NiFe-LDH/nylon 6 composite electrospun on polypropylene membrane: A new extractive device development for porous membrane protected micro-solid-phase extraction of organophosphate pesticides from fresh fruit juice samples coupled with liquid chromatography tandem mass analysis.

A unique strategy for developing porous membrane protected micro-solid phase extraction has been provided. An electrospun composite was fabricated on the sheet of membrane. To this end, NiFe-layered double hydroxide/Nylon 6 composite nanofibers were coated on a polypropylene membrane sheet followed by folding into a pocket shape, which were then utilized as a novel extractive device to extract of organophosphorus pesticides from fresh fruit juice samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The fabricated hybrid composites were successfully characterized. The effective parameters on extraction performance were investigated. LODs were 0.020-0.065 ng mL-1. Excellent linearity (R2≥0.996) was observed between 0.05 and 100.0 ng mL-1. RSDs% were in the range of 3.1-5.8% (intra-day, n = 3) and 2.6-5.5% (inter-day, n = 3×3). Satisfactory related recovery values within the acceptable range of 90.7-111.2% with RSDs% below 6.7% were achieved for the analysis of real samples.

Synthesis of imidazolium ionic liquid immobilized on magnetic mesoporous silica: A sorbent material in a green micro-solid phase extraction of multiclass pesticides in water.

In this study, we synthesized an imidazolium ionic liquid immobilized on magnetic mesoporous silica (IL-MMS) and evaluated its performance as a sorbent material for a green micro-solid phase extraction (µ-SPE) of multiclass pesticides in water. The synthesized IL-MMS was characterized by various analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analyses (N2 adsorption/desorption), Vibrating Sample Magnetometer (VSM), energy-dispersive spectroscopy (EDS) and Field emission scanning electron microscopy (FESEM). Our synthesized IL-MMS demonstrated excellent magnetic properties (31.5 emu/g), high surface area (1177.4 m2/g), proper pore size (⁓4.2 nm) and volume (1.80 cm3/g). Under optimized extraction conditions, the IL-MMS exhibited a high adsorption capacity for a variety of pesticides, including organophosphates, carbamates, and pyrethroids. The proposed µ-SPE method using IL-MMS showed good linearity (R2 > 0.99), low limits of detection (LODs) ranging from 0.04 to 1.63 ng/L, and suitable recovery rate was between 82.4% and 109.8% for different pesticides. In addition, the method also exhibited excellent reproducibility, with relative standard deviations (RSDs) of less than 8% for both intra and inter-day precision. In overall, the synthesized IL-MMS has proven to be a highly promising material for sorbent-based micro-solid phase extraction (µ-SPE) of multiclass pesticides in water. With its simple, efficient, and eco-friendly approach to pesticide analysis, this method shows great potential for future pesticide detection and monitoring efforts due to its sensitivity, accuracy, and adaptability to various environmental conditions.

ZIF67-derived porous carbon-reinforced electrospun nanofiber as an extractive phase for on-chip micro-solid-phase extraction of antifungals from biological fluids prior to liquid chromatography tandem mass spectrometry.

With a view to improving applicability as a sorbent while overcoming the challenges associated with its powdery nature, cobalt-doped zeolitic imidazolate framework (ZIF 67)-derived nanoporous carbon (Co-NPC) was employed as an additive in nanofiber through the process of electrospinning. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis were used to characterize the resulting nanocomposite. A microfluidic chip device with four layers, including two layers entailing spiral channels, was designed and employed to assess the analytical performance of the fabricated Co-NPC-reinforced electrospun composite. To do so, a folded piece of electrospun composite was sandwiched between two layers with spiral channels. Therefore, both sides of the folded composite acted as a sorptive phase to extract antifungal drugs as target analytes. The significant factors affecting the efficiency of the extraction process were investigated and optimized. Subsequently, the technique was verified through the utilization of liquid chromatography-tandem mass spectrometry (LC-MS/MS) by employing optimal parameters. The optimal conditions were applied to evaluate the figures of merit. A linear range was obtained for antifungal drugs within the range 0.25-200.0 ng ml-1 with an R2 value of ≥ 0.9914. The method demonstrated detection limits ranging between 0.08 and 0.40 ng ml-1. The intra-day and inter-day precisions were less than 6.9%. Relative recoveries exhibited variations between 91.4-106.8%, 95.9-103.6%, and 96.4-109.3% for ketoconazole, clotrimazole, and miconazole, respectively. The proposed approach yielded satisfactory results, demonstrating its efficiency.

