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This systematic review followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. The primary aim of this research was to identify risks and protective factors for the mental health of forced migrants. The secondary aim was to suggest an alternative, more comprehensive approach in social work that surpasses usual diagnoses and intrinsically contradicts the medicalization of mental health issues of forced migrants. The search was conducted between January 2015 and January 2021. As a result, 29 studies met inclusion criteria. Medicalizing mental health issues by relying solely on the effectiveness of medicine was a controversial risk factor that negatively affected daily life activities of refugees and reduced their willingness for seeking professional mental health services. Empowering vulnerable minorities by giving them back their power and agency to be able to speak for themselves and raise voices of trauma and recovery was the missing protective factor for a sustainable mental health practice. The benefits of group-based interventions were highlighted in which communities and individuals address mental health issues as well as isolation through building collective identities and support networks. Information and communication technologies (ICTs) can add more strength to any kind of mental health interventions. Finally, the benefits of applying an ecological perspective for the study of the mental health of refugees, and its implications for a sustainable intercultural practice, were discussed. Social workers in this model are the representatives of at-risk groups, and thus require more agency and creativity in reflecting client’s concrete needs.

The solubility of hydrogen sulfide (H2S) in N-methylimidazole (NMI) and gamma-butyrolactone (GBL) were experimentally measured. Gas concentrations were systematically measured by isochoric saturation method at temperatures from (303.15 to 353.15) K and pressure from vapour pressure of solvent up to about 1.2 MPa, in all experiments mole fraction of dissolved gas has been measured with uncertainty order of 10−3. In order to construct a GA-artificial neural network (ANN)-based model, the H2S solubility, molality and total pressure were selected for the output. The precision of the GA is compared with experimental data and also with thermodynamic modelling approach in which Peng-Robinson-Stryjek-Vera (PRSV) cubic equation of state with Panagiotopoulos-Reid combining rule has been chosen for this purpose.

Wastewater discharge is considered to be a significant point source of microplastic (MPs) release into the marine environment. This study is the first attempt to quantify MPs released from the wastewater outfall from Bandar Abbas City into the Persian Gulf. Two wastewater discharge stations at Gursuzan and Suru were sampled. MPs were isolated by an oxidative procedure and subsequent density separation using ZnCl2 solution. The average MP concentration in wastewater and sludge were 70.66 (±14.12, SD) MP.35 L−1 and 6070 (±807.25) MPs.kg−1, respectively at Confidence Level (CL) (95.0%). The most commonly recovered polymers were polyethylene (PE) and polypropylene (PP) in all size classes. Our findings provides a baseline of MP concentration in wastewater streams and slurry that is discharged from the Bandar Abbas wastewater treatment facility into the Persian Gulf. This highlights the need to undertake more studies at water treatment plants in the region for a realistic assessment of MP discharge into the Persian Gulf.

In this paper, the boundary layer flow of a Powell–Eyring non-Newtonian fluid over a stretching sheet is considered which is lucrative in the production of many beneficial materials in the industry. Rational Gegenbauer (RG) functions are used to find the better solution comparing to other current works. The drawback of nonlinearity is met using a linearization method, namely, the quasi-linearization method (QLM). As comping on a semi-infinite domain, an approximation is considered to satisfy the infinity condition using the algebraic mapping of $$\frac{\xi -L}{\xi +L}$$ , where L is a positive arbitrary numerical parameter and a suitable value is calculated for it. Using the QLM, the equation is converted into a sequence of linear ordinary differential equations (ODE); then, these ODEs are solved using the RG collocation method. Finally, the numerical results are presented and the proposed method is compared with the state-of-the-art methods.

The solubility of carbonyl sulfide (COS) in two low vapor pressure organic solvents, namely, sulfolane (SFL) and γ-butyrolactone (GBL), was measured by experimental trial. The gas solubility was determined by using an isochoric saturation method under a static situation at temperatures from 303.15 to 353.15 K and pressures from the vapor pressure of solvent up to about 1.2 MPa. The absorption data were correlated by using the Peng–Robinson–Stryjek–Vera (PRSV) cubic equation of state (EoS) as the φ–φ approach and the Krichevsky–Ilinskaya (KI) model with a combination of the PRSV EoS as the γ–φ approach. Using the solubility data, Henry’s law constant, Gibbs free energy, enthalpy, entropy, and gas molar volume at infinitely diluted solutions were calculated and interpreted.

