%, indicating that the method is sensitive, precise, accurate, and rapid.The proposed procedure has been validated by using reference materials and comparing the results with the standard methods. The “t”-exp values are found to be less than the “t”-table, indicating that the present method has a good validity and then applied to blood serum, natural waters, milk, and yogurt.
FIRST DERIVATIVE SPECTROPHOTOMETRY FOR SIMULTANEOUS DETERMINATION OF IRON AND CALCIUM USING BROMOPYROGALLOL RED.
International Journal of Advanced Research 5(8), 1686-1691 (Issue : 8) (Volume : 5)
Bromopyrogallol Red (BPR) as analytical reagent has been used for simultaneous determination of iron and calcium using first-derivative spectrophotometry. The zero - crossing technique was employed using first-derivative for Fe-BPR and Ca-BPR at 600 nm and 558 nm respectively. The linear relationship for Fe and Ca determination obeys beer's law from 0.2-1.2 µg/ml and 0.2-1.0 µg/ml respectively. The proposed method should be useful for accurate, precise, and rapid determination of iron and calcium in various samples with percentage recovery of about 101%. The stability constants (mean of three values) were found to be 1.33×108L2.mol-2 and 9.13 × 1011 L2mol-2 for Fe-BPR and Ca-BPR complexes respectively which indicates that the complexes are stable
Building a Visible Light Spectrophotometer From NaI Detector
Asian Journal of Chemical Sciences 2(2): 1-7, 2017; Article no.AJOCS.32418 (Issue : 2) (Volume : 2)
A fluorescence spectrometer is used in the Measurement of a broad range of applications. The main parts of spectrometers are the photocathode connected to photomultiplier and the multichannel scalar (MCS) for Lifetime Measurements in Nanosecond to Seconds Range and multichannel analyzer (MCA) for the intensity and wavelength of UV/V light. There is a wide range of sensors for light sensing applications: from a photomultiplier tube which gives a large voltage pulse for every photon it detects, to cooled thermopiles that absorb kilowatts of power. The aim of this work is to develop and introduce Single Photon Detector as fluorescence spectrometer and chemiluminescence kinetics. For this purpose, the NaI crystal is removed gently from the detector cavity, used in gamma spectroscopy, so that the bare photocathode remained sealed to the photomultiplier. The capability of the system is mainly dependent on the sensitivity of the photocathode. The system is investigated to find a calibration curve of standard solutions. First, Original Research Article Abdullah et al.; AJOCS, 2(2): 1-7, 2017; Article no.AJOCS.32418 2 applying UV/V atomic absorption spectroscopy and measuring the time course of fluorescence signal from chemiluminescence absorbance. The results obtained are very encouraging to move forward towered more applications.
FLOW INJECTION ANALYSIS OF HYDROGEN PEROXIDE WITH PEROXYOXALATE CHEMILUMINESCENCE DETECTION
Sience Journal of University of Zakho Vol. 5, No. 1, pp. 88 –92, March-2017 (Issue : 1) (Volume : 5)
This study reports a new, rapid and sensitive flow injection analysis (FIA) with peroxyoxalate chemiluminescence detection (POCL) for determination of hydrogen peroxide through merging zone principle. Di (N-Succinimidyl) oxalate was applied for the first time as peroxyoxalate chemiluminescence reagent. The CL was produced by the oxidation of Di (N-Succinimidyl) oxalate by hydrogen peroxide in the presence of a fluorescent compound, (9, 10 Bis phenyl ethynyl anthracene) and imidazole as a catalyst. Various parameters associated with this flow system were studied and essential optimizations were carried out. Calibration graph was constructed for determination of hydrogen peroxide in the range (0.02-0.34 mol.L–1) with correlation coefficient (R2) (0.982).The method was applied successfully for the determination of hydrogen peroxide in commercial pharmaceutical products and in tap water.
