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1. The effect of Foeniculi aetheroleum essential oil (EO) on growth performance, nutrient utilisation, serum biochemistry, immune response, ileum morphology, microbial population and meat quality of broiler chickens fed a corn- or wheat-based diet were determined.2. A total of 360 broiler chickens were arranged in a 2 × 2 factorial assay in a completely randomised design with six replicates and 15 birds per experimental unit. Birds were fed corn- or wheat-based diets supplemented with (200 mg/kg) or without fennel EO.3. Birds fed wheat-based diets had lower BWG and FCR during grower period and lower FI during finisher period as compared to those fed corn-based diet (P < 0.05) whereas addition of fennel EO decreased chickens BWG during finisher period and EPEF, both in wheat or in corn-based diets. Dietary treatments had no effect on serum glucose, triglyceride, cholesterol, LDL-cholesterol, AST, ALT, ALP, and MDA concentrations (P < 0.05).4. Antibody titres against avian influenza and sheep red blood cell antibody titres, crude protein and crude fat utilisation, villus height, crypt depth and epithelium thickness were not influenced by dietary treatments (P > 0.05). Inclusion of Fennel EO to the corn-based diet resulted in greater villus width and villus surface area while it reduced lamina propria thickness (P < 0.05). Fennel EO reduced ileal E. coli and Lactobacillus spp. populations (P < 0.05). Dietary treatments had no significant effect on meat pH, cooking loss, drip loss, crude protein, crude fat content and cholesterol concentration of breast and thigh meat, total phenolic and MDA concentrations, and breast meat sensory parameters (P > 0.05).5. These results showed that addition of fennel EO to wheat-based diets had a negative effect on chicken growth performance variables and decreased gut E. coli populations. However, immunity, meat quality and nutrient utilisation were not affected by dietary treatments.

A headspace microextraction by packed sorbent technique (HS-MEPS) was developed that is assisted by cooling the extraction phase and, in the same time, heating the sample matrix. The innovated cooling assisted HS-MEPS system was optimized for the extraction and HPLC determination of volatile polycyclic aromatic hydrocarbons (PAHs) in solid samples. Amino ethyl-functionalized SBA-15 was used as a nanoporous sorbent for packing the conical hub of the MEPS syringe. For efficient extraction of PAHs, several parameters such as the nature and mass of sorbent, eluent type, elution volume, extraction temperature and number of draw-eject cycles of the syringe were studied and optimized. Under the optimal experimental conditions, only 2 mg of the sorbent was sufficient by applying a temperature of 0 °C to the sorbent while the sample was heated up to 150 °C. Linear calibration curves (R 2  > 0.95) were obtained for all the studied PAHs and their quantitation limits were in the range of 0.042-0.25 ng g -1 . The method was successfully applied to the extraction and HPLC analysis of PAHs in some polluted soil samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

A metal-organic framework/polyaniline composite was synthesized and doped with silica nanoparticles. The structure and morphology of the composite were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. It was packed inside a cartridge and evaluated for the solid-phase extraction of thymol and carvacrol, followed by gas chromatography with flame ionization detection measurement. The influence of the important experimental variables on the efficiency of the proposed method, including pH, ionic strength, volume of sample solution and type, and volume of eluent were studied and optimized. Under the optimal conditions, the relative standard deviations were found to be 3.8 and 9.8% for thymol and carvacrol, respectively, and the corresponding limits of detection were 0.1 and 1.0 ng/mL. The linear dynamic ranges for the calibration curves of the analytes were 10-10000 ng/mL, with determination coefficients (R 2 ) > 0.993. The limits of quantifications were found to be 0.01 and 0.5 μg/mL, for thymol and carvacrol, respectively. The prepared nanocomposite sorbent was applied successfully to the extraction and determination of thymol and carvacrol in Lamiaceae plant extracts and a honey sample, with relative recoveries in the range of 90.28-122.0%., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

SBA-15 and MCM-41 nanoporous silica sorbents were synthesized and functionalized by amine groups and used, for the first time, for packing a needle trap device (NTD). The characteristics of the synthesized SBA-15 and MCM-41 sorbents were investigated by X-ray diffraction, scanning electron microscopy and Fourier transfer infrared spectroscopy. The NTD coupling to gas chromatography with a flame ionization detector (GC-FID) was carried out to extract and determine polycyclic aromatic hydrocarbons (PAHs) in contaminated soil samples. The performances of the sorbents for the extraction of PAHs were compared under identical conditions and the NH2-SBA-15 sorbent showed superior results. Extraction temperature, extraction time, recycling gas flow rate, sample moisture, desorption time and desorption temperature were evaluated and optimized for the system. Under the optimum conditions, detection limits of 0.0004-0.0035 μg g-1, quantitation limits of 0.001-0.01 μg g-1 and relative standard deviations of 7.4-14.9% were obtained for the PAHs. The results showed the more effectiveness of this sorbent for the extraction of the PAHs compared to that of a commercial sorbent. The method was successfully applied for the extraction and determination of PAHs in polluted soil samples collected from gas stations, with recoveries ranging from 64 to 112%.

