Analytical chemistry
Amir Hosein Mohammad shafiee; Mohammad Reza Mohammad shafiee
Abstract
Due to the challenges of maintaining serum levels in a safe therapeutic range (1–3 μM), Clozapine is one of the most promising medications for managing schizophrenia. Recently the barrier to the broader use of clozapine has been recognized to be the measurement of clozapine levels, which is ...
Read More
Due to the challenges of maintaining serum levels in a safe therapeutic range (1–3 μM), Clozapine is one of the most promising medications for managing schizophrenia. Recently the barrier to the broader use of clozapine has been recognized to be the measurement of clozapine levels, which is however challenging due to the complexity of serum samples. The determination of clozapine is mainly conducted through a novel, simple, rapid and sensitive air assisted dispersive liquid-liquid microextraction based on solidification of organic droplet method that has been developed and validated by high-performance liquid chromatography with UV detection in human serum. In this method, due to the usage of an organic solvent with a low density and appropriate melting point, no microsyringe or fiber is required to support the organic microdrop. Furthermore, the extractant droplet can be collected easily by solidifying it at low temperature. 1-Undecanol was selected as extraction. The optimization of Parameters that influence extraction efficiency, i.e., volumes of extracting solvent, pH, and salt effect, were performed using a factor by factor approach. Enrichment factor for clozapine under optimal conditions was 128. The limit of detection was 1.34 ng/mL in serum sample. The proposed method was successfully applied to the determination of clozapine in serum samples of a person under clozapine therapy.
Analytical chemistry
Samson Abah Abagale; Sampson Atiemo; Felix Kofi Abagale; Alex Ampofo; Charles Yaw Amoah; Sylvanus Aguree; Yaw Osei
Abstract
Crops, soil and fish from irrigation farms were investigated in the Upper East Region of Ghana. Questionnaire was administered to collect pesticide use information from farmers, and tomatoes, okro, pepper and garden eggs as well as fish and soil samples were collected and analysed using Gas Chromatography-Electron ...
Read More
Crops, soil and fish from irrigation farms were investigated in the Upper East Region of Ghana. Questionnaire was administered to collect pesticide use information from farmers, and tomatoes, okro, pepper and garden eggs as well as fish and soil samples were collected and analysed using Gas Chromatography-Electron Capture Detector (GC-ECD). The results were compared with standard acceptable Maximum Residue Limits (MRLs). The results indicated that up to 35.9% of 50 respondent farmers frequently cultivated tomatoes. 50% of the farmers have been using agrochemicals for the past 5 years, with glyphosphate as the most commonly used (42%). 65 % of the farmers indicated that information on proper use or handling of agrochemicals was obtained from colleague farmers. High levels of organochlorine residues (2.232-5.112 ng/g) were found in okro and garden eggs from the Tono site, and also pepper and tomatoes from Pungu site. 6 pesticides residues were found in 5 varieties of tomatoes samples analysed with Lindane and Aldrin having the highest concentration of 0.00069 and 0.027 μg/g respectively. 4 soil samples contained detectable levels of β-HCH and α-Endosulfan (organochlorines), while all 6 samples had one or more traces of 10 organophosphate pesticides. Chlorpyrifos was widely available and in quite high levels. 21 organochlorine residues were detected in tilapia and mud fishes, 17 in fishes from the Precast yard water. Residual concentration of Aldrin and Cis-heptachlor (1069.7 ng/g and 780.7 ng/g respectively) in tilapia from the Tono dam was noted to be above the acceptable limits.
Analytical chemistry
Ogbuneke Christian Chika; Ezeibeanu Amara Prince
Abstract
The analysis of heavy metals in drinking water from different sources in Lagos state, Nigeria were determined with a view of comparing the effects of level of Industrialization, population density and urbanization on the water quality in the centre of Lagos and off town of Lagos (Ikorodu LGA, a relatively ...
