2023-12

Iranian Journal of Catalysis (Issue : 11) (Volume : 4)

The goal of this research is to create nanostructured metal free phosphorous doped Boron nitride (P-BN) and phosphorous-carbon co-doped Boron nitride (CP-BN) that serve as photocatalysts when exposed to UV light. P-NPs were well diffused in aqueous solution. The nanostructured materials were characterized using XRD, SEM-EDX, and UV-Vis spectrophotometry. Based on the characterization results, phosphorous atoms were doped in the crystal structure of BN. The experimental data and theoretical calculations were used to measure the band gap energy, which was determined to be around 4.2 eV in the experimental case; for this purpose, both Tauc and Kubelka-Munk equations were utilized. Thus, photocatalysis degradation is limited to UV region. To examine the degradation effectiveness of photo-catalysts, toluidine blue (TB) was utilized; it was found that the basic medium was the best for degradation; 16% and 8% of TB were eliminated with CP-BN and P-BN, respectively after one hour degradation. Scavengers such as IPA, Na2C2O4, KBrO3, and ascorbic acid were added to trapping experiments to demonstrate the correct potential energy gap in valance and conduction bands and possible photocatalytic mechanism. Data from trapping experiments show that both the hydroxyl radical and super oxide are responsible for degradation, but electron and hole at valance and conduction bands were of low efficiency because of quick recombination. As regards computational study, the crystal and electronic structures of the P-BN and CP-BN have been studied. The lattice parameters were calculated with the Perdew-Burke-Ernzerhof (PBE), and the bandgaps (Eg) were calculated with the (PBE) as (non-local) instead of local (non-local functional generalized gradient approximations) (GAA). In addition, hybrid functional was also applied including (Becke-3 Parameter-Lee-Yang-Parr) B3LYP and (Heyd–Scuseria–Ernzerhof) exchange–correlation functional HSE06. Hybrid functional B3LYP provided better results and closer to the experimental data of the P-BN and CP-BN compound.

2023-06

Eurasian J. Sci. Eng. (Issue : 2) (Volume : 9)

Many products labeled as "traditional herbal remedies" have a lengthy history of usage by definition of the term "traditional." Large segments of the population in many developing countries rely on traditional healers and their arsenal of medicinal plants to meet their healthcare requirements. Because of historical and cultural factors, herbal treatments are still widely used in modern medicine despite their antiquity. In industrialized nations, such things have become more accessible commercially. Current medical systems frequently recommend using chemicals in ways they weren't designed to be used. In certain parts of the world, the manufacture of herbal medicines are subjected to tight regulations, but this is not the case in other parts. In Germany Pharmacological goods are bound to the same criteria of efficacy, safety, and quality as herbal remedies, they are sold as "phytomedicines. On the other hand, most herbal products are marketed and monitored as food supplements in the United States, no pre-approval is required for this product category in the United Kingdom. As numerous academics in Iraq and the Kurdistan area have indicated, herbs have been utilized as a traditional cure for a wide range of illnesses in the past. Tribulus terrestris, Artemisia splendens Willd, Crataegus azarolus, Teucrium chamaedrys, Adiantum capillus-veneris and Matricaria chamomilla are the herbs discussed in this study, and their medicinal and traditional usage across the world, as well as some of the chemical components in these herbs' biological activity, are discussed.