A simple and totally organic-free (green) method, viz. headspace water-based liquid-phase microextraction combined with high-performance liquid chromatography-ultraviolet detection has been successfully developed for analysis of formic acid and acetic acid in environmental water samples. A microdrop of an aqueous solution of sodium hydroxide was suspended from the tip of a microsyringe needle over the headspace of the stirred sample solution containing the analytes at pH 1.0 for a given time. The microdrop was then retracted into the microsyringe, diluted with HPLC mobile phase, and injected to HPLC. Optimum efficiency has been achieved for: 3.0 µL NaOH microdrop (0.1 mol L−1) exposed for 15 min over the headspace of an aqueous sample of 6.5 mL at 55 °C, containing 15% w/v of Na2SO4, adjusted to pH = 1.0 and stirred at 750 rpm. Under these conditions, enrichment factors of 162 and 187, limits of detection of 0.3 and 0.1 µg L−1 (S/N = 3) with dynamic linear ranges of 1–500 and 0.5–500 µg L−1 were o...

A simple and efficient ionic liquid-based ultrasound-assisted in-situ solvent formation microextraction (IL-UA-ISFME) in combination with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) has been gainfully developed for the trace determination of four phthalate esters (PEs) in environmental water samples. In this method, a hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was created by addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to sample solution constituting an ion-pairing agent (NaPF6). The analytes were extracted inside the ionic liquid phase while the microextraction solvent was dispersed through the sample by utilizing ultrasonic radiation. The sample was then centrifuged and extracting phase retracted into the microsyringe, diluted with acetonitrile, and injected to HPLC. At first, vigorous parameters controlling the performance of the microextraction process were considered and optimized. The limit of detections (LOD, S/N = 3) were in the range of 0.22-0.33 µg L-1 while the RSD% values were below than 6.1% (n = 5). A good linearity (0.996 ≥ r2 ≥ 0.992) and a broad linear over the concentration range from 1.0 to 500 µg L-1 were achieved. At last, the method was applied for the preconcentration and sensitive determination of the PEs in several environmental water samples. The accuracy of the method in the real samples was examined by the relative recovery experiments with results ranging from 90-107%, which approved that intricate matrixes had approximately slight effect on the developed procedure.

A novel and efficient hollow fiber-based method, viz. magnetic solvent bar liquid-phase microextraction (MSB-LPME) combined with gas chromatography-flame ionization detection (GC-FID) was successfully developed for the trace determination of selected polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. The target analytes were extracted from sample solution to the organic solvent immobilized in a fiber. After extraction, the analyte-adsorbed magnetic solvent bar could be readily isolated from the sample solution by a magnet which could greatly simplify the operation and also decline the total pretreatment time. The bar was first eluted with methanol, evaporated to dryness while the residue was dissolved in toluene and finally injected into GC-FID. Begin with, effective parameters controlling the performance of the microextraction were evaluated and optimized. The values of the detection limit of the method were in the range of 0.05-0.08 µg L-1 and the RSD% values for the analysis of 10.0 µg L-1 of the analytes was below than 5.8% (n= 6). A good linearity (0.998 ≥ r2 ≥ 0.994) and a broad linear range (0.1-200 µg L-1) were obtained. The method was eventually utilized for the preconcentration and determination of the PAHs in environmental water samples and satisfactory results were obtained.

In this study, heavy metals pollutions in waters, soils and vegetables were investigated from farms, near oil refinery in south of Tehran city, Iran (Shahre Ray). The most important heavy metals in Iranian oil are vanadium, cobalt, nickel, arsenic and mercury (V, Co, Ni, As, Hg). In this region, the concentration of heavy metals in soils, well waters and leafy edible vegetables were evaluated in ten different points of farms. Geographic information systems (GIS) were used to estimate the levels of heavy metals concentration at unmeasured locations. After sample preparation, concentrations of heavy metals in vegetables, soils and waters were determined by atomic absorption spectrometry (AAS). Five different leafy edible vegetables from farms, i.e., Persian leek, dill, parsley, spinach and radish were sampled in spring, summer and autumn 2012. In vegetables and well water samples, the concentrations of V, Ni and Co were above the permissible limit of heavy metals as compared to WHO guidelines and the concentrations of these metals in agricultural soils were found to be lower in accordance to soil references. The industrial waste waters had high concentration of heavy metals in this area. In consequence, the results of this study indicate that industrial waste water can cause pollution in well waters and edible vegetables. So, this region is not suitable for cultivation and growing vegetables.