In this work, voltammetric data recorded by a glassy carbon electrode (GCE) was used to investigate the interactions of tolcapone (Tasmar, TAS) with human serum albumin (HSA) at the electrode surface. The recorded voltammetric data was also combined with spectroscopic data to construct an augmented data matrix which was analysed by multivariate curve resolution-alternating least squares (MCR-ALS) as an efficient chemometric tool to obtain more information about TAS-HSA interactions. The results of MCR-ALS confirmed formation of one complex species (HSA-TAS 2 ) and application of MCR-BANDS to the results of MCR-ALS confirmed the absence of rotational ambiguities and existing unambiguous and reliable results. Binding of TAS to HSA was also modeled by molecular docking and the results showed that the TAS was bound to sub-domain IIA of HSA which were compatible with the ones obtained by recording experimental data. Hard-modeling of combined voltammetric and spectroscopic data by EQUISPEC helped us to compute binding constant of HSA-TAS 2 complex species which was compatible with the binding constant value obtained by direct analysis of experimental data. Finally, a new electroanalytical method was developed based on TAS-HSA interactions for determination of HSA in two ranges of 0-541 nM and 541-1200 nM with a limit of detection of 0.04 nM and a sensitivity of 0.02 μA nM -1 ., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A low-cost and reliable cooling/heating-assisted microextraction (CHaME) instrument was designed and fabricated for use in different modes of microextraction methods. The CHaME setup is able to cool down the sorbent and simultaneously heat the sample in a wide temperature range. Consequently, it can create a large thermal gap between the sorbent and the sample matrix, to promote the release of analytes from the sample tissue and enhance their effective trapping on the microextraction phase. The primary versions of the instrument have previously been evaluated, coupled with different modes of solid- and liquid-phase microextraction strategies. Compared with conventional microextraction systems, it is able to extract volatile organic compounds from complicated solid matrices more effectively, rapidly and without any need for a sample preparation step. In this research, the final and compact version of the CHaME instrument was fabricated and employed in a cooling/heating-assisted needle trap device (CHaME-NTD) for microextraction of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil samples, prior to GC-FID determination. An aminosilica/graphene oxide nanocomposite was synthesized, covalently attached to cotton (Am-Si/GO/Cot), packed inside a needle, and applied as an effective sorbent for trapping of the analytes. The influence of experimental parameters on the extraction efficiency of the TC-NTD-GC-FID strategy was evaluated and optimized. Under the optimal conditions, linear dynamic ranges (LDRs), limits of detection (LODs), and relative standard deviations (RSDs) for the PAHs were 0.001-2.0 μg g-1, 5-38 pg g-1, and 6.2-9.8% (n = 6), respectively. The CHaME-NTD-GC-FID procedure was compared with the traditional NTD-GC-FID method. Additionally, the Am-Si/GO/Cot nanocomposite sorbent was compared with the most frequently used commercial sorbents. The results demonstrated the remarkable performance of the CHaME-NTD procedure and the Am-Si/GO/Cot composite sorbent. The developed setup was also used for the extraction and determination of PAHs in contaminated soil samples, through the CHaME-NTD-GC-FID procedure.

A stainless steel fiber was made porous and adhesive by platinization and then coated by nanostructured polypyrrole (PPy), using an appropriate electrophoretic deposition (EPD) method. The morphological surface structure and functional groups of the PPy-coated fiber were studied using SEM (Scanning electron microscope) instrument. The prepared fiber was used for comparison of direct immersion (DI) and electroenhanced direct immersion solid-phase microextraction (EE-DI-SPME) of nicotine in human plasma and urine samples followed by gas chromatography flame ionization detector (GC-FID) determination. The effects of the influential experimental parameters on the efficiency of the DI-SPME and EE-DI-SPME methods, including the pH and ionic strength of the sample solution, applied Direct current (DC) voltage, extraction temperature and time and stirring rate, were optimized. Under the optimal conditions, the calibration curves for the DI-SPME-GC-FID and EE-DI-SPME-GC-FID methods were linear over the ranges of 0.1⁻10.0 μg mL -1 and 0.001⁻10.0 μg mL -1 , respectively. The relative standard deviations (RSDs, n = 6) were found to be 6.1% and 4.6% for the DI and EE strategies, respectively. The LODs (limit of detection) of the DI-SPME-GC-FID and EE-DI-SPME-GC-FID methods were found to be 10 and 0.3 ng mL -1 , respectively. The relative recovery values (for the analysis of 1 µg mL -1 nicotine) were found to be 91⁻110% for EE-DI-SPME and 75⁻105% for DI-SPME. The enrichment factors for DI-SPME and EE-DI-SPME sampling were obtained as 38,734 and 50,597, respectively. The results indicated that EE-SPME was more efficient for quantitation of nicotine in biological fluids. The developed procedure was successfully carried out for the extraction and measurement of nicotine in real plasma and urine samples., Competing Interests: The authors have no conflict of interest to declare.