Two fluorimetric determinations of acid α-glucosidase activity in dried blood spot: Pompe disease in Iranian population.

INTRODUCTION: Pompe disease is a lysosomal storage disorder. This study aimed to validate and compare 2 fluorimetric methods for measuring α-glucosidase acid activity in dried blood spot sample (DBS), with potential applications in neonatal screening, and disease follow-up of Pompe patients among the Iranian population for the first time. MATERIALS AND METHODS: The evaluation involved 3 enzyme levels and 7 parameters. The analysis included 141 Healthy individuals, 8 Pompe patients, and 10 obligate heterozygotes using reference and modified methods. RESULTS: Both methods exhibited highly linear calibration curves. The limit of detection (LOD) and limit of quantification (LOQ) were obtained in the micromolar concentration range in 2 methods. Inter-day and intra-day precision, expressed as relative standard deviations (RSD%) were calculated. The normal ranges were determined in healthy individuals. Receiver operating characteristic (ROC) curves were analyzed, and 2 parameters, total neutral α-glucosidase (NAG)/acid α-glucosidase (GAA) and pH ratio, were identified as cut-off values with excellent accuracy, sensitivity, and specificity for evaluating Pompe disease in both methods. CONCLUSIONS: Establishing and implementing these 2 methods for the Iranian population effectively differentiated between healthy and patient individuals. Method II, with its shorter incubation time, demonstrated practicality in the clinical setting.

Gold nanoparticles coated with PVP as a novel colorimetric sensor for sensitive and selective determination of Atenolol.

In this work, gold nanoparticles coated with polyvinylpyrrolidone (PVP-AuNPs) were used as a colorimetric probe for the sensitive, selective, simple, and rapid determination of atenolol (ATN). Indeed, atenolol triggered the aggregation of PVP-AuNPs via hydrogen bonding, electrostatic interactions, and dipole-dipole forces with PVP on the surface of AuNPs, causing the colloidal solution's color to shift from red to blue. SEM, TEM, FT-IR, UV-Vis, zeta potential, and other methods were used to characterise the PVP-AuNPs that were created as well as their aggregates. An excellent linear relationship between the absorption ratio (A690/A521) and the concentration of ATN in the range of 0.07-3.0 µM with a detection limit of 0.023 µM was discovered by optimising the experimental settings. The influence of potential interfering species on the measurement of ATN was investigated, and it was discovered that the developed colorimetric sensor had satisfactory selectivity. Finally, the presented method was used to measure ATN in tablet and blood plasma samples, and the obtained recovery values showed great promise for the use of the proposed sensor in clinical applications.

Correction: Fabrication of a reusable magnetic multi-walled carbon nanotube-TiO2 nanocomposite by electrostatic adsorption: enhanced photodegradation of malachite green.

[This corrects the article DOI: 10.1039/C4RA15593A.].

Poly (deep eutectic solvents) as a new class of sustainable sorbents for solid phase extraction: application for preconcentration of Pb (II) from food and water samples.

A new class of polymeric sorbents based on deep eutectic solvents (DESs) is introduced. These materials are obtained from simple and inexpensive precursors via an energy-efficient process. The primary benefit of these sorbents is that they possess the unique characteristics of DESs and porous materials simultaneously. Moreover, the possibility of tailoring deep eutectic solvents allows designing a specific polymer for a desired analyte, based on its physical and chemical properties. In this work, the deep eutectic solvent of tetrabutylammonium bromide and acrylic acid (1:2 molar ratio) was prepared and then polymerized under solventless condition. The synthesized polymer was characterized