The solubility of hydrogen sulfide in N-methylacetamide and N,N-dimethylacetamide were experimentally measured. Gas concentrations were systematically measured by the isochoric saturation method at temperatures from (303.15 to 363.15) K and pressures from the vapor pressure of solvent up to about 2.2 MPa. Results show that H2S solubility in N,N-dimethylacetamide is more than that in N-methylacetamide. The experimental data were correlated using (1) the Krichevsky–Ilinskaya equation and (2) a generic Redlich–Kwong (RK) cubic equation of state. Using the solubility data, the partial molar thermodynamic properties of solution such as Gibbs free energy, enthalpy, and entropy at infinitely diluted solution, and also the enthalpies of absorption of loaded solutions were calculated using the Gibbs–Helmholtz equation.

Nanoliposomes are extensively used as ideal vehicles in drug delivery systems due to their unique biocompatibility and biodegradability properties. They can be used as sustained release and target selective conveyances to deliver the encapsulated drugs at specific cells or tissues by improving their efficacy along with reducing the side effects. As an analytical perspective, the determination of various lipid components in the final formulation is one of the practical issues while the agents are applied in an industrial-scale. Herein, the maximum ultra violet (UV) absorbances for the most of the lipids are within 200-210 nm that cause significant cut-off conflicts with the general solvents or additives of high-performance liquid chromatography (HPLC) during its method development procedure. In this study, a simple, accurate and cost-effective isocratic HPLC-UV method has been successfully developed for the simultaneous determination of α-(3-O-cholesteryloxy)-δ-(N-ethylmorpholine)-succineamide (MoChol), cholesteryl-hemisuccinate (Chems) and Cholesterol in nanoliposomes drug carriers containing an active pharmaceutical ingredient (anti-BCL-2 DNA oligonucleotide). The isocratic mobile phase consisted of ethanol/acetonitrile/water including trifluoroacetic acid (60/30/10 with 0.1% v/v, respectively) at a flow rate of 1.0 mL min-1 was run through a commercial reverse-phase C18 analytical column while UV detector was set at 202 nm. To confirm the applicability, a full validation of the proposed method was performed according to the International Council for Harmonization (ICH) guidelines.

The solubility of hydrogen sulfide and carbondioxide in dimethylsulfoxide and dimethylformamide were experimentally measured. Gas concentrations were systematically measured by isochoric saturation method at temperatures from 303.15 to 353.15 K and pressure from vapor pressure of solvent up to about 2.0 MPa. Results show that H2S dissolves more than CO2 in both solvents, and that chemical dissolution has significant role in H2S solubility in dimethylsulfoxide. The experimental data were correlated by using: (1) a model comprised of the extended Henry's law and Pitzer's virial expansion for the excess Gibbs energy, and (2) a generic Redlich–Kwong (RK) cubic equation of state.

A new and practical sample enrichment method termed ionic liquid-based ultrasound-assisted in situ solvent formation microextraction (IL-UA-ISFME) was combined with electrothermal atomic absorption spectrometry (ETAAS) for preconcentration and trace determination of vanadium in real samples. In this sample enrichment methodology, a hydrophilic ionic liquid (IL) ([Hmim][BF4]) was added to the aqueous media containing an ion-exchange reagent (NaPF6), in order to obtain a hydrophobic IL ([Hmim][PF6]) as the microextraction solvent. The hydrophobic extraction solvent formed under these conditions was completely dispersed into the sample solution using ultrasonic radiation. Vanadium was complexed with N-benzoyl-N-phenylhydroxylamine (BPHA), and extracted into the IL phase during the dispersion of the hydrophobic IL. Main variables affecting the recommended method was studied in details and optimized. Under the optimum conditions, the combined methodology provided a linear dynamic range of 15–2,500 ng l−1, a limit of detection (LOD) of 4.7 ng l−1 and a relative standard deviation (RSD) of 4.0 %. The accuracy and validity of the method was checked by analyzing a certified standard reference material of water (SRM-1643e). Finally, the developed method was utilized for quantitation of vanadium in real water and milk samples.

In this paper, we introduce the notions of neutrosophic deductive filter, Boolean neutrosophic deductive filter (BNDF) and implicative neutrosophic deductive filter (INDF) on BL-algebras as generalizations of the fuzzy corresponding versions. We also investigate some properties of these filters and drive some characterizations of them. The relation between BNDF and INDF is investigated and it is proved that every BNDF is an INDF, but the converse is true when certain condition is satisfied. Furthermore, we construct a quotient structure related to the neutrosophic deductive filter and prove certain isomorphism theorems.