Read More
The analysis of heavy metals in drinking water from different sources in Lagos state, Nigeria were determined with a view of comparing the effects of level of Industrialization, population density and urbanization on the water quality in the centre of Lagos and off town of Lagos (Ikorodu LGA, a relatively less Industrialized and less Urbanized town of Lagos state) as a case study. The different sources of drinking water considered were wells, boreholes, surface water and tap water. In each of Lagos and Ikorodu. The heavy metals were analysed; Pb, Cd, Cu, Fe, Cr, Zn, Na, Ni, Mg and Ca using Atomic Absorption Spectrophotometer (Perkin-Elmer 305B model with air-acetylene flame). The results show that Pb, Ni, and Mg values exceeded the permissible limits set by WHO, EU and NIS for all the samples from all the sources in all study area while Fe has values above the standards set by all the regulatory bodies in Ikorodu boreholes (i.e. 1.804 mg/L) but all other sources as well as all Lagos samples have values of Fe within the permissible limits (0.2-0.3 mg/L) and this could be traced to the geology of the area. Cu, Zn, Na, Cr, and Ca all have higher values in Lagos centre samples than in Ikorodu samples but are all within the permissible limits. Cd was not detected in any of the samples at all.
Analytical chemistry
Mehdi Tavancheh; Asadollah Beiraghi
Abstract
A simple, rapid, and sensitive spectrophotometric method for the determination of selenium (IV) based on the formation of a 1:2 complex with 4,5-diamino-o-xylene (DAX) as a new sensitive and selective chromogenic reagent is developed. The DAX reacts with selenium (IV) in the presence of citric acid to ...
Read More
A simple, rapid, and sensitive spectrophotometric method for the determination of selenium (IV) based on the formation of a 1:2 complex with 4,5-diamino-o-xylene (DAX) as a new sensitive and selective chromogenic reagent is developed. The DAX reacts with selenium (IV) in the presence of citric acid to form a complex in the pH range of 1.0 2.2. The experimental conditions for determining selenium including the influences of pH, reagent concentration and time were evaluated and optimized. Under the optimum experimental conditions, the molar absorptivity of the complex was 1.27×104 L/mol–1 cm–1 at 340 nm. Beer's law is obeyed in the range of 1≃12 µg/mL–1. The limits of detection and quantization were 0.948 µg mL-1 and 3.16 µg/mL-1 respectively. The interfering effect of some cations and anions was also studied. This method can be applied to the direct and easy determination of selenium species as organic, inorganic, Se(VI) and Se(IV) in a variety of real samples.
Analytical chemistry
Hamidu Usman; Blessing Oluchukwu; Faisal Bello; Muhammad Tijjani; Kyari Sanda; Halima Umar; Sule Ibrahim
Abstract
This study reports the phytochemical constituents and anti-diarrhoeal potentials of leafextracts of Corchorus olitorius Linn. (Malvaceae) and that of aerial part of Scoporia dulcis Linn. (Lantaginaceae) in rats. Samples were collected in December, 2016 from Nnewi-ichi, Nnewi, Anambra State and Mandara-Abdu, ...
Read More
This study reports the phytochemical constituents and anti-diarrhoeal potentials of leafextracts of Corchorus olitorius Linn. (Malvaceae) and that of aerial part of Scoporia dulcis Linn. (Lantaginaceae) in rats. Samples were collected in December, 2016 from Nnewi-ichi, Nnewi, Anambra State and Mandara-Abdu, Biu- Borno State, Nigeria, respectively. The phytochemical screening of the C. olitorius and the aerial part of S. dulcis extracts were conducted using standard methods; the results revealed the presence of cardiac glycosides, flavonoids, free and combined reducing sugar and tannins. Saponins was only found in S. dulcis. The diarrhoea was induced in rats by castor oil-induced method. The rats were grouped into 3 rats of 5 groups for each extract; groups I and II served as negative and positive control, while groups III, IV and V as treatment groups. The results showed a non-dose dependent but significant (p<0.05) effects with the lowest mean number of defecations at 6.67±1.70 and 10.33±0.94; and highest protections of 75.00% and 61.27% respectively at the same dose of 300 mg/kg bd. wt. for C. olitorius and S. dulcis. Comparatively, C. olitorius showed significantly (p<0.05) low severity of diarrhoea relative to S. dulcis. Thus, it showed reduction in the faecal output and protection of the rats from diarrhoea induced by castor oil. These observed results could explain their use as anti-diarrhoeal agents in African Traditional Medicine especially in Nigeria where the plants are used.