A low-cost, sensitive and reliable reduced-pressure headspace solid-phase microextraction (HS-SPME) setup was developed and evaluated for direct extraction of residual solvents in commercial antibiotics, followed by determination by gas chromatography with flame ionization detection (GC-FID). A stainless steel narrow wire was made porous and adhesive by platinization by a modified electrophoretic deposition method and coated with a polyaniline/multiwalled carbon nanotube nanocomposite. All experimental variables affecting the extraction efficiency were investigated for both atmospheric-pressure and reduced-pressure conditions. Comparison of the optimal experimental conditions and the results demonstrated that the reduced-pressure strategy leads to a remarkable increase in the extraction efficiency and reduction of the extraction time and temperature (10 min, 25 °Ϲ vs 20 min, 40 °Ϲ). Additionally, the reduced-pressure strategy showed better analytical performances compared with those obtained by the conventional HS-SPME-GC-FID method. Limit of detections, linear dynamic ranges, and relative standard deviations of the reduced-pressure HS-SPME procedure for benzene, toluene, ethylbenzene, and xylene (BTEX) in injectable solid drugs were obtained over the ranges of 20-100 pg g -1 , 0.02-40 μg g -1 , and 2.8-10.2%, respectively. The procedure developed was successful for the analysis of BTEX in commercial containers of penicillin, ampicillin, ceftriaxone, and cefazolin. Graphical abstract Schematic representation of the developed RP-HS-SPME setup.