SYNTHESIS AND CHARACTERIZATION OF PHOTOCATALYTIC PERFORMANCE OF RUTILE-TIO2 NANOROD ARRAYS FOR SOLAR HYDROGEN GENERATION
Science Journal of University of zakho (Issue : 1) (Volume : 5)
Single crystalline rutile TiO2 nanorods (TNRs) films have been grown on the fluorine doped tin oxide (FTO) substrates using a one pot hydrothermal method, have attracted great attention because of favorable applications in the photoelectrochemical water splitting system. The effect of the reaction conditions on the morphology, crystal orientation and photocatalytic activity has been systematically investigated. The X-ray diffraction (XRD) pattern shows that two diffraction peaks at 36.3° and 63.2° correspond to the (101) and (002) planes of the tetragonal rutile TiO2 nanorod, respectively. The scanning electron microscope (SEM) of the samples indicates that the TiO2 array surface morphology and orientation are highly dependent on the reaction parameters, such as temperature, reaction time and the titanium precursor concentration. In a typical condition of the hydrothermal method at 0.3ml of TBO and 160°C for 3 hr, a small diameter and short length 190 nm and 2.2 µm of TiO2 nanorods respectively, are grown on florien doped tin oxide (FTO) substrate. When synthesized TiO2 nanorods photocatalyst was irradiated under illumination of simulated AM 1.5G solar light (100 mW cm−2) achieves an overall Photocurrent density of 1.80 mA/cm2 with a maximum photoconversion efficiency of ~1.6%. The results suggest that these dense and aligned one-dimensional TiO2 nanorods are promising for hydrogen generation from water splitting based on PEC cells.
Design and construction of electrochemical selective sensors for copper(II) in water samples based on C18H18N6S2 and C4H8O4S2 Dithio ligands as neutral carriers
International Journal of Advanced and Applied Sciences (Issue : 12) (Volume : 3)
Dithio based chelating ionophores such as 1-anilino-6-(3, 4-xylyl)-2, 5- dithiobiurea (A) and Dithiodiglycolic acid (B) were used as active components of PVC membrane electrode and explored as Cu2+-ion selective electrodes. The membranes having the composition (A): o-nitrophenyl octyl ether (o-NPOE): polyvinyl chloride (PVC): potassium tetrakis(4- chlorophenyl) borate (KTpCIPB) in the ratio of 3: 78: 40: 2 (w/w; mg) and (B): (o-NPOE): (PVC): (KTpCIPB) in the ration 3 :80 :40 :3 are found to be exhibiting the best sensor characteristics. The fabricated sensors exhibited Nernstain response (29.301 and 28.223 mV decade-1) over concentration ranges of 1.0 × 10-8 to 1.0 ×10-1 mol/L and 1.0 × 10-7 to 1.0 ×10-1 mol/L and exhibit detection limit of 2.2 × 10-8 and 8.3 × 10-7 mol /L for sensor No. 9 and 6 for ionophores A and B, respectively. The best performances were observed with the sensor having the composition of (A): (o-NPOE): (PVC): (KTpCIPB) in the ratio of 3: 78: 40: 2 (w/w; mg), and the electrodes have a response time of 9 - 12 s with a pH range of 3.0 - 7.0, and could be used over a period of 3 months without any significant deviation in its potentiometric characteristics. The analytical usefulness of the proposed sensor has been evaluated by its application in the determination of copper in water samples, the results obtained by the proposed ISEs are in good agreement with the results obtained by direct flame AAS method. The sensor No. 9 has been used also in the potentiometric titration of Cu2+ with EDTA.