Analytical chemistry
Naglaa Mahmoud Mohamed; Yousry Moustafa Issa; Nabila Shehata Mohamed; Hussein Shaban Mohamed; Sayed Abdelkader Ahmed
Abstract
The evaluation of oxomemazine hydrochloride (OXCl) prepared in carbon paste electrodes is reported in detail. There are many practical techniques and experiments for electrode preparation one of them is mixing of the ion-pair with ion pairing agent. Prepared electrodes gave satisfactory data in ...
Read More
The evaluation of oxomemazine hydrochloride (OXCl) prepared in carbon paste electrodes is reported in detail. There are many practical techniques and experiments for electrode preparation one of them is mixing of the ion-pair with ion pairing agent. Prepared electrodes gave satisfactory data in ranging from (0.018 to 18.35) mg based on Nernstian cationic slopes, the used electrodes refer to the standard data obtained at (slope 58.7±2.1 mV decade-1) by using sodium tetraphenylborate (NaTPB) and rapid response time equal to 15 s and lifetime approximately equal to (4 weeks). The prepared electrodes can be counted as end point indicator electrode for potentiometric titration of oxomemazine Hydrochloride OXCl resulting in a high percentage of accuracy.
Analytical chemistry
Mahmood Payehghadr; Samaneh Adineh Salarvand; Farzaneh Nourifard; M. Kazem Rofouei; Niloufar Bahramipanah
Abstract
A new ligand, 1,5-bis( para methoxyphenyl)-3- ethyl-1,4-pantaazadiene has been synthesized by reaction of the 4-methoxyaniline (p-anisidine) with ethylamine. The mixture was stirred in an ice bath for 30 min. The structure of the synthesized compound resulted from the IR and 1HNMR and 13CNMR. Afterwards, ...
Read More
A new ligand, 1,5-bis( para methoxyphenyl)-3- ethyl-1,4-pantaazadiene has been synthesized by reaction of the 4-methoxyaniline (p-anisidine) with ethylamine. The mixture was stirred in an ice bath for 30 min. The structure of the synthesized compound resulted from the IR and 1HNMR and 13CNMR. Afterwards, a carbon paste electrode modified with this new ligand was developed for the silver determination at nanomolar level concentration. The electerochemical properties of this modified electrode was investigated by employing cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods in an acetate buffer solution (pH=4.8). The effect of pH, scan rate, percentage of modifier and buffer as supporting electrolyte on the electrode process were investigated. The oxidation peak of Ag+ was observed at about 0.4- 0.5 V. The resulting electrode demonstrated linear response across a 10-9 to 10-8 mol.L-1 of silver concentration range with a detection limit value of 1.61×10-10mol.L-1, on the basis of a signal to noise ratio of 3. Relative Standard deviation (RSD%) of the electrode performance was 2.41%. This MCPE, were showed high sensitivity and selectivity to Ag+ ions in aqueous samples.
Analytical chemistry
Hafsa A. Alemam; Abdounasser Omar; Magdi M. Gibali; Abdurrhman. A. Abdullaakarem; Farouq. A. Alastay; Ehabeddin. M. Elftisi; Abdulnabi Ali Abushita
Abstract
Tobacco products are known to contain some heavy metals that pose threats to smokers. In order to assess the role of smoking habits in increasing the plasma concentration of cadmium (Cd), chromium (Cr) and lead (Pb), a comparative study between male smokers and nonsmokers was carried out in Tripoli, ...
Read More
Tobacco products are known to contain some heavy metals that pose threats to smokers. In order to assess the role of smoking habits in increasing the plasma concentration of cadmium (Cd), chromium (Cr) and lead (Pb), a comparative study between male smokers and nonsmokers was carried out in Tripoli, Libya. Graphite furnace atomic absorption spectrometry (GFAAS) was used to determine the concentration of Cd, Cr and Pb in plasma blood of 25 male nonsmokers representing control group, and of 75 male smokers divided equally into three subgroups, which were: cigarette smokers group, waterpipe group and snuff inhalers group. According to 2-sample test, the means (or the medinas) of Cd, Cr and Pb plasma concentrations were significantly higher in smokers group compared to the nonsmokers group, and as the one-way analysis of Variance (ANOVA) test revealed, the means of Cd, Cr and Pb plasma concentrations were significantly higher in waterpipe group compared to the other two smokers’ groups. In conclusion, smoking increased the plasma concentration of Cd, Cr and Pb, and smoking waterpipe is considered to elevate the plasma concentration of those three metals more than the other two smoking habits, thus it is more dangerous on smokers’ lives.