The surface of a stainless-steel wire was platinized using electrophoretic deposition method to create a high-surface-area with porous and cohesive substrate. The platinized fiber was coated by the polypyrrole/graphene oxide nanocomposite by electropolymerization and accommodated into a stainless-steel needle to fabricate an in-needle coated fiber. The developed setup was coupled to gas chromatography with flame ionization detection and applied to extract and determine polycyclic aromatic hydrocarbons (naphthalene, fluorene, phenanthrene, fluoranthene, and pyrene) in complicated solid matrices, along with reinforcement of the extraction by cooling the sorbent, using liquid carbon dioxide. To obtain the best extraction efficiency, the important experimental variables including extraction temperature and time, temperature of cooled sorbent, sampling flow rate, and desorption condition were studied. Under the optimal condition, limits of detection for five studied analytes were in the range of 0.2-0.8 pg/g. Linear dynamic ranges for the calibration curves were found to be in the range of 0.001-1000 ng/g. Relative standard deviations obtained for six replicated analyses of 1 ng/g of analytes were 4.9-13.5%. The reinforced in-needle coated fiber method was successfully applied for the analysis of polycyclic aromatic hydrocarbons in contaminated soil samples., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A polyaniline/multi-wall carbon nanotubes (PANI/MWCNT) composite was electrodeposited on the interior surface of a platinized stainless steel capillary needle and used to prepare an inside needle capillary adsorption trap (INCAT) device. The platinization expanded the interior adsorbing surface of the needle and made it more porous and cohesive for nanocomposite film. The nanocomposite was characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The fabricated INCAT was fixed into a cooling capsule to fabricate a cooling-assisted INCAT (CA-INCAT) system. The CA-INCAT device was used to extract polycyclic aromatic hydrocarbons (PAHs) from solid samples followed by gas chromatography-flame ionization detection (GC-FID) determination. To obtain the best extraction efficiency, the important experimental variables were studied and optimized. Under the optimal conditions, the limits of detection (LODs) for the studied PAHs were in the range of 0.002-0.02ngg -1 . Linear dynamic ranges (LDRs) for the calibration curves were found to be 0.1-30,000ngg -1 . Relative standard deviations (RSDs%) for six replicated analysis of 1ngg -1 PAHs were obtained 7.7-11%. The CA-INCAT-GC-FID method was successfully applied for the extraction and determination of PAHs in contaminated soil samples. The results were in agreement with those obtained by a validated ultrasound-assisted solvent extraction (UA-SE) method., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A low-cost and simple cooling-assisted headspace liquid-phase microextraction device for the extraction and determination of 2,6,6-trimethyl-1,3 cyclohexadiene-1-carboxaldehyde (safranal) in Saffron samples, using volatile organic solvents, was fabricated and evaluated. The main part of the cooling-assisted headspace liquid-phase microextraction system was a cooling capsule, with a Teflon microcup to hold the extracting organic solvent, which is able to directly cool down the extraction phase while the sample matrix is simultaneously heated. Different experimental factors such as type of organic extraction solvent, sample temperature, extraction solvent temperature, and extraction time were optimized. The optimal conditions were obtained as: extraction solvent, methanol (10 μL); extraction temperature, 60°C; extraction solvent temperature, 0°C; and extraction time, 20 min. Good linearity of the calibration curve (R(2) = 0.995) was obtained in the concentration range of 0.01-50.0 μg/mL. The limit of detection was 0.001 μg/mL. The relative standard deviation for 1.0 μg/mL of safranal was 10.7% (n = 6). The proposed cooling-assisted headspace liquid-phase microextraction device was coupled (off-line) to high-performance liquid chromatography and used for the determination of safranal in Saffron samples. Reasonable agreement was observed between the results of the cooling-assisted headspace liquid-phase microextraction high-performance liquid chromatography method and those obtained by a validated ultrasound-assisted solvent extraction procedure., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Acrylamide is a potentially toxic and carcinogenic substance present in many high-consumption foods. Recently, this matter has been placed in category of "reasonably anticipated to be a human carcinogen" by National Toxicology Program (NTP). Therefore, simple and cost-effective determination of acrylamide in food samples has attracted intense interest. The most reported techniques for this purpose are GC-MS and LC-MS, which are very expensive and available in few laboratories. In this research, for the first time, a rapid, easy and low-cost method is introduced for sensitive and precise determination of acrylamide in foodstuffs, using gas chromatography-flame ionization detection (GC-FID) system after its direct trapping in the upper atmosphere of samples by headspace solid-phase microextraction (HS-SPME). The effects of main experimental variables were studied and the optimized parameters were obtained as the type of fiber, carboxen/divinylbenzene/polydimethylsiloxane (CAR/DVB/PDMS); extraction time, 30 min; extraction temperature, 60°C; moisture content, 10 µL water per 1g of sample; desorption time, 2 min; and desorption temperature, 230°C. The linear calibration graph was obtained in the range of 0.77-50 µg g(-1), with regression coefficient of 0.998. The detection and quantification limits of the proposed method were 0.22 and 0.77 µg g(-1), respectively. The recoveries, for different food samples, were 79.6-95.7%. The repeatability of measurements, expressed as relative standard deviation (RSD), were found to be 4.1-8.0% (n=9). The proposed HS-SPME-GC-FID method was successfully carried out for quantifying of trace levels of acrylamide in some processed food products (chips and French fries), sold in open local markets., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In this study, the application of a novel nanomaterial composite was investigated in two microextraction techniques of solid-phase microextraction and a needle trap device in a variety of sampling conditions. The optimum sampling temperature and relative humidity were 10°C and 20%, respectively, for both techniques with two sorbents of graphene/silica composite and polydimethyl siloxane. The two microextraction techniques with the proposed sorbent showed recoveries of 95.2 and 94.6% after 7 days. For the needle trap device the optimums desorption time and temperature were 3 min at 290°C and for SPME these measures were 1 and 1.5 min at 240-250°C for the graphene/silica composite and polydimethyl siloxane, respectively. The relative standard division obtained in inter- and intra-day comparative studies were 3.3-14.3 and 5.1-25.4, respectively. For four sample the limit of detection was 0.021-0.25 ng/mL, and the limit of quantitation was 0.08-0.75 ng/mL. The results show that the graphene/silica composite is an appropriate extraction media for both techniques. Combining an appropriate sorbent with microextraction techniques, and using these in conjunction with a sensitive analytical instrument can introduce a strong method for sampling and analysis of occupational and environmental pollutants in air., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A simple, low-cost, and effective cooling/heating-assisted headspace solid-phase microextraction (CHA-HS-SPME) device, capable of direct cooling the fiber to low temperatures and simultaneous heating the sample matrix to high temperatures, was fabricated and evaluated. It was able to cool down the commercial and handmade fibers for the effective tapping of volatile and semi-volatile species in the headspace of complex solid matrices, with minimal manipulation compared with conventional SPME. The CHA-HS-SPME system can create large temperature gaps (up to 200 °C) between the fiber and the sample matrix, because the cooling process is directly applied onto the fiber. Different effective experimental parameters for the fabrication of the CHA-HS-SPME device as well as for the extraction and determination of polycyclic aromatic hydrocarbons (PAHs) from solid samples were evaluated and optimized. The proposed device coupled to GC-FID was successfully applied for the extraction and determination of PAHs in contaminated soils without any sample pretreatment step. Good agreement was observed between the results obtained by the proposed CHA-HS-SPME-GC-FID method and those achieved by validated method., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In this paper we describe the application of a needle trap microextraction device packed with graphene nanoplatelets for the sampling and analysis of perchloroethylene in dry cleaning. The study was carried out in two phases. First the parameters for the sampling and analysis of perchloroethylene by NTD were evaluated and optimized in the laboratory. Then the sampler was used to determine the levels of perchloroethylene in a dry-cleaning shop. In the laboratory phase of the study the performance of the NTD packed with the proposed sorbent was examined in a variety of sampling conditions to evaluate the technique. The technique was also compared with NTDs packed with PDMS as well as SPME with Carboxen/PDMS-coated fibers. Both the NTDs and SPME performed better at lower sampling temperatures and relative humidity levels. The post-sampling storage times for a 95% recovery of the analyte were 5, 5 and 3 days for NTD-graphene, NTD-PDMS and SPME-CAR/PDMS respectively. The optimum desorption time was 3 min for NTDs packed with either graphene or PDMS and 1 min for SPME-CAR/PDMS. The limits of detection for the GC/MS detection system were 0.023 and 0.25 ng mL(-1) for NTDs packed with graphene and PDMS and 0.014 ng mL(-1) for SPME coated with CAR/PDMS. In the second stage of the study the evaluated technique was applied to the sampling and analysis of perchloroethylene in dry cleaning. In this environment the performance of the NTD-graphene as a field sampler for PCE was similar to that of the SPME-CA/PDMS, and better than the NIOSH 1003 method which had greater measurement variations. The results show that a NTD packed with carbonic graphene nanoplatelets and used as an active exhaustive sampling technique is effective for determination of VOC and HVOC occupational/environmental pollutants in air., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A needle trap device (NTD) packed with silica composite of multi-walled carbon nanotubes (MWCNTs) prepared based on sol-gel technique was utilized for sampling and analysis of volatile organohalogen compounds (HVOCs) in air. The performance of the NTD packed with MWCNTs/silica composite as sorbent was examined in a variety of sampling conditions and was compared with NTDs packed with PDMS as well as SPME with Carboxen/PDMS-coated fibers. The limit of detection of NTDs for the GC/MS detection system was 0.01-0.05 ng mL(-1) and the limit of quantitation was 0.04-0.18 ng mL(-1). The RSD were 1.1-7.8% for intra-NTD comparison intended for repeatability of technique. The NTD-MWCNTs/silica composite showed better analytical performances compared to the NTD-PDMS composite and had the same analytical performances when compared to the SPME-Carboxen/PDMS fibers. The results show that NTD-MWCNTs-GC/MS is a powerful technique for active sampling of occupational/environmental pollutants in air., (Copyright © 2013 Elsevier B.V. All rights reserved.)