DETERMINATION OF THERMODYNAMIC STABILITY CONSTANTS FOR 1:1 COMPLEXES OF CU(LL) WITH 2-HYDROXYBENZOIC ACIDS IN AQUEOUS MEDIA USING CU(II) ION SELECTIVE ELECTRODE
Academic Journal of Science (Issue : 2) (Volume : 2)
A systematic study for the effect of substituents on the thermodynamic stability constant of 1:1 complexes of Cu(ll) with six monosubstituted 2-hydroxybenzoic acids was carried out in aqueous media (deionized water) using Cu(II) ion selective electrode [ Cu(ll) ISE ]. Calibration of the electrode with standard solutions of Cu(II) perchlorate ( 10-2 to 10-6 mol/dm3) using the standard double junction silver / silver chloride reference electrode gave the best Nernstian response ( correlation of emf with pCu ). The test solutions [ containing Cu(ll) ions, ligand and base] were prepared and the equilibrium cell emf for each solution was measured at five temperature. For best precision, optimum conditions were selected (for each test solution) to give a sufficiently higher potential [higher free Cu(ll) activity] than that of the detection limit of the electrode. The equilibrium hydrogen ion concentrations of the test solutions were calculated from the electroneutrality principle and compared with that obtained from measured pH at 25°C. The data (various concentrations used in each test solution and measured emf) were fed into computer programs to perform all the calculations needed as well as those for thermodynamic stability constants and thermodynamic functions G°, H°, and S°. The high negative values of G° indicate that the complexing process is spontaneous and stable. The negative values of S° show that entropy is not in favor of the reaction to form the complex. However, the highly negative values of H° indicate that enthalpy is the strong driving force for the formation of the complexes. A thermodynamic treatment for the substitution has been presented and a correlation between logS (where S is the stability constant of the complex) and pK2 (where K2 is the second ionization constant of the acid) gave a good straight line whose correlation coefficient, slope, intercept and standard deviation in logS are 0.994, 0.8005±0.044, 2.1454±0.575 and 0.00109 respectively. Since the slope is 0.8005, it is concluded that substitution affects the Cu(ll) ion in these complexes to become as a -electron doner.
FIA-CL DETERMINATION OF PARACETAMOL USING LUMINOL– KMNO4–PB POST-CL SYSTEM, APPLYING MERGING ZONE PRINCIPLE
Journal of University of Zakho (Issue : 2) (Volume : 1)
This paper reports a new and simple flow injection analysis (FIA) with post- chemiluminescence system (PCL) for determination of paracetamol through merging zone principle. The method was based on the inhibition of luminol– KMnO4–Pb post- chemiluminescence (PCL).Various parameters associated with this flow system were studied and essential optimizations were carried out. Calibration graph were constructed for determination of paracetamol in the range (5.0–30) μg.ml-1 with correlation coefficient (0.996) .The method was applied successfully for the determination of paracetamol in commercial pharmaceutical products.
15- Dissociation Constants of Malonic Acid in X% Glycerine Water Mixtures at Different Temperatures using E.M.F. Measurements
Polish J. of chemistry 65, 1563 (1991) (Issue : 65) (Volume : 11)
The first and second thermodynamic dissociation constants of malonic acid in (10, 20, and 30) weight percent of glycerine in water have been determined at nine temperatures from 5˚C to 45˚C using electromotive force (e.m.f.) measurements of cells without liquid junction consisting of hydrogen and silver- silver chloride electrodes. The results have been used to derive the changes of the standard free energy (∆G˚), enthalpy (∆H˚) and entropy (∆S˚) as well as of the heat capacity (∆Cp˚) for the two dissociation processes in the mixed solvent. The dissociation of malonic acid is directly related to the temperature from 5 to 45˚C, and the PK1 & PK2 values increase with the increase of (X%) of glycerine – water mixture. The ratio K1/K2 for malonic acid in the solvent mixtures increases with the increase of the (x%) because of stability of intramolecular H-Bonding in monoanion of the acid when Glycerine is added to the water and decreases with increase of the temperature. The thermodynamic quantities of dissociation (∆G˚, ∆S˚, ∆H˚, ∆CP˚) of malonic acid increase with increase of the (X%) for glycerine – water mixture and with the increase of temperature
17- Studies on some complexes of strontium oxalate with aliphatic amines
Polish J. of chemistry 65, 1563 (1991) (Issue : 65) (Volume : 1)
Strontium is known to form complexes e.g. with B-diketones, their stability constants and thermogravimetric analysis were studied. However, there are no references in the literature concerning the preparation and characterization of strontium complexes with oxalic acid and aliphatic amines. We wish to report here the synthesis and characterization of such complexes.