Analytical chemistry
Mahmoud Abdelfatah Mohamed
Abstract
The current study aimed to develop and new, simple, accurate, economical and stability-indicating RP-HPLC for simultaneous estimation of Amlodipine Besylate, Valsartan and its related substances in their film-coated tablets dosage form. Chromatographic system was performed on the YMC ODS-A C18 (150 mm ...
Read More
The current study aimed to develop and new, simple, accurate, economical and stability-indicating RP-HPLC for simultaneous estimation of Amlodipine Besylate, Valsartan and its related substances in their film-coated tablets dosage form. Chromatographic system was performed on the YMC ODS-A C18 (150 mm × 4.6 mm, 5μm particle size) using a binary gradient elution consist of two solvent systems, solution (A) 0.02 monobasic sodium phosphate Adjust with phosphoric acid to a pH of 2.5. and solution (B) consisting of Solution A: Acetonitrile (45:55). at a flow rate of 1.0 mL/min, injection volume 10 µL, UV detection at 235 nm, column oven temperature 30 ºC and autosampler temperature 10 ºC. This method was validated according to ICH requirements for new methods, which include accuracy, precision, selectivity, robustness, ruggedness, LOD, LOQ, linearity and range. Linear relationships were obtained in the ranges of 10-300 µg/mL and 5-200 µg/mL with correlation coefficients of 0.9997 and 0.9998 for Amlodipine Besylate and Valsartan respectively. The forced degradation studies as acidity, alkalinity, oxidation, heat, thermal, humidity and photodegradation were performed according to ICH guidelines.
Analytical chemistry
Mohamed Nageeb Rashed; Allia Abd-Elmenaim Gad; Nada Magdy Fathy
Abstract
In this study low cost biochar adsorbent originated from camel bone was prepared by physically treatment, and examine the developed camel bone biochar for the removal of Cd2+ and Pb2+ from their solutions. The biochar adsorbent was characterized before and after development by XRD,SEM, FT-IR, and BET ...
Read More
In this study low cost biochar adsorbent originated from camel bone was prepared by physically treatment, and examine the developed camel bone biochar for the removal of Cd2+ and Pb2+ from their solutions. The biochar adsorbent was characterized before and after development by XRD,SEM, FT-IR, and BET surface The bone sample was pyrolyzed at temperature 500,600, 800, and 900 °C. Adsorption efficiency of Pb and Cd were optimized at different parameters (pH,pH z, contact time , initial metal concentration , adsorbent dosage and temperature. Adsorption kinetic, isotherms, and thermodynamic models have been performed to confirm the adsorption technique.The results revealed that the effective pyrolysis temperature for camel bone was 800oC that suitable for the high removal of Cd and Pb.The maximum adsorption removal percentage for Cd and Pb were 99.4 and 99.89 % , respectively at constant contact time 1 h, 1 g dose, pH 5, and 10 mg/L intial metal concentration. The kinetic results of cadmium and lead adsorption obeyed a pseudo-second-order model and fitted well with the Langmuir isotherm.
Analytical chemistry
Sangeetha Premkumar; Anandkumar Karunakaran; Vasanthi Murugesan; Jambulingam Munusamy; Ramesh Jayaprakash; Raja Murugesan
Abstract
A new, simple, accurate and sensitive UV ‐ Spectrophotometric absorbance correction method has been developed for simultaneous determination of Pyridoxine Hydrochloride and Doxylamine Succinate in bulk and in combined tablet dosage form using distilled water as a solvent. The wavelengths selected for ...
