In this study, new and efficient method, magnetic solid phase extraction coupled with dispersive liquid-liquid microextracton (MSPE-DLLME) combined with gas chromatography-flame ionization detector (GC-FID) was developed for the preconcentration and determination of permethrin and deltamethrin in water samples. Several factors influencing the extraction efficiency including amount of sorbent, sorption time, type of extraction solvent and its volume, type of disperser solvent and its volume and elution time were investigated and optimized. Using optimum extraction conditions, dynamic linear range of 0.5-100 L-1 for both, limits of quantification (LOQs) of 0.6 L-1 for both and limits of detection (LODs) of 0.01 L-1 for both were obtained. Finally, the method was successfully applied for the extraction and determination of permethrin and deltamethrin in water samples in the range of micrograms per litre with RSDs < 4 %.

Abstract The aim of this study was to examine mutations in the quinolone-resistance-determining region (QRDR) of gyrA and parC genes in Pseudomonas aeruginosa isolates. A total of 100 clinical P. aeruginosa isolates were collected from different university-affiliated hospitals in Tabriz, Iran. Minimum inhibitory concentrations (MICs) of ciprofloxacin and levofloxacin were evaluated by agar dilution assay. DNA sequences of the QRDR of gyrA and parC were determined by the dideoxy chain termination method. Of the total 100 isolates, 64 were resistant to ciprofloxacin. No amino acid alterations were detected in gyrA or parC genes of the ciprofloxacin susceptible or ciprofloxacin intermediate isolates. Thr-83 → Ile substitution in gyrA was found in all 64 ciprofloxacin resistant isolates. Forty-four (68.75%) of them had additional substitution in parC. A correlation was found between the number of the amino acid alterations in the QRDR of gyrA and parC and the level of ciprofloxacin and levofloxacin resistance of the P. aeruginosa isolates. Ala-88 → Pro alteration in parC was generally found in high level ciprofloxacin resistant isolates, which were suggested to be responsible for fluoroquinolone resistance. These findings showed that in P. aeruginosa, gyrA was the primary target for fluoroquinolone and additional mutation in parC led to highly resistant isolates.

In this work, the synthesized Fe3O4 nanoparticles was coated by sodium dodecyl sulfate and then it was used as a sorbent in mixed-hemimicelle solid phase extraction of some amphetamines, as psychoactive drugs, from biological samples. This extraction method was combined with dispersive liquid-liquid microextraction to enhance enrichment factors of targeted analytes. Effect of different parameters influencing the hybrid extraction performance, such as sodium dodecyl sulfate amount and sample pH, were investigated. The method showed linearity in the range of 1.0-250 and 2.0-250 µg L-1 for the most of analytes in urine and plasma samples, respectively. The limits of detection, based on signal to noise of 3, were found 0.1-0.2 and 0.3-0.5 µg L-1 in urine and plasma samples, respectively. The results of the intra-day and inter-day precision were less than 13.5% for all amphetamines. The amounts of relative recoveries in spiked urine and plasma samples were found in the range of 90-96 and 87-93%, respectively.

Chamomile, Matricaria recutita L. from family of Asteracae, is a well-known medicinal plant in folk medicine cultivated all over the world. Chamomile essential oil is widely used in pharmaceutical, cosmetic, and food industries. This paper focuses on isolation methods and chemical constituents of essential oils from Matricaria recutita L. in Iran as to optimize these methods and achieving the proper economic procedures. The volatile constituents of Matricaria recutita L. cultivated in Iran were extracted by different methods of extraction by microwave usage, pilot plants and laboratory scale. The oil yields obtained from microwave was 0.08%, laboratory scale 0.06%, pilot 0.06% and pilot with heating element 0.07% . Essential oils were identified by GC and GC/MS. A total of 34 components were identified and significant qualitative and quantitative differences were observed amongst the studied. The main constituents of the essential oils of the studied three different methods were as follows: Microwave were α-bisabolol oxide A (42.3%), chamazulene (15.1%), α-bisabolol oxide B (9.6%), (Z,Z)-farnesol (8.1%) and in laboratory scale were cis-pinocamphone (73.5%), α-bisabolol oxide A (7.9%), in pilot were α-bisabolol oxide A (62.1%), chamazulene (10.2%), (Z,Z)-farnesol (8.3%) and in pilot with heating element were α-bisabolol oxide A (50.5%), E- β - farnesene (12.8%), chamazulene (12.3%) . The best method of extraction was pilot method ,because α-bisabolol oxide A (62.1%), chamazulene (10.2%), were major components, which are showing different pharmacological activities like anti-inflammatory, anti-cancer, anti-allergic, a treatment for stress and depression.