Natural gas (NG) is one of the widely used domestic fuels in most of the countries, and because of economical and environmental advantages, its consumption is continuously increasing. As a result, complex piping systems are being installed to transport and distribute the gas for end users. Pipelines carrying NG are a significant source of hazard for their adjacent society. The risk of this hazard could be high especially in distribution network and urban areas where the population density is high. The common causes of accident in NG distribution network are: third party interference, corrosion, fatigue, stress corrosion cracking (SCC), etc. Accident in network leads to leakage and release of NG and consequent injuries and losses. To prevent these adverse outcomes, the risks should be identified and assessed carefully, so that they can be controlled and managed properly. In this work, risk assessment of NG distribution pipelines was surveyed and quantitative methods were recommended for assessing the individual and societal risks of distribution network.

Purpose – The purpose of this paper is to describe the behavior of 2-mercaptobenzothiazole (MBT) on the corrosion of 316 stainless steel (SS) in acidic media and the mechanism of its action. Design/methodology/approach – The inhibitive effect of MBT towards the corrosion of 316 SS in acid solution is studied by means of weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. The effect of inhibitor concentration and temperature against inhibitor action is investigated. Adsorption isotherm and adsorption mechanism are also discussed. Findings – MBT acts as inhibitor for this type of steel in acidic medium. This compound is mixed-type inhibitor and inhibition efficiency increased with increasing inhibitor concentration. MBT retards the rate of both anodic and cathodic corrosion reactions by adsorbing and forming a layer on the steel surface and the adsorption obeys Temkin adsorption isotherms. The inhibition efficiency is temperature dependence in the range from 25 to 65°C and some thermodynamic parameters were calculated and analyzed. Originality/value – The results shown in this paper are an insight to the understanding of the corrosion resistance and electrochemical behavior of 316 SS in the presence of MBT for future industrial applications and development. It is the first time that corrosion inhibition effects of MBT on 316 SS have been evaluated.

In this paper, we define $$n$$ -fold EIMTL and $$n$$ -fold IMTL-filters of MTL-algebras and investigate some relations between these filters and $$n$$ -fold (positive) implicative filters, $$n$$ -fold fantastic filters and $$n$$ -fold obstinate filters of MTL-algebras. Also, we investigate under what conditions the $$n$$ -fold implicative MTL-algebra is the $$n$$ -fold positive implicative MTL-algebra.

Article history: Received January 26, 2013 Received in Revised form May 10, 2013 Accepted 28 May 2013 Available online 2 June 2013 In this study, for the first time we report a highly selective and sensitive lutetium ions chemical optical sensor based on immobilization of a asymmetrically S–N Schiff’s base, namely N(thien-2-ylmethylene)pyridine-2,6-diamine (TPD) on a triacetylcellulose membrane. This optode exhibits a linear range of 5.0 ×10 –1.0 ×10 M of the Lu(III) ion concentration with a detection limit of 9.3 ×10 M at a wavelength of 336 nm. The influence of responsible factors for improving sensitivity of the sensor was studied and identified. Response time of the newly designed optode was within 20-30 s depending on the Lu(III) ion concentration. Response of the optical sensor is independent of the pH of the solution in the range of 3.0–9.0. It manifests advantages of fast response time, low detection limit and most significantly, very good selectivity with respect to a number of lanthanide ions. The sensor can readily be regenerated with thiourea solutions and its response was reversible and reproducible. This optode was applied to the determination of Lu(III) in aqueous and CRM samples. © 2013 Growing Science Ltd. All rights reserved.

This study was designed to examine the chemical composition of essential oil and in vitro antioxidant and antimicrobial activity of the essential oil and methanol extracts of Eucalyptus largiflorens F. Muell. The chemical composition of the hydrodistilled essential oil of the leaves of E. largiflorens was analyzed by gas chromatography and gas chromatography/mass spectrometry. The main constituents of the oil were found to be 1,8-cineole (23.1%), cryptone (15.1%), 4-allyloxyimino-2-carene (11.2%), and 4-terpineol (9.6%). The essential oil showed strong antibacterial activity against the studied microorganisms, except for P. aeruginosa, while polar subfraction of methanol extract had moderate antimicrobial activity and the nonpolar subfraction of methanol extract did not show any antimicrobial activity. In contrast, the extract showed better activity than the essential oil in antioxidant activity assays employed, e.g., in a 2,2-diphenyl-1-picryl-hydrazyl system. Also, the polar subfraction of methanol extr...