Read More
A new, simple, accurate and sensitive UV ‐ Spectrophotometric absorbance correction method has been developed for simultaneous determination of Pyridoxine Hydrochloride and Doxylamine Succinate in bulk and in combined tablet dosage form using distilled water as a solvent. The wavelengths selected for the analysis were 260 nm and 324 nm. Both Pyridoxine hydrochloride and Doxylamine Succinate were linear over the concentration range of 5 - 40 µg/ ml and 10 - 60 µg/ ml of Doxylamine Succinate and Pyridoxine hydrochloride, respectively. The percentage recovery was found to be in the range of 99.15 ‐ 100.71% for Pyridoxine Hydrochloride and 99.30 ‐ 101.99% for Doxylamine Succinate. The %RSD for recovery studies was found to be 0.5484 and 0.9071 for Pyridoxine hydrochloride and Doxylamine Succinate, respectively for. The low %RSD of recovery studies indicated that there is no interference due to excipients used in formulation. The amount of PYRI and DOXY was found to be 100.92% ± 0.6961 and 101.05% ± 0.7965. Optical characteristics like slope, intercept, molar absorptivity, correlation coefficient, LOD and LOQ were calculated. The developed method was validated statistically by recovery studies as per ICH guidelines. The % RSD value was found to be less than 2. Thus the proposed method was simple, precise, rapid and accurate and can be successfully applied for routine quality control analysis of simultaneous determination of Pyridoxine Hydrochloride and Doxylamine Succinate in bulk and in combined tablet dosage form.
Analytical chemistry
Mostafa Jafari
Abstract
A new method for estimation of adsorption properties of a solid phase microextraction fiber by artificial neural network (ANN) has been studied for the first time ever. An etched steel fiber which is simple prepared and durable was selected and adsorption of 12 analytes that were in four different chemical ...
Read More
A new method for estimation of adsorption properties of a solid phase microextraction fiber by artificial neural network (ANN) has been studied for the first time ever. An etched steel fiber which is simple prepared and durable was selected and adsorption of 12 analytes that were in four different chemical categories, was studied. 9 of them were selected as the training and 3 as the test. The amount of adsorptions were obtained through the direct extraction from aqueous and then GC analysis. The adsorption were analyzed by ANN. The results are quite satisfactory and the mean absolute percentage error of tests was 18.0 %. The method was simple, practical, straightforward, economical, and accurate. The method did not require many analytes.
Analytical chemistry
Adams Itodo; Raymond Wuana; Bulus Emmanuel Duwongs; Davoe Danbok Bwede
Abstract
Mining activities are one of the numerous ways by which man impacts on his environment. In this study, two non-destructive analytical techniques (XRF and XRD) were employed in the mineralogical characterization of Columbite-Tin ore and their contaminated soils. This investigates associated unnoticed ...
Read More
Mining activities are one of the numerous ways by which man impacts on his environment. In this study, two non-destructive analytical techniques (XRF and XRD) were employed in the mineralogical characterization of Columbite-Tin ore and their contaminated soils. This investigates associated unnoticed minerals as well as the impact of mining on vicinity farmland soils on the Yelwa-Mbar mining site, Nigeria. The chemical characterization of Columbite ore using electron dispersive XRF revealed that most of the Columbite mineral deposits in the Plateau mining sites contain Niobium mineral in various proportions and vary from deposit to deposit depending on the geochemical composition of the minerals that formed the parent rock. Tin content as determined by ED-XRF impart that the ore can be utilized directly in the furnace because of its high cassiterite content (85.43%). The percentage elemental composition of soil around the mining vicinity unveiled the presence of Radionuclides K-40, Rubidium and Thorium in the soil. This is of great concern. The XRD mineralogical investigation of Columbite shows the presence of associated braunite, cassiterite, ilmenite, quartz, and zircon while the phase pattern for Tin ore confirmed the availability of cassiterite, magnetite and litharge. Pollution status based on contamination factor and geo-accumulation indices gave both radionuclides and heavy metal concentrations that depicts moderate to extreme contaminations.
Analytical chemistry
Kingsley Ogemdi Iwuozor
Abstract
This research was aimed at the qualitative and quantitative determination of three anti-nutritional factors (Oxalate, Phytate, and Tannins) present in five wine samples produced in Nigeria. The determination of tannin was done using Folin-Denis Spectrophotometric method, the determination of oxalate ...