2023-04

RSC advances (Issue : 10) (Volume : 13)

To achieve the efficient removal of pharmaceutical wastes, novel photo-Fenton catalysts, iron-decorated boron nitride quantum dots (Fe@BNQDs) were prepared. Fe@BNQDs were characterized using XRD, SEM-EDX, FTIR, and UV-Vis spectrophotometry. The decoration of Fe on the surface of BNQDs enhanced the catalytic efficiency due to the photo-Fenton process. Photo-Fenton catalytic degradation of folic acid was investigated under UV and visible light. The influence of H2O2, catalyst dose, and temperature on the degradation yield of folic acid was investigated using Response Surface Methodology. Moreover, the efficiency of the photocatalysts and kinetics was investigated. Radical trapping experiments revealed that holes were the main dominant species in the photo-Fenton degradation mechanism and BNQDs played active roles because of their hole extraction ability. Additionally, active species such as …

2023-02

Analytical Sciences (Issue : 6) (Volume : 39)

In this study, octanoic acid (OA) was used as an extraction solvent for the pre-concentration and determination of three antibiotic drugs (levofloxacin, metronidazole, and tinidazole) in urine samples. To extract the antibiotic drugs, a green solvent was used as the extraction solvent in the continuous sample drop flow microextraction method, followed by a high-performance liquid chromatography photodiode array detector. According to the findings, the present study offers an environmentally friendly analytical method with a high capacity for the microextraction of the antibiotic drugs at very low concentrations. The calculated detection limits were 6.0–10.0 μg/L and the linear range was found between 20 and 780 μg/L. The proposed method showed excellent repeatability with the RSD values ranging from 2.8 to 5.5%. The relative recoveries were between 79.0 and 92.0% in the urine samples with spiked levels of 40.0–100.0 μg/L for metronidazole and tinidazole, and 100.0–200.0 μg/L for levofloxacin. Keywords Green solvent · CSDF-ME · Antibiotic drugs · Urine · HPLC–PDA

2023-01

New J. Chem (Issue : 6) (Volume : 47)

In this study, we report the synthesis and application of a novel three-component deep eutectic solvent (DES) as a promising solvent for the extraction of antibiotics from wastewater and urine. The new DES is a mixture of choline chloride, octanoic acid and ethyl benzoate at a ratio of 1 : 20 : 13, which was employed as a solvent in the extraction of several antibiotics including metronidazole, tinidazole and levofloxacin from wastewater and urine samples using continuous sample drop flow microextraction (CSDF-ME) followed by HPLC analysis. Several characterization methods including FTIR, H-NMR and C-NMR were employed to identify and confirm the formation of the synthesized DESs. The results confirmed that the new DES could be used for reliable determination of the studied antibiotics by CSDF-ME-HPLC with limits of detection in the range of 3.0–6.0 mg L1. The calibration curves were linear between 12.0 and 780.0 mg L1, and repeated readings with the RSD% values ranging from 1.85% to 4.95% were obtained. The relative recoveries were between 84% and 115% for the water samples spiked with 12.0–100.0 mg L1 metronidazole and tinidazole, and 24.0–200.0 mg L1 levofloxacin.

2022-10

ACS Omega (Issue : 42) (Volume : 7)

In this paper, silver-loaded phosphorous and carbon co-doped boron nitride quantum dot (Ag@CP-BNQD) nanocomposites were synthesized using a co-precipitation method followed by a hydrothermal approach. The nanocomposites of Ag@CP-BNQDs were characterized by scanning electron microscopy, energydispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and ultraviolet−visible spectrophotometry. The as-prepared Ag@CP-BNQDs were used for photocatalytic degradation of 10 common organic pollutants, including dyes, pharmaceuticals, and pesticides in aqueous solution under visible light irradiation. The high-performance photocatalysis of Ag@CP-BNQDs proved that Ag@CP-BNQDs is plasmonic and the n−p junction photocatalyst. Theoretical calculations were done to measure the crystals and electronic structures of Ag@CPBNQDs. Theoretical results showed that loading of Ag behaves as plasmonic sensitizers and co-catalysts and provides extra bands, which make electron movement easier between valance and conduction bands. The mechanism of the charge separation enhancement was postulated. Our findings might deepen our understanding of how sensitizer surface modification works in photodegradation applications.