A robust extraction method against the variations of sample ionic strength viz. ionic liquid-based ultrasound-assisted in situ solvent formation microextraction (IL-UA-ISFME) was coupled for the first time with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), and successfully used as a more sustainable approach for the determination of meloxicam (MEL) in human plasma. Herein, a hydrophobic IL (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by adding a hydrophilic IL (1-butyl-3-methylimidazolium tetrafluoroborate) to aqueous sample solution containing an ion-exchange reagent (sodium hexafluorophosphate). The target analyte was transferred into the IL medium while the extraction solvent was completely dispersed into the sample using ultrasonic irradiation and then, the settled enriched phase was injected to HPLC. Firstly, main factors affecting the microextraction performance were evaluated and optimized. The linearity was in the range of 5-1,500 ng mL-1 with regression coefficient corresponding to 0.997. Limits of detection (LOD; signal-to-noise ratio (S/N) = 3) and quantification (LOQ, S/N = 10) were 1 and 5 ng mL-1, respectively. An acceptable recovery range of 82.1-93.6% and satisfactory intra-assay (3.6-4.8%, n = 6) and inter-assay (3.3-5.1%, n = 9) precision as well as remarkable sample clean up exhibited good efficiency of the method. The freeze-thaw stability study was performed for samples and standard solutions. To study the applicability of the proposed method, it was employed for the determination of MEL in human plasma after oral administration of the drug and some pharmacokinetic data were achieved. The technique proved to be accurate and reliable for the screening intentions.

An efficient analytical method called ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography was developed for the determination of atenolol in human plasma. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by the addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to a sample solution containing an ion-pairing agent during microextraction. The analyte was extracted into the ionic liquid phase while the microextraction solvent was dispersed throughout the sample by utilizing ultrasound. The sample was then centrifuged, and the extracting phase retracted into the microsyringe and injected to liquid chromatography. After optimization, the calibration curve showed linearity in the range of 2-750 ng/mL with the regression coefficient corresponding to 0.998. The limits of detection (S/N = 3) and quantification (S/N = 10) were 0.5 and 2 ng/mL, respectively. A reasonable relative recovery range of 90-96.7% and satisfactory intra-assay (4.8-5.1%, n = 6) and interassay (5.0-5.6%, n = 9) precision along with a substantial sample clean-up demonstrated good performance of the procedure. It was applied for the determination of atenolol in human plasma after oral administration and some pharmacokinetic data were obtained.

Solid-phase extraction (SPE) in tandem with dispersive liquid–liquid microextraction (DLLME) has been developed for the determination of mononitrotoluenes (MNTs) in several aquatic samples using gas chromatography-flame ionization (GC-FID) detection system. In the hyphenated SPE-DLLME, initially MNTs were extracted from a large volume of aqueous samples (100 mL) into a 500-mg octadecyl silane (C18) sorbent. After the elution of analytes from the sorbent with acetonitrile, the obtained solution was put under the DLLME procedure, so that the extra preconcentration factors could be achieved. The parameters influencing the extraction efficiency such as breakthrough volume, type and volume of the elution solvent (disperser solvent) and extracting solvent, as well as the salt addition, were studied and optimized. The calibration curves were linear in the range of 0.5–500 mg/L and the limit of detection for all analytes was found to be 0.2 mg/L. The relative standard deviations (for 0.75 mg/L of MNTs) without internal standard varied from 2.0 to 6.4% (n 5 5). The relative recoveries of the well, river and sea water samples, spiked at the concentration level of 0.75 mg/L of the analytes, were in the range of 85–118%.