Read More
This research was aimed at the qualitative and quantitative determination of three anti-nutritional factors (Oxalate, Phytate, and Tannins) present in five wine samples produced in Nigeria. The determination of tannin was done using Folin-Denis Spectrophotometric method, the determination of oxalate was done through three processes namely; digestion, oxalate precipitatin and permanganate titration. From the result obtained, it was revealed that the five wine samples actually contained these anti-nutritional factors and these compounds were present in amounts that were not toxic to the human health. Ingestion of the wine samples over a long period of time could increase the anti-nutritional content and cause serious health challenges that could affect the liver and kidney. Therefore sensitization on the harms of prolonged intake of these wine samples should be a priority to the government. Government should also impose a strict law that will checkmate manufacturers of these drinks so as to make sure that these drinks are properly treated.
Analytical chemistry
Sakineh Alizadeh; Tayyebeh Madrakian; Morteza Bahram
Abstract
The present study aims to present a new convenient sensor for heavy metals, based on aggregation of citrate-capped- N, N' biphenyl hydrazine 1, 2 dicarbothioamide (PHCA) - modified- (AuNPs). This paper reports a procedure for sensitive and selective spectrophotometric methods for simultaneous determination ...
Read More
The present study aims to present a new convenient sensor for heavy metals, based on aggregation of citrate-capped- N, N' biphenyl hydrazine 1, 2 dicarbothioamide (PHCA) - modified- (AuNPs). This paper reports a procedure for sensitive and selective spectrophotometric methods for simultaneous determination of mercury (Hg22+) and cadmium (Cd2+). For this aim multivariate data including kinetic spectra of AuNPs were collected during aggregation process. The characterization of AuNPs was performed by transmission electron microscopy (TEM) and Infra-Red (IR) spectroscopy. Partial least square (PLS) regression as an efficient multivariate calibration method was employed to make a connection between the surface plasmon resonance (SPR) spectra of the generated AuNPs. The number of PLS latent variables was optimized by leave-one-out cross-validation utilizing prediction residual error sum of square (PRESS). The linear range was in the range of 3.33 × 10-5 - 3.33 × 10-6 mol L-1 and 2.0 × 10-5 - 1.0 × 10-6 mol L-1, the detection limit was 1.21×10-7 and 0.5 ×10-7 mol L-1 (n=5) for Hg22+and Cd2+, respectively. This method used successfully for simultaneous determination of Hg22+ and Cd2+ in West Azerbaijan regional waters namely Zarineh / Simineh rivers and Urmia Lake.
Analytical chemistry
Abdel-Moneum M. Ahmed; Alaa E. Ali; Ahmed H. Ghazy
Abstract
In this study, the adsorption potential of activated carbon olive stone for removal of Ni(II) ions from wastewater has been investigated. The study involves batch type experiments to investigate the effect of initial concentration, adsorbent dose, agitation speed, contact time, temperature and pH of ...
Read More
In this study, the adsorption potential of activated carbon olive stone for removal of Ni(II) ions from wastewater has been investigated. The study involves batch type experiments to investigate the effect of initial concentration, adsorbent dose, agitation speed, contact time, temperature and pH of solution on adsorption process and the optimum conditions were evaluated. The adsorption process has fit pseudo-second order kinetic models. Langmuir and Freundlichadsorption isotherm models were applied to analyze adsorption data and both were found to be applicable to this adsorption process. Thermodynamic parameters, e.g., ΔGº, ΔSº and ΔHº of the on-going adsorption process have also been calculated and the sorption process was found to be endothermic. Finally, it can be seen that activated carbon olive stone was found to be more effective for the removal of Ni(II) from waste water than any adsorbent was used.
Analytical chemistry
Kingsley Ogemdi Iwuozor; Emuobosa Ejiroghene Gold
Abstract
This work examined some physicochemical parameters of effluents from a Brewery Industry in Imo state. This company discharged effluents in non-compliance with the Nigerian National Regulations as confirmed from the Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Electrical Conductivity ...
Read More
This work examined some physicochemical parameters of effluents from a Brewery Industry in Imo state. This company discharged effluents in non-compliance with the Nigerian National Regulations as confirmed from the Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Electrical Conductivity (EC), Nitrogen, and Turbidity results. The heavy metals have concentrations that were within WHO/FEPA limits. These confirmed results posed health risks to several rural communities which rely on the receiving water bodies as their primary source of domestic water. There is need for the intervention of appropriate regulatory agencies to ensure production of high quality treated final effluents. This scenario is typical of most industries in developing nations where enforcement of environmental regulations are deficient. To avoid pollution, regulatory authorities should closely monitor compliance by industries.