This paper describes a new approach that combines needle trap devices (NTDs) with a newly synthesized silanated nano material as sorbent for sampling and analysis of HVOCs in air. The sol-gel technique was used for preparation of the single wall carbon nanotube (SWCNT)/silica composite as sorbent, packed inside a 21-gauge NTD. Application of this method as an exhaustive sampler device was investigated under different laboratory conditions in this study. Predetermined concentrations of each analyte were prepared in a home-made standard chamber, and the effects of experimental parameters, such as temperature, humidity, sampling air flow rate, breakthrough volume and storage time on NTD, and the sorbent performance were investigated. The proposed NTD was used in two different modes and two different injection methods, and an NTD with a side hole, a narrow neck glass liner and syringe pump assisted injection of carrier gas were applied. The NTD packed with SWCNTs/silica composite was compared to the NTD packed with PDMS and also SPME with CAR/PDMS. For four compounds, LOD was 0.001-0.01 ng mL(-1), LOQ was 0.007-0.03 ng mL(-1), and the relative standard division for repeatability of method was 2.5-6.7%. The results show that the incorporation of NTD and SWCNTs/silica composite is a reliable and effective approach for the sampling and analysis of HVOCs in air. Coupling this system to GC-MS make it more sensitive and powerful technique., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Introduction: Headspace solid-phase microextraction (HS-SPME) and headspace single-drop microextraction (HS-SDME) methods have never been used for the extraction and analysis of the volatile compounds of Myrtus communis. For that reason, in this work, these two techniques were compared with the traditional hydrodistillation (HD) extraction technique., Objective: To compare SPME and SDME with HD for the extraction and analysis of Myrtus communis volatiles., Methodology: Three extraction methods, i.e. SPME, SDME and HD, coupled to gas chromatography-mass spectrometry were used and optimised for the analysis of Myrtus communis volatiles. The SPME extraction was performed on a 100 µm PDMS fibre and for SDME a drop of n-octadecane containing 0.7% of menthol as internal standard was used as extracting solvent. The results were compared from different viewpoints including efficiency of extraction, different kinds of species extracted and quantity of extracted compounds with HD., Results: The main analytes extracted by SPME were found to be α-pinene, limonene, 1,8-cineole, linalool, linalyl acetate, α-terpinyl acetate and geranyl acetate, whereas for SDME α-pinene, limonene, 1,8-cineole, linalool, linalyl acetate and β-myrcene were extracted as major components. Hydrodistillation could extract α-pinene, limonene, 1,8-cineole, linalool, α-terpineol, linalyl acetate, α-terpinyl acetate, geranyl acetate and cis-isoeugenol better than other volatiles from Myrtus communis., Conclusion: The results demonstrated that HS-SPME and HS-SDME can be applied successfully for the extraction and separation of volatiles in aromatic plants, and these techniques are easier to perform, and more effective than HD for collection of more volatile compounds., (Copyright © 2011 John Wiley & Sons, Ltd.)