2- Thermoanalytical investigations on heterocyclic organic compounds: Part VI. Synthesis, characterization and thermal decomposition of 1, 4-bis (p-fluorobenzene sulphonyl)-2-Alkoxytetrahydropyrazine.
Thermochimica acta 177, 329-339 (1991) (Issue : 177) (Volume : 6)
Seven derivatives of 1,4 bis (p-flourobenzene sulphonyl) 2-alkoxy tetrahydropyrazines with different alkoxy groups, amyl, n-butyl, 2-butyl, i-butyl, i-propyl, cyclopentyl, and cyclohexyl are synthesized by reaction of ....
18- Excess free enthalpy in chemically deposited silver metal films
Iraqi J. of chemistry, Vol 15, No.(3) 1990 (Issue : 3) (Volume : 15)
One of the best and most capable method for measuring the excess free enthalpy in metals is the measuring of the electromotive force (EMF) of an electrochemical cells containing well crystallized metal massive electrodes and metal film electrode. The source of the excess free energy is the presence of the structural defect. It is amount is related to the type of defects and their densities in the solid material directly. The EMF of silver films deposited on glass and mica sheets against silver massive electrodes has been measured as a function of substrate temperature and film thickness. The measured EMF values were in the range of 7-65 mv. The microscopic investigations were also carried out on freshly and aged films.
21- Effect of 2-Methoxy Ethanol as solvent on fluoride ion selective electrode
ZANCO Journal Pure and Applied Sciences 2 (2), 1988 (Issue : 2) (Volume : 2)
At constant fluoride ion concentration (10-9 M) the systematic change in cell potential (E) with variation in the concentration of water in 2-methoxyethanol - water mixtures, using fluoride ion selective electrode and calomel reference electrode provides a graphical method for rapid water dtermination in 2-methoxyethanol. Readings obtained by direct potentiometry show good reproducibility and stability. The response of fluoride ion selective electrode in 2-methoxyethanol-water mixture was studied using direct potentiometric method.
20- Effect of microwaves heat on ground nuts sterols
Iraqi J. of Agriculture Science, M/6, 79-89, 1988 (Issue : 6) (Volume : 79)
Gas-liquid chromatography separation of whole groundnuts unsaponifiable matter revealed twenty possible compounds. Twelve compounds were identified as sterols representing 80.61% of the unsaponifiable matter. Roasting and blanching of groundnuts were effective in lowering the concentration of some didstinctive sterols which in turn increased the concentration of other sterols. Effect of microwave heat at 12% moisture content was less effective on sterol distruction than 6% and both roasting and blanching . This would encourage the use of microwave heat at slightly high moisture content to preserve sterols and reduce suseptibility of groundnuts oil towards autoxidation and maintain optimum organoreptic properties.
22- Acidic Dissociation Constants of Glutaric Acid in Aqueous 1.3-Dimethyl urea from E.M.F. Measurements
Iraqi J. science 24 (2), 1983 (Issue : 24) (Volume : 2)
The first (K1) and second (K2)acidic dissociation constants of glutaric acid in 11.5% by weight 1,3-dimethylurea in water have been determined from e.m.f. measurements of cells without transference. The lowest K1 andK2 values, over the ezperimental temperatures from 278.15 to 318.15 K, were those obtained at 298.15 K. The value of K1/K2 in the present workwas 27 as compared with 12 in water. The results have also been used to calculate the standard changes of enthalpy, entropy, and heat capacity for twodissociation processes in