2022-10

journal of Basic Sciences (Issue : 13) (Volume : 8)

This research aims to examine heavy metals contents and environmental risk in the Khabur river water in Zakho-Iraq. Ten different locations were selected on the Khabur River from the beginning of its entrance into the Kurdistan region until it overlapped with the Tigris River at the triple border point (Iraq, Surya, and Turkey). Temperature, pH, electrical conductivity, dissolved oxygen, total dissolved salts, and turbidity were tested locally in the field. Inductively coupled plasma optical emission spectroscopy (ICPOES), flame photometer, and titration methods were used to analyses twenty-five metals in water samples. It was found that some heavy metals are undetectable such as Boron, Cadmium, Beryllium, Nickel, antimony, and selenium. Chromium was found in only one location with a concentration of 0.002 mg/L. Aluminum was found at higher than the acceptable levels in two areas with concentrations (0.215 and 0.1893 mg/L). Also, in two other points, Iron was found to be higher than the permissible level (0.397 and 0.311 mg/L). According to Iraqi and World Health Organization standards, other heavy metals were less than the affected value. The Water Quality Index (WQI) was calculated to evaluate water quality; the results shown water in one of the locations of the Khabur river was poor in quality, yet in other locations, it was good.

2021-01

Microchemical Journal (Issue : 1) (Volume : 160)

A simple, precise and sensitive analytical method, which is a combination of modified ultrasound-assisted extraction (UAE), continuous sample drop flow microextraction (CSDF-ME) and GC–MS, was developed for the extraction and determination of organophosphorus pesticides in fruit and vegetable samples. In this study, for the first time, a very small amount of organic solvent was used for the UAE, almost three times less than conventional UAE. To this end, first, the raw vegetables and fruits were finely chopped and mashed. Then, 0.8 mL of acetonitrile was added and the entire mixture was sonicated for 20 min. Afterward, in order to remove acetonitrile from the mixture and to reduce the amount of organic solvent 6.0 mL of ultra-pure water was added to the mixture, and the aqueous phase was filtered out. Next, the extracted analytes were concentrated by pumping the aqueous phase across a few microliters of organic solvent (chloroform) placed inside the bottom of a conical vial at a flow rate of 0.45 mL min􀀀 1. Finally, the extracted analytes were transferred into the GC–MS for further detection. Under the optimum conditions, the relative recovery ranged from 83.0% to 108.0%. The repeatability of the method was examined at two concentration levels (60.0 and 120.0 ng g􀀀 1), and it was obtained between 4.0 and 7.6%, and 3.2 and 6.2%, respectively (n = 5). Finally, the LOD and LOQ were found to be 0.2–20.0 ng g􀀀 1, and 1.0–60.0 ng g􀀀 1, respectively.

2021-01

Journal of Food Composition and Analysis (Volume : 95)

In this work, for the first time, low-density organic solvents were employed in continuous sample drop flow microextraction (CSDF-ME) by changing the design of extraction vessel. To examine the effectiveness of the modified extraction method, different organophosphorus pesticides (OPPs) were extracted using proposed method followed by detection by gas chromatography–mass spectrometry (GC–MS). In fact, unlike conventional CSDF approach, in this study, we applied halogen-free organic solvents that are lighter than water for analytes extractions. These solvents are not only less toxic but also more environmentally friendly compared to the halogenated solvents. A conical open-end vial fixed in a small container filled with double-distilled water was used as the extraction vessel. A small amount of extraction solvent was placed at the bottom of the vial and the sample solution was pumped into the extraction …

2021-01

New Journal of Chemistry (Issue : 1) (Volume : 45)

The [3+2] cycloaddition (32CA) reactions of N-benzylcyclohexylnitrone 1 with methyl-3-butenoate 2 have been studied within molecular electron density theory (MEDT) at the B3LYP/6-311++G(d,p) level of theory. These zwitterionic type 32CA reactions occur through a one-step mechanism. The 32CA reactions undergo two pairs of stereo- and regioisomeric reaction paths to form four different products, 3, 4, 5 and 6. The reaction paths are irreversible due to the exothermic character of −18.5 and −12.4 kcal mol−1. The 32CA reaction leading to the formation of cycloadduct 3 presents the lowest activation enthalpy compared to the other path due to a slight increase in polar character evident from the global electron density transfer (GEDT) at the transition states and along the reaction path. The bonding evolution theory (BET) study suggests that these 32CA reactions occur through the coupling of pseudoradical centers …