CMK-3 nanoporous carbon was prepared and characterized as a highly porous fiber coating, with a highly ordered carbon framework, for solid-phase microextraction (SPME). The nanomaterial was immobilized onto platinum, stainless steel and copper metal wires for preparation of new SPME fibers. The copper-CMK-3 fiber showed superior properties and therefore was applied for extraction of some phenolic compounds in combination with GC-MS. For optimization of the extraction conditions, a simplex optimization method was used. The selected conditions were: sample volume 13 ml, extraction temperature 56°C, extraction time 7 min, ultrasonic time 5.5 min, pH 5 and salt concentration 8.9%. The selected fiber showed some selectivity towards the polar phenolic compounds and its extraction efficiency was better than a commercial PDMS fiber. Linear calibration curves with correlation coefficients better than 0.99 and detection limits in the range from 0.002 to 0.068 μg mL(-1) were obtained for the fiber. No significant change was observed in the extraction efficiency of the new SPME fiber over at least 40 extractions. The fiber was successfully used for the determination of phenolic compounds in natural water samples., (Copyright © 2011 Elsevier B.V. All rights reserved.)

A reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) method coupled to HPLC was developed for the extraction of hydroxytyrosol (HTy) and tyrosol (Ty) from virgin olive oil. In this first application of the RP-DLLME method to non-polar samples, the phenolic compounds were directly extracted into an aqueous micro-drop, which could be injected into a chromatography column without any further pretreatment. A glass test tube with lengthened conical bottom was fitted inside a centrifuge tube in this work for more efficient withdrawal of the sedimented phase with a microsyringe. The volumes of water and ethyl acetate, the pH of water and the centrifuge time as four effective parameters on the extraction were optimized by a central composite design (response surface) method. Five replicated analyses under the optimized conditions (i.e., 0.2 mL ethyl acetate as disperser and 100 µL water at pH 11 as the extraction solvent) resulted in recoveries of 104.3 and 97.6%, and relative standard deviations of 5.75 and 4.57 for HTy and Ty, respectively. The detection limit of the method (3σ) was 0.043 mg L(-1) for HTy and 0.032 mg L(-1) for Ty. The method was successfully applied to the determination of HTy and Ty in five olive oil samples., (2011 © The Japan Society for Analytical Chemistry)

A reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) method was developed for the preconcentration and direct HPLC determination of oleuropein in olive's processing wastewater (OPW) and olive leaves extracts. In conventional DLLME, the sedimented phase is a micro-drop of a chlorinated organic solvent that is not compatible with RP-HPLC. Therefore, solvent evaporation and reconstitution with an appropriate solvent is often required. In RP-DLLME, this problem was overcome by overturning the solvent polarity in the ordinary DLLME and replacing the organic solvent with water. A central composite chemometrics design was used for multivariate optimization of the effects of five different parameters influencing the extraction efficiency of the method. In the optimized conditions, a mixture of 1.4 mL of an ethyl acetate extract of sample and 40 microL water (pH 5.0) was rapidly injected into 5.3 mL of cyclohexane. After centrifugation of the formed cloudy mixture, a micro-drop of the aqueous phase was sedimented at the conical bottom of the centrifuge tube. This phase, that contained the preconcentrated and partially purified analyte, was directly injected into an RP-HPLC column for analysis. A mean extraction recovery of 102.5 (+/-4.5) % with enrichment factors exceeding 38, was obtained for five replicated analysis. The detection limit of the method (3 sigma) for OE was 0.02 microg L(-1) for OPW and 2 x 10(-3) mg kg(-1) for olive leaves samples. The results showed that, RP-DLLME is a promising technique which is quick, easily operated and can be directly coupled to HPLC., (Copyright (c) 2009 Elsevier B.V. All rights reserved.)

In the present study ninety nine polished white rice samples were collected in three areas, all over Lorestan Province located in the west of Iran, and analysed for six elements by Flame Atomic Absorption Spectrometry (FAAS). For individual elements, Zinc (Zn) showed the highest concentration among the analysed essential elements with a mean of 28.6 mg kg(-1) and next to copper (Cu) of 22.8 mg kg(-1). Analysis of the essential and toxic elements for possible inter-area variation by ANOVA showed that there are significant differences between the areas. There was no significant difference between areas for Zn concentrations. Most of the samples nearly contained world wide average concentration of iron (Fe) and Zn in rice grains that were reported by various researches. But, the content of calcium (Ca) in the rice samples produced in Lorestan Province were much lower than other countries, meanwhile Cu concentrations were much higher than other studies. Cadmium (Cd) and Lead (Pb) concentrations in the sampled rice were lower in comparison with their upper limits (0.1 and 0.2 mg kg(-1) for Cd and Pb, respectively) approved by Iranian Ministry of Health. Therefore, it can be concluded that there is no health problems result from Lorestan rice consumption, for these two elements.