The applicability of hollow fiber liquid-phase microextraction (HF-LPME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was evaluated for the extraction and determination of tamoxifen (TAM) in biological fluids including human urine and plasma. The drug was extracted from a 15 mL aqueous sample (source phase; SP) into an organic phase impregnated in the pores of the hollow fiber (membrane phase; MP) followed by the back-extraction into a second aqueous solution (receiving phase; RP) located in the lumen of the hollow fiber. The effects of several factors such as the nature of organic solvent, compositions of SP and RP solutions, extraction time, ionic strength and stirring rate on the extraction efficiency were examined and optimized. An enrichment factor of 360 along with substantial sample clean up was obtained under the optimized conditions. The calibration curve showed linearity in the range of 1 - 500 ng?mL–1 and the limit of detection was found to be 0.5 ng?mL–1 in aqueous medium. A reasonable relative recovery (≥89%) and satisfactory intra-assay (3.7% - 4.2%, n = 3) and inter-assay (7.5% - 7.8%, n = 3) precision illustrated good performance of the analytical procedure in spiked human urine and plasma samples.

A simple and efficient method, ionic liquid-based dispersive liquid-liquid microextraction combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), has been applied for the extraction and determination of some antioxidants (Irganox 1010, Irganox 1076 and Irgafos 168) in water samples. The microextraction efficiency factors were investigated and optimized: 1-hexyl-3-methylimidazolium hexafluorophosphate [C 6 MIM][PF 6 ] (0.06 g) as extracting solvent, methanol (0.5 mL) as disperser solvent without salt addition. Under the selected conditions, enrichment factors up to 48-fold, limits of detection (LODs) of 5.0-10.0 ng/mL and dynamic linear ranges of 25-1500 ng/mL were obtained. A reasonable repeatability (RSD≤ 11.8%, n = 5) with satisfactory linearity (r 2 ≥ 0.9954) of the results illustrated a good performance of the presented method. The accuracy of the method was tested by the relative recovery experiments on spiked samples, with results ranging from 85 to 118%. Finally, the method was successfully applied for determination of the analytes in several real water samples.

Dispersive liquid-liquid microextraction (DLLME), coupled with gas chromatography-flame ionization detection (GC-FID), has been successfully used for the extraction and determination of valproic acid (VPA) in pharmaceutical preparations. In the developed method, an appropriate mixture of extracting and disperser solvents was rapidly injected into an aqueous sample. Having formed a cloudy solution, the mixture was centrifuged and then the extracting solvent was sedimented at the bottom of a conical test tube. The extract was then injected into a GC system directly, without any further pretreatment. Initially, microextraction efficiency factors were optimized and the optimum experimental conditions found were as follows: tetrachloroethylene (9.0 µL) as extracting solvent; acetone (1.0 mL) as disperser solvent; 5 mL acidic aqueous sample (pH 1) without salt addition. Under the selected conditions, the calibration curve showed linearity in the range of 0.1–5.0 mg/L with regression coefficient corresponding to 0.9998. The limit of detection was found to be 0.05 mg/L. Finally, the method was applied for the determination of VPA in two different pharmaceutical preparations. A reasonable intra-assay (3.9–10.8%, n = 3) and inter-assay (5.6–11.4%, n = 3) precision illustrated the good performance of the analytical procedure. The protocol proved to be rapid and cost-effective for screening purposes. Copyright © 2010 John Wiley & Sons, Ltd.

A simple, efficient and virtually solventless headspace liquid-phase microextraction (HS-LPME) technique, combined with gas chromatography-mass spectrometry (GC-MS), was developed for the analysis of sorbic acid (SA) and benzoic acid (BA) in soft drinks and environmental water samples. A microdrop of organic solvent was suspended from the tip of a microsyringe needle over the headspace of the stirred sample solution, containing the analytes for a desired time. The microdrop was then retracted into the microsyringe and directly injected into the GC-MS, without any further pretreatment. Initially, microextraction efficiency factors were optimized, and the optimum experimental conditions found were as follows: 2.5 microL toluene microdrop exposed for 20 min over the headspace of a 6.5 mL aqueous sample (45 degrees C), containing 3 M of NaCl with pH of 1.5 and stirred at 1000 rpm. Under the optimized extraction conditions, preconcentration factors of 154 and 198, limits of detection of 0.3 and 0.1 microg L(-1) (S/N=3) with dynamic linear ranges of 1-500 and 0.5-500 microg L(-1), were obtained for SA and BA respectively. A good repeatability (RSD10.3%, n=8) and satisfactory linearity (r(2)or= 0.99) of results were achieved. The accuracy of the method was tested by the relative recovery experiments on spiked samples, with results ranging from 90 to 113%. The method proved to be rapid and cost-effective and is a green procedure for screening purposes.