The purpose of this study is to prepare a new ion imprinted polymer for MoVI with high selectivity. Ion-imprinted polymer (IIP) particles were synthesized by thermally copolymerization. For the synthesis of the ion imprinted polymer, the ion pair of (MoVI-thiocyanate) and NR4+ was used. The ion pair was precipitated in an aqueous phase and then dissolved in acetonitrile as a porogen. The imprinted ion was removed using 10% (v/v) methanol in HCl (0.5 mol L-1). The unleached and leached IIP particles were characterized by infrared spectroscopy, thermogravimetric analysis, surface area analysis, scanning electron microscopy and energy dispersive X-ray analysis. The use of the new MoVI-IIP in solid phase extraction revealed a maximum adsorption capacity of 3.77 mg MoVIper gram of MoVI-IIP in optimum conditions of extraction. The selectivity coefficients of the IIP for Mo in comparison with other metal ions were also evaluated. The proposed Mo-IIP was successfully applied for MoVI determination in different types of water samples.

In this study, dispersive liquid-liquid microextraction based on the solidification of floating organic droplets was used for the preconcentration and determination of thorium in the water samples. In this method, acetone and 1-undecanol were used as disperser and extraction solvents, respectively, and the ligand 1-(2-thenoyl)-3,3,3-trifluoracetone reagent (TTA) and Aliquat 336 was used as a chelating agent and an ion-paring reagent, for the extraction of thorium, respectively. Inductively coupled plasma-optical emission spectrometry was applied for the quantitation of the analyte after preconcentration. The effect of various factors, such as the extraction and disperser solvent, sample pH, concentration of TTA and concentration of aliquat336 were investigated. Under the optimum conditions, the calibration graph was linear within the thorium content range of 1.0-250 µg L-1 with a detection limit of 0.2 µg L-1. The method was also successfully applied for the determination of thorium in the different water samples.

A method for the determination of trace amounts of palladium was developed using homogeneous liquid-liquid microextraction via flotation assistance (HLLME-FA) followed by graphite furnace atomic absorption spectrometry (GFAAS). Ammonium pyrrolidine dithiocarbamate (APDC) was used as a complexing agent. This was applied to determine palladium in three types of water samples. In this study, a special extraction cell was designed to facilitate collection of the low-density solvent extraction. No centrifugation was required in this procedure. The water sample solution was added to the extraction cell which contained an appropriate mixture of extraction and homogeneous solvents. By using air flotation, the organic solvent was collected at the conical part of the designed cell. Parameters affecting extraction efficiency were investigated and optimized. Under the optimum conditions, the calibration graph was linear in the range of 1.0-200 µg L-1 with a limit of detection of 0.3 µg L-1. The performance of the method was evaluated for the extraction and determination of palladium in water samples and satisfactory results were obtained. In order to verify the accuracy of the approach, the standard addition method was applied for the determination of palladium in spiked synthetic samples and satisfactory results were obtained.