A simple device was developed that makes the use of lighter than water organic solvents feasible in dispersive liquid-liquid microextraction (DLLME) method. In the ordinary DLLME, the fact that a heavier than water organic solvent must be used, to be sedimented at the conical bottom of a centrifuge tube, limits the applications of this method in some extent. In the developed method, a glass tube with a narrow neck is inserted inside the centrifuge tube. After phase separation, the organic solvent is accumulated in the narrow neck of the device and therefore, can be simply collected by a micro-syringe. The DLLME method with the proposed device was tested for the enrichment of glycyrrhizic acid from aqueous extracts of licorice before analysis by a HPLC method. n-Hexanol and acetone were used as the organic and disperser phases, respectively. Effects of pH, salt concentration and phase volumes on the extraction of the analyte were optimized using a central composite (response surface) design. Under the optimized conditions (i.e. pH 1.3, ionic strength 0.2 mol L(-1), n-hexanol 140 microL and acetone 0.8 mL) an extraction recovery of 104.1 (+/-5.1)% and an enrichment factor of 54 were obtained. The proposed method was successfully applied for the study of glycyrrhizic acid's level of licorice roots grown in three regions of Lorestan province, Iran, with different climate conditions.

Nanoporous silica (SBA-15) was prepared and functionalized with 3-[Bis(2-hydroxyethyl)amino] propyl-triethoxysilane (HPTES) to be used as a highly porous fiber coating material for solid-phase microextraction (SPME). The prepared HPTES-SBA-15 particles had a lengthy morphology and a specific surface area of 790 m(2) g(-1). They were characterized by N(2) sorption analyses, scanning electron microscopy and thermogravimetric analysis. The prepared nanomaterial was immobilized onto a copper wire for fabrication of the SPME fiber. The fiber was evaluated for the extraction of BTEX and some phenolic compounds in combination with GC-MS. For optimization of factors affecting the extraction efficiency of the phenolic compounds, a simplex optimization method was used. The proposed fiber showed some selectivity towards the polar phenolic compounds with extraction efficiencies better than a PDMS commercial fiber. The repeatability for one fiber (n=5), expressed as relative standard deviation (RSD), was between 6.5% and 9.8% and the reproducibility for five prepared fibers was between 8.2% and 11.3% for the test compounds. No significant change was observed in the extraction efficiency of the new SPME fiber over 50 extractions. The fiber was successfully applied to the determination of phenolic compounds in spiked river water and sewage samples. Thus, HPTES-SBA-15 fiber is a promising alternative to the commercial fibers as it is robust, selective, highly porous and easily and inexpensively prepared.

A new automated headspace solid-phase microextraction (HS-SPME) sampling device was developed, with the capability of heating the sample matrix and simultaneously cooling the fiber coating. The device was evaluated for the quantitative extraction of polycyclic aromatic hydrocarbons (PAHs) from solid matrices. The proposed device improves the efficiency of the release of analytes from the matrix, facilitates the mass transfer into the headspace and significantly increases the partition coefficients of the analytes, by creating a temperature gap between the cold-fiber (CF) coating and the hot headspace. The reliability and applicability of previously reported cold-fiber devices are significantly enhanced by this improvement. In addition, it can be easily adopted for full automation of extraction, enrichment and introduction of different samples using commercially available autosampling devices. Sand samples spiked with PAHs were used as solid matrices and the effect of different experimental parameters were studied, including the extraction temperature, extraction time, moisture content, and the effect of sonication and modifier under optimal experimental conditions, linear calibration curves were obtained in the range of 0.0009-1000 ng/g, with regression coefficients higher than 0.99 and detection limits that ranged from 0.3 to 3 pg/g. Reproducible, precise and high throughput extraction, monitoring and quantification of PAHs were achieved with the automated cold-fiber headspace solid-phase microextraction (CF-HS-SPME) device coupled to GC-flame ionization detection. Determination of PAHs in certified reference sediments using the proposed approach exhibited acceptable agreement with the standard values.