A simple and efficient liquid-phase microextraction (LPME) in conjunction with gas chromatography-electron capture detector (GC-ECD) has been developed for extraction and determination of 11 organochlorine pesticides (OCPs) from water samples. In this technique a microdrop of 1-dodecanol containing pentachloronitrobenzene (internal standard) is delivered to the surface of an aqueous sample while being agitated by a stirring bar in the bulk of solution. Following completion of extraction, the sample vial was cooled by putting it into an ice bath for 5 min. Finally 2 μL of the drop was injected into the GC for analysis. Factors relevant to the extraction efficiency were studied and optimized. Under the optimized extraction conditions (extraction solvent: 1-dodecanol; extraction temperature: 65 °C; sodium chloride concentration: 0.25 M; microdrop and sample volumes: 8 μL and 20 mL respectively; the stirring rate: 750 rpm and the extraction time: 30 min), figures of merit of the proposed method were evaluated. The detection limits of the method were in the range of 7–19 ng L −1 and the RSD% for analysis of 2 μg L −1 of OCPs was below 7.2% ( n = 5). A good linearity ( r 2 ≥ 0.993) and a relatively broad dynamic linear range (25–2000 ng L −1 ) were obtained. After 30 min of extraction, preconcentration factors were in the range of 708–1337 for different organochlorine pesticides and the relative errors ranged from −10.1 to 10.9%. Finally the proposed method was successfully utilized for preconcentration and determination of OCPs in different real samples.

Oil and gas well drilling activities are associated with numerous hazards which have the potential to cause injury or harm for people, property and the environment. These hazards are also a threat for the reputation of drilling companies. To prevent accidents and undesired events in drilling operations it is essential to identify, evaluate, assess and control the attendant risks. In this work, a structured methodology is proposed for risk assessment of drilling activities. A case study is performed to identify, analyze and assess the risks arising from human factors in one of the on shore drilling sites in southern Iran. A total of 17 major hazards were identified and analyzed using the proposed methodology. The results showed that the residual risks of 100% of these hazards were in the acceptable or transitional zone, and their levels were expected to be lowered further by proper controls. This structured methodology may also be used in other drilling sites and companies for assessing the risks.

A simple and sensitive method based on a modified hollow-fiber liquid-phase microextraction followed by gas chromatography–mass spectrometry has been successfully developed for the extraction and simultaneous derivatization of some nitrophenols (NPs) in soil and rain samples. Microwave-assisted solvent extraction was used for the extraction of NPs from the soil, while the rain sample was directly applied to the previously mentioned method. Briefly, in this method, the analytes were extracted from aqueous samples into a thin layer of organic solvent (dodecane + 10 % tri-n-octylphosphine oxide) sustained in the pores of a porous hollow fiber. Then, they were back-extracted using a small volume of organic acceptor solution (25 μl; 10 mg/L N-methyl-N-(trimethylsilyl)trifluoroacetamide, as derivatization reagent, in acetonitrile) that was located inside the lumen of the hollow fiber. Under the optimized extraction conditions, enrichment factors of 255 to 280 and limits of detection of 0.1 to 0.2 μg/L (S/N = 3) with dynamic linear ranges of 1–100 μg/L were obtained for the analytes. The accuracy of the approach was tested by the relative recovery experiments on spiked samples, with results ranging from 93 to 113 %. The method was shown to be rapid, cost-effective, and potentially interesting for screening purposes.

A novel and efficient speciation method based on the nano-structured lead dioxide as stationary phase of head space solid phase microextraction combined with gas chromatography mass spectrometry (GC-MS) was developed for the determination of volatile organoselenium compounds (dimethylselenide (DMSe) and dimethyldiselenide (DMDSe)) in different biological and environmental samples. PbO(2) particles with a diameter in the range of 50-70 nm have been grown on platinum wire via elechtrochemical deposition. The effect of different variables on the extraction efficiency was studied simultaneously using an experimental design. The variables of interest in the HS-SPME were condition of coating preparation, desorption time, stirring rate, desorption temperature, ionic strength, time and temperature of extraction. A Plackett-Burman design was performed for screening in order to determine the significant variables affecting the extraction efficiency. Then, the significant factors were optimized by a Box-Behnken design (BBD) and the response surface equations were derived. The detection limit and relative standard deviation (RSD) (n=5, c=50 μgL(-1)) for DMSe were 16 ngL(-1) and 4.3%, respectively. They were also obtained for DMDSe as 11ngL(-1) and 4.6%, respectively. The developed technique was found to be applicable to spiked environmental and biological samples.