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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 ionpairing 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Herein, an efficient graphene oxide/FeO@polythionine (GO/FeO/PTh) nanocomposite sorbent was introduced for magnetic solid-phase extraction combined with high-performance liquid chromatography-ultraviolet detection of duloxetine (DLX) in human plasma. To prepare the sorbent, an oxidative polymerization of thionine on the surface of magnetic GO was utilized while PTh was simply used as a surface modifier to improve extraction efficiency. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis, vibrating sample magnetometry, Fourier transform-infrared spectroscopy and Brunauer-Emmett-Teller technique were applied to characterize the prepared nanoparticles. Firstly, effective parameters controlling the performance of the extraction process were evaluated in detail and optimized. Under the optimized conditions, calibration curve showed linearity in the range of 2-2500 ng mL with regression coefficient corresponding to 0.998. Limits of detection (LOD, S/N = 3) and quantification (LOQ, S/N = 10) were 0.5 and 2 ng mL, respectively. Reasonable intra-assay (3.5-4.5%, n = 6) and inter-assay (3.8-6.7%, n = 9) precision represented acceptable performance of the procedure. The applicability of the method was successfully extended to the determination of DLX in human plasma after oral administration of 60 mg single dose of the drug and finally some pharmacokinetic data was achieved. [ABSTRACT FROM AUTHOR]

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−1were obtained for formic acid and acetic acid, respectively. A reasonable repeatability (5.8% ≤ RSD ≤ 8.8%,n= 6) and satisfactory linearity (r2≥ 0.997) illustrated the performance of the method. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study was designed to examine the chemical composition of essential oil andin vitroantioxidant and antimicrobial activity of the essential oil and methanol extracts ofEucalyptus largiflorensF. Muell. The chemical composition of the hydrodistilled essential oil of the leaves ofE. largiflorenswas 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 forP. 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 extract (15.1 ± 0.7 μg/ml) showed the highest radical-scavenging activity. In the second case, the inhibition capacity (%) of the nonpolar subfraction (92.7% ± 2.5) was found to be the stronger one. Finally, the total amounts of phenol constituents in the polar subfraction (142.6 ± 0.9 μg/mg), nonpolar subfraction (68.6 ± 0.4 μg/mg), and the oil (36.0 ± 0.6 μg/mg) were determined. [ABSTRACT FROM PUBLISHER]

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 [C6MIM][PF6] (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 ( r2≥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. [ABSTRACT FROM AUTHOR]

Abstract: A simple and efficient liquid-phase microextraction (LPME) technique was developed using directly suspended organic microdrop coupled with gas chromatography–mass spectrometry (GC–MS), for the extraction and the determination of phthalate esters (dimethyl phthalate, diethyl phthalate, diallyl phthalate, di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBP), dicyclohexyl phthalate and di-2-ethylhexyl phthalate (DEHP)) in water samples. Microextraction efficiency factors, such as nature and volume of the organic solvent, temperature, salt effect, stirring rate and the extraction time were investigated and optimized. Under the optimized extraction conditions (extraction solvent: 1-dodecanol; extraction temperature: 60°C; microdrop volume: 7μL; stirring rate: 750rpm, without salt addition and extraction time: 25min), figures of merit of the proposed method were evaluated. The values of the detection limit were in the range of 0.02–0.05μgL−1, while the R.S.D.% value for the analysis of 5.0μgL−1 of the analytes was below 7.7% (n =4). A good linearity (r 2 ≥0.9940) and a broad linear range (0.05–100μgL−1) were obtained. The method exhibited enrichment factor values ranging from 307 to 412. Finally, the designed method was successfully applied for the preconcentration and determination of the studied phthalate esters in different real water samples and satisfactory results were attained. [Copyright &y& Elsevier]

Methicillin-Resistant Staphylococcus aureus (MSRA) has become a frequent cause of serious infections. Extended hospitalization and antibiotic therapy have been identified as additional risk factors for MRSA carrier and infection. The aim of this study was to determine the incidence of MRSA infections in the hospitals affiliated to Hamedan University of Medical Sciences. Seventy S. aureus clinical strains were isolated from patients from June 2005 to June 2006 and examined by PCR and conventional microbiological tests. Then, the antibiotic susceptibility to methicillin/oxacillin and other antibiotics were performed by Disc Diffusion Agar (DDA). The results of this study showed that methicillin resistance gene was detected in 35 (50%) and 22 (31.4%) cases by PCR and DDA, respectively. The results of antibiotic susceptibility assays also showed there were high resistance MRSA strains to penicilin (100%), cloxacillin (91.4%), tetracycline (74.2%), cotrimoxazole (68.5%), erythromycin (68.5%) and less resistance to rifampin (11.4). Two MRSA also had decreased susceptibility to vancomycin. But the strains of Methicillin-Sensitive S. aureus (MSSA) showed high sensitivity to all antibiotics profiles except to penicillin (complete resistance). As a conclusion, the resistance to methicillin/oxacillin of S. aureus in Hamedan hospitals has reached to 50% and they show multidrug resistance. [ABSTRACT FROM AUTHOR]

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 (RSD<10.3%, 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.

Objective: To identify Pseudomonas aeruginosa (P. aeruginosa) from the skin biopsy specimens in burn wound infections by multiplex polymerase chain reaction (M-PCR) and detection of antimicrobial susceptibility of isolates from culture., Methods: We conducted this cross-sectional study in 140 patients with wound infections who admitted to the referral burn center of Motahari, Tehran, Iran, during a 12-month period from 2005-2006. Skin biopsy specimens were aseptically taken from each patient, one for PCR and one for bacterial culture. A M-PCR test based on the simultaneous amplification of 2 lipoprotein genes: oprI and oprL, was used to directly detect fluorescent pseudomonades and P. aeruginosa in skin biopsy specimens. The susceptibility of P. aeruginosa isolates to 16 antibiotics was determined using the disc diffusion method., Results: Out of 140 biopsy specimens, M-PCR detected 66 (47.2%) isolates, while culture detected 57 (40.7%) isolates as P. aeruginosa. Positive results for both genes which observed only for P. aeruginosa, while only one gene, oprI, was amplified from other fluorescent pseudomonades n=12 and all other bacterial tested n=62 were negative by the amplification test. The most effective antibiotics against isolate of P. aeruginosa were cefepime (79%), azetreonam (76%), ticarcillin-clavulanic acid (68%), tobramycin (62%), and amikacin (61%)., Conclusion: Multiplex PCR assay appears promising for the rapid and sensitive detection of P. aeruginosa from the burned skin biopsy specimens. Simultaneous amplification of 2 lipoprotein genes: oprI and oprL, could detect P. aeruginosa, and oprI gene only for other fluorescent pseudomonades.