A new simple and efficient homogeneous liquid-liquid extraction method for the selective separation and preconcentration of molybdenyl ions was developed. alpha-Benzoin oxime (ABO) was investigated as a complexing ligand, and perfluorooctanoate ion (PFOA(-)) was applied as a phase-separator agent under strongly acidic conditions. Under the optimal conditions ([ABO]=2.1x10(-3)M, [PFOA(-)]=1.8x10(-2)M, [HNO(3)]=1.7M, [acetone]=11.8% (v/v)), 10mug of molybdenum in 5ml aqueous phase could be extracted quantitatively into 40mul of the sedimented phase. The maximum concentration factor was 125-fold. Thiocyanate was applied as a chromogenic reagent for the direct spectrophotometric determination of molybdenum in the sedimented phase. The reproducibility of the proposed method is at the most 2.4%. The influence of the type and concentration of acid solution, the concentration of ABO, the type and volume of the water-miscible organic solvent, the concentration of PFOA(-), and the effect of different diverse ions on the extraction and determination of molybdenum(VI) were investigated. The proposed method was applied to the extraction and determination of molybdenum(VI) in natural water, Spinach, and Lucerne samples. A satisfactory agreement exists between the results obtained by the proposed method and those reported by GF-AAS.

A simple and efficient method for the selective separation and preconcentration of Ag+ using homogeneous liquid-liquid extraction was developed. Tetraspirocyclohexylcalix[4]pyrrole (TSCC4P) was synthesized and investigated as a suitable selective complexing ligand for Ag+. Zonyl FSA (FSA) was applied as a phase-separator agent under mild pH conditions. Under the optimal conditions ([TSCC4P] = 3.4 x 10(-4) M, [THF] = 25.0% v/v, [FSA] = 1.25% w/v, and pH = 4.5), 5 microg of Ag+ in 6.0 ml aqueous phase could be extracted quantitatively into 20 microl of the sedimented phase. The maximum concentration factor was 300-fold. The limit of detection of the proposed method was 0.005 ng/ml. The reproducibility of the proposed method was at most 3.5%. The influence of the pH, type and volume of the water-miscible organic solvent, concentration of FSA, concentration of the complexing ligand and the effect of different diverse ions on the extraction and determination of Ag+ were investigated. The proposed method was applied to the extraction and determination of Ag+ in different water samples.

A simple and efficient method for the selective separation and preconcentration of uranium(VI) using homogeneous liquid-liquid extraction was developed. Tri-n-octylphosphine oxide (TOPO) and tri-n-butylphosphate (TBP) were investigated as complexing ligands, and perfluorooctanoate ion (PFOA-) was applied as a phase separator agent under strongly acidic conditions. Under the optimal conditions ([PFOA-] = 1.7 x 10(-3) M, [TOPO] = 5.4 x 10(-4) M, [HNO3] = 0.3 M, [acetone] = 3.2% v/v) 10 microg of uranium in 40 ml aqueous phase could be extracted quantitatively into 8 microl of the sedimented phase. The maximum concentration factor was 5000-fold. However, an effort for the quantitative extraction using TBP was inefficient and the percent recovery was at most 56.7. The influence of the type and concentration of acid solution, optimum amount of the ligand, type and volume of the organic solvent, concentration of PFOA, volume of the aqueous sample and effect of different diverse ions on the extraction and determination of uranium(VI) were investigated. The proposed method was applied to the extraction and determination of uranium(VI) in natural water samples.

A new simple and reliable method has been developed to selectively separate and concentrate ultra trace amounts of copper ion in aqueous samples for subsequent measurement by atomic absorption spectrometry (AAS). The Cu(2+) ions are adsorbed selectively and quantitatively during passage of aqueous solutions through octadecyl silica membrane disks modified with bis(2-hydroxyphenylamino) glyoxime. The retained copper ions then stripped from the disk with a minimal amount of 0.2M nitric acid solution as eluent, and determined by AAS. The proposed method permitted large enrichment factors of about 100 or higher. The limit of detection of the proposed method is 0.004ngml(-1). The maximum capacity of the membrane disks modified with 25mg of ligand was found to be 280+/-32mug of copper(II). The effects of various cationic interferences on the percent recovery of copper in binary mixtures were studied. The method was successfully applied to the recovery and determination of copper in several water samples.

A simple and reliable method for rapid extraction and determination of uranium in natural waters using octadecyl-bonded silica membrane disks modified with tri-n-octylphosphine oxide (TOPO) and spectrophotometry with dibenzoylmethane is presented. Extraction efficiency and the influence of sample matrix, type, and optimum amount of extractant, flow rates, and type and minimum amount of organic eluent were evaluated. The maximal capacity of the membrane disks modified by 50 mg of TOPO was found to be 4033 micrograms of uranium. The limit of detection of the proposed method is 100 ng/1000 mL. The method was applied to the extraction and determination of uranium in natural waters.

A simple, rapid and sensitive flow injection spectrophotometric method for determination of selenium (0.005-1.5 mug ml(-1)) is described. The method is based on the catalytic effect of Se(IV) on the reduction reaction of thionine (TN) with sulphide ion, monitored spectrophotometrically at 598 nm. The detection limit is 5 ng ml(-1) the relative standard deviation for eight replicate measurements is 1.1% for 1 mug ml(-1) of selenium. The sampling rate is 25-30 samples h(-1). The procedure was applied successfully to the determination of selenium in real samples.