2020-11

Microchemical Journal (Issue : 11) (Volume : 160)

A simple, precise and sensitive analytical method, which is a combination of modified ultrasound-assisted extraction (UAE), continuous sample drop flow microextraction (CSDF-ME) and GC–MS, was developed for the extraction and determination of organophosphorus pesticides in fruit and vegetable samples. In this study, for the first time, a very small amount of organic solvent was used for the UAE, almost three times less than conventional UAE. To this end, first, the raw vegetables and fruits were finely chopped and mashed. Then, 0.8 mL of acetonitrile was added and the entire mixture was sonicated for 20 min. Afterward, in order to remove acetonitrile from the mixture and to reduce the amount of organic solvent 6.0 mL of ultra-pure water was added to the mixture, and the aqueous phase was filtered out. Next, the extracted analytes were concentrated by pumping the aqueous phase across a few microliters of organic solvent (chloroform) placed inside the bottom of a conical vial at a flow rate of 0.45 mL min􀀀 1. Finally, the extracted analytes were transferred into the GC–MS for further detection. Under the optimum conditions, the relative recovery ranged from 83.0% to 108.0%. The repeatability of the method was examined at two concentration levels (60.0 and 120.0 ng g􀀀 1), and it was obtained between 4.0 and 7.6%, and 3.2 and 6.2%, respectively (n = 5). Finally, the LOD and LOQ were found to be 0.2–20.0 ng g􀀀 1, and 1.0–60.0 ng g􀀀 1, respectively.

2020-11

Microchimica Acta (Issue : 12) (Volume : 187)

A novel aluminum terephthalate/Fe2O3 nanocomposite was synthesized by the addition of Fe2O3 nanoparticles into a reaction solution containing aluminum terephthalate MOF. The synthesized nanocomposite was successfully used as a fiber coating material for solid-phase microextraction (SPME) of six organophosphorus compounds (OPPs) from river water, grape juice, and tea samples. The effect of different parameters on the efficiency of SPME including desorption temperature and time, extraction temperature and time, salt concentration, pH, and agitation were thoroughly studied. The OPPs were detected and determined using GC-MS. According to the findings, a wide linear range (0.15–800 μg kg−1), low limit of detection (0.04–10 μg kg−1), and high recoveries from spiked samples (87.5–112%) were achieved with low inter-day relative standard deviation (3.2–6.7%, n = 5). The MIL-53(Al)/Fe2O3 …

2020-04

New Journal of Chemistry (Issue : 13) (Volume : 44)

The dispersibility of carbon dots in organic and/or aqueous solvents plays a critical role in various application fields. Amphiphilic carbon dots could find broader applications due to their hydrophilic and lipophilic properties. Here, a method is described for the preparation of amphiphilic carbon dots (CDs) from white berries as a carbon source. The CDs can be well dispersed both in organic and aqueous solvents. Fluorescence is strongly red-shifted upon going from an organic solvent (in CCl4 the emission is blue with a maximum at 450 nm) to an aqueous solvent (orange fluorescence with a maximum near 600 nm). Fluorescence is independent of the excitation wavelength which is uncommon in the carbon quantum dot family. Nitrite is found to quench fluorescence in water solution, but not other common metal cations and anions. In chloroform, the fluorescence is quenched by tetracycline. The linear part of the …

2020-03

Digest Journal of Nanomaterials and Biostructures (Issue : 1) (Volume : 15)