Homogeneous liquid-liquid microextraction via flotation assistance (HLLME-FA) was investigated for the extraction of molybdenum from the water samples. Alizarin Red S and cetyl trimethylammonium bromide (CTAB) were used as a complexing ligand and ion-pairing reagent, respectively. The enriched analyte in the floated organic phase was determined by electrothermal atomic absorption spectrometry (ETAAS). In this work, low density organic solvent was used and no centrifugation was required in this procedure. A special extraction cell was designed to facilitate the collection of the low-density extraction solvent. By using air flotation, the organic solvent was collected at the conical part of the designed cell. Under the optimum conditions, the method performance was studied in terms of linear dynamic range (0.5-200 µg L-1), linearity (r2 > 0.991), precision (repeatability < 10.0 %). Also, the limit of detection (LOD) of 0.1 µg L-1 was obtained for molybdenum. The proposed method has been successfully applied for the determination of the molybdenum in water samples.

In this study, a simple and efficient ultrasound-assisted emulsification microextraction (USAEME) method combined with gas chromatography (GC) was developed for the preconcentration and determination of oxadiazon in water and soil samples. In this method, fine droplets of toluene were formed and dispersed in the sample with the help of ultrasonic waves which accelerated the formation of a fine cloudy solution without using disperser solvents. Several factors influencing the extraction efficiency, such as the nature and volume of organic solvent, extraction temperature, ionic strength and centrifugation time, were investigated and optimized. Using optimum extraction conditions a detection limit of 0.1 μg L-1 and a good linearity in a calibration range of 0.25-250 μg L-1 were achieved for the analyte in a river water sample. This proposed method was successfully applied to the analysis of oxadiazon in water and soil samples.

A determinação de chumbo e cádmio por espectrometria de absorção atômica de chama após a extração de fase sólida do óxido de grafeno (GO) utilizando o 4-acetamidotiofenol (ATP) como reagente quelante foi descrita. PM6 semi-empírico e a teoria de densidade funcional PBE foram os métodos usados na investigação do mecanismo de adsorção dos complexos em folhas de GO. Os principais fatores que influenciam a pré-concentração e determinação de analitos (pH, quantidade de ATP, tipo e concentração de eluente, fluxo e volume de amostra) foram examinados em detalhe. O efeito de íons interferentes no fator separação-pré-concentração também foi investigado. Para soluções de Pb(II) e Cd(II) 1,0 µg L-1, o fator de pré-concentração chegou a 250 (em condições otimizadas). Os limites de detecção para Pb(II) e Cd(II) foram 170 e 80 ng L-1, respectivamente. A validade do método proposto foi checada com materiais de referência padrão e foi aplicado com sucesso na determinacao de traços de Pb(II) e Cd(II) em amostras de água, ervas e peixe com recuperação de 99,4-103,5%.

The determination of lead and cadmium by flame atomic absorption spectrometry after solid phase extraction on graphene oxide column with use of 4-acetamidothiophenol (ATP) as chelating reagent was described. PM6 semi-empirical and PBE density functional theory methods were used to investigation of adsorption mechanism of the complexes on GO sheet. The main factors influencing the preconcentration and determination of the analytes (pH, ATP amount, eluent type and concentration, flow rate and sample volume) were examined in detail. The effect of interfering ions on the separation-preconcentration of analytes was also investigated. For Pb(II) and Cd(II) solutions of 1.0 µg L-1, the preconcentration factor was as high as 250 (under the optimized conditions). The detection limits for Pb(II) and Cd(II) were 170 and 80 ng L-1, respectively. The validity of the proposed method was checked with standard reference materials and it has been successfully applied for the determination of trace Pb(II) and Cd(II) in water, herbal and fish samples with the recoveries of 99.4-103.5%.