Analytical chemistry
Mohamed Said Abdel Aal; Abdel Monem Mohamed Ahmed; Hanaa Hammam Abdel Rahman; Sherif Hussein Kandil
Abstract
We developed some Ultrafiltration (UF) membranes based on polysulfone (PSF) and poly acrylic acid (PAA) mixture. The Ultrafiltration membraneswere prepared by the phase inversion technique using Dimethylformamide (DMF) as a solvent. Immobilization of PAA in PSF matrix was confirmed by Fourier ...
Read More
We developed some Ultrafiltration (UF) membranes based on polysulfone (PSF) and poly acrylic acid (PAA) mixture. The Ultrafiltration membraneswere prepared by the phase inversion technique using Dimethylformamide (DMF) as a solvent. Immobilization of PAA in PSF matrix was confirmed by Fourier transform infrared spectroscopy (FTIR). The membranes have an asymmetric structure, as revealed by scanning electron microscopy (SEM). Natural water from Mahmoudia canal (a subdivision of the Nile River) is used as feed water. The permeate flux reached 120.0 l/m2.hr. The hydrophilicity measured by contact angle was enhanced by the addition of PAA to reach 66.00. The prepared membranes showed good tensile strength that reached 7.2 MPa. Turbidity rejection and dissolved organic carbon (DOC) rejection reached 98.4% and 65 %, respectively. These performances obtained at ambient operating conditions, make the fabricated membranes attractive for canal water treatment.
Analytical chemistry
Mahtab Baghban; Alireza Rezaian; Elahe Hashemi
Abstract
An efficient sample extraction using solid-phase extraction coupled with liquid-chromatography was studied for the analyses of three different types and chemical group pesticides from drinking water. The extraction was performed using a Waters Sep-Pak C-18 cartridge. A validation of the method was performed. ...
Read More
An efficient sample extraction using solid-phase extraction coupled with liquid-chromatography was studied for the analyses of three different types and chemical group pesticides from drinking water. The extraction was performed using a Waters Sep-Pak C-18 cartridge. A validation of the method was performed. Linearity (0.005-1000, 0.01-1000, 4-1000, 10.5-1000 and 9.48-1000 µg.L-1 for Simazine, Atrazine, Isoproturon, Metolachlor and Chlorotoluron respectively range), within-day precisions ranged from 4.8 to 6.7% and the between day precisions ranged of 7.8-13.3 % based on the peak areas for five replicates, limits of detection (0.001-2.846 µg.L-1) were calculated. The preconcentration factors (PFs) were obtained under the optimum conditions (15.04-22.53). The information obtained from the method validation has been used to estimate for the determination of pesticides at trace levels in water samples which collected from water treatment plants of Tehran, the capital of Iran.
Analytical chemistry
Javad Ghodsi; Amir Abbas Rafati; Yalda Shoja
Abstract
A new and easy to fabricate voltammetric biosensor for acetaminophen determination was developed based on horseradish peroxidase (HRP) trapped between silica sol-gel film and multi-walled carbon nanotubes on glassy carbon electrode. Acetaminophen determinations were carried out in presence of H2O2 as ...
Read More
A new and easy to fabricate voltammetric biosensor for acetaminophen determination was developed based on horseradish peroxidase (HRP) trapped between silica sol-gel film and multi-walled carbon nanotubes on glassy carbon electrode. Acetaminophen determinations were carried out in presence of H2O2 as enzyme activator. The modified electrode showed excellent electrocatalytic activity and rapid response to acetaminophen in the presence of H2O2 as enzyme activator. Various parameters influencing the biosensor performance such as amount of enzyme, H2O2 concentration, potential scan rate and pH have been investigated. Under the optimal conditions, a wide linear range of 1.85×10−6 to 2.7×10−3 M for acetaminophen determination was obtained. Limit of detection was calculated about 18 nM and sensitivity was about 220 nA/µM. Furthermore, the proposed biosensor was successfully examined for simultaneous determination of acetaminophen with uric acid (UA) and folic acid (FA) as prevalent interferes. The proposed biosensor showed satisfactory stability for 3 weeks and applicability of developed biosensor was confirmed with accurately evaluation of acetaminophen in real samples such as urine and tablet.