Using a microwave-assisted hydro thermal method (MWAHM) a single crystalline of vertically aligned TiO2 nanorod (NR) arrays has been achieved via the novel ultra-rapid synthetic method for the production. High-quality NR arrays with controlled film thickness were achieved with fine control of the growth conditions as well. The effect of the different reaction conditions of MWAHM such as reaction time and growth temperature on the morphology, crystal orientation, and photo catalytic activity have been systematically investigated. In a typical condition of the MWAHM using 0.4 cm3 of titanium(IV) n-butoxide (TBO) at 180 °C for 40 minutes, a small diameter of 124 nm and short length 2.93 μm of TiO2 nanorods, are grown on fluorine-doped tin oxide (FTO) substrate. However, the photo current density produced TiO2 NRs of 2.90 mA cm-2 with a maximum photo conversion efficiency of about 2.7% which confers excellent photoelectrochemical performance. In comparison with the typical hydro thermal method (HM) synthesized NRs, the ultra-fast MWAHM synthesized NRs offers five times more efficiency photoelectrochemical (PEC) water splitting than the hydro thermal method (HM). The results suggest that these dense and aligned one-dimensional TiO2 nanorods are promising for hydrogen generation from water splitting based on PEC cells.

2020-02

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

2020-02

Food Analytical Methods (Issue : 10) (Volume : 305)

In this paper, the technique of continuous sample drop flow microextraction (CSDF-ME) is developed by the addition of a narrow-necked conical vessel. In the developed technique, an organic solvent denser than water is used for the extraction of organophosphorus pesticides (OPPs) from fruit juice and river water, followed by analysis with GC-MS. Eight milliliters of the sample solution is pumped at 0.5 mL min−1 flow rate into 12.0 μL extraction solvent (chloroform) and placed in the narrownecked conical vessel for extraction and pre-concentration processes. Under optimal condition, the enrichment factor (EF) and linearity are found to be in the range of 102–380 and 500.0 μg L−1 with correlation coefficient greater than 0.98, respectively. The detection limit is in the range of 0.3–1.0 μg L−1 and LOQ ranged from 2.0–5.0 μg L−1. The relative standard division (RSD) of six replicate measurements for three different concentrations (i.e., 15.0, 50.0, 150.0 μg L−1) is 3.8–8.4%, 2.6–6.0%, and 2.2– 4.8%, respectively. Values of RSD% of the target pesticides at 50.0 μg L−1 concentration levels are less than 6.0%.

2019-04

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

2019-04

Recent Researches in Earth and Environmental Sciences: 2nd International Conference on Advanced Science and Engineering 2019 (ICOASE2019) Zakho-Duhok, Kurdistan Region—Iraq, April 2–4, 2019 (Issue : 4) (Volume : 2)

Hydrogen sulfide is very poisons gas it should be extracted from water and decomposed it to pure sulfur and clean Hydrogen fuel. We had been done the extraction of this gas in Black Sea using two types of pilot plants. This paper will focus on the extraction of low concentration of hydrogen sulfide (H2S) from Duhok Dam. Survey for the concentration of this gas is low (0.1–5 ppm) at different depth and region of the Dam that may be due to natural sulfur cycle of reducing and oxidizing bacteria in this dam. According to Le Chatelier’s principle the equilibrium concentration of H2S gas is about 0.5 ppm at depth of 15 m. A novel physical extraction method based on Henry’s law have been done outside water for stripping H2S completely from Dam water by special open pilot plant with tower at height between 10 and 15 m depending on the location of plants on the Dam producing cheap and continuous clean …

2019-01

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.

2018-10

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.

2018-09

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.

2018-06

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.

2017-09

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.

2017-08

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

2017-04

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.

2017-03

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.

2017-03

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.

2016-10

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.

2013-10

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.

2013-06

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.

1991-11

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

1991-09

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.

1991-06

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 ....

1990-06

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.

1988-09

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.

1988-06

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.

1983-06

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