Um método novo foi desenvolvido para pré-concentração e determinação de compostos de ecstasy, 3,4-metilenodioxiamfetamina (MDA), 3,4-metilenodioximetilamfetamina (MDMA), 3,4-metilenodioxietilamfetamina (MDEA) e 3,4-metilenodioxipropilamfetamina (MDPA), em amostras de urina utilizando microextração líquido-líquido dispersiva (DLLME) e cromatografia gasosa com detector por ionização em chama (GC-FID). O método foi baseado na formação de gotículas de um extratante orgânico em soluções preparadas utilizando água, solvente orgânico imiscível (CS2) dissolvido em solvente dispersor miscível em água (acetona). A fase orgânica, que extraiu MDA, MDEA, MDMA e MDPA da solução da amostra preparada, foi separada por centrifugação. Parâmetros que afetam a eficiência da extração foram investigados e otimizados. Sob condições ideais, as linearidades do método foram 1,0-500 µg L-1 para MDEA e MDPA e 2,5-500 µg L-1 para MDA e MDMA. Os limites de detecção (LOD, S/N = 3, razão sinal ruído) foram no intervo de 0,3 a 0,8 µg L-1. O método foi aplicado com sucesso na determinação de analitos em amostras de urina.

A new method was developed for preconcentration and determination of ecstasy compounds, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethylamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA) and 3,4-methylenedioxypropylamphetamine (MDPA), in urine samples using dispersive liquid-liquid microextraction (DLLME) and gas chromatography (GC) with flame ionization detection (GC-FID). The method was based on the formation of tiny droplets of an organic extractant in prepared sample solution using water, immiscible organic solvent (CS2) dissolved in water-miscible organic disperser solvent (acetone). The organic phase, which extracted MDA, MDEA, MDMA and MDPA from the prepared sample solution, was separated by centrifugation. Parameters affecting extraction efficiency were investigated and optimized. Under the optimum conditions, linearities of the method were 1.0-500 µg L-1 for MDEA and MDPA and 2.5-500 µg L-1 for MDA and MDMA. The limits of detection (LODs, S/N = 3, signal-to-noise ratio) were in the range from 0.3 to 0.8 µg L-1. The method was successfully applied to the determination of analytes in urine samples.

A furan-triazole derivative has been explored as an ionophore for preparation of a highly selective Pr(III) membrane sensor. The proposed sensor exhibits a Nernstian response for Pr(III) activity over a wide concentration range with a detection limit of 5.2×10-8 M. Its response is independent of pH of the solution in the range 3.0-8.8 and offers the advantages of fast response time. To investigate the analytical applicability of the sensor, it was applied successfully as an indicator electrode in potentiometric titration of Pr(III) solution and also in the direct and indirect determination of trace Pr(III) ions in some samples.

Transference of resistance determinants by integrons is one of the important factors that can contribute to the increase in multi-resistant bacteria. We determined the prevalence and class of integrons among multi-drug resistant (MDR) Escherichia coli strains isolated from clinical specimens in Tabriz teaching hospitals. Firstly, susceptibility of 140 isolates to 13 antibiotics was determined using the disc diffusion method. Then, prevalence and class of integrons was detected in MDR strains by PCR-RFLP. One hundred five (75%) of total 140 isolates were uropathogenic Escherichia coli (UPEC). Other pathotypes included were: diarrheagenic Escherichia coli (13; 9.3%), sepsis-associated E. coli (5; 3.6%) and newborn meningitis-associated E. coli (2; 1.4%). Antibiotic resistance patterns were as follows: amoxicillin 99.3%, gentamicin 33.6%, tetracycline 72.8%, ceftazidime 46.4%, co-trimoxazole 75%, imipenem 1.4%, ciprofloxacin 47.6%, norfloxacin 50.7%, cephalothin 77.8%, amikacin 12.1%, nitrofurantoin 12.9%, chloramphenicol 20.7% and nalidixic acid 60.7%. One hundred eighteen (84.2%) of tested isolates were multi-drug resistant. Prevalence of integrons was confirmed in 27.1% of MDR isolates. intI1 and intI2 were detected respectively in 22.05% and 5.08% of MDR strains. No intI3 was detected. Resistance to gentamicin, amikacin and chloramphenicol was significantly associated with the presence of integrons. These results showed high resistance of E. coli to routine antibiotics, however, in consideration of low prevalence of integrons among these strains, we can conclude that antibiotic resistance genes in these strains presumably carried on elements other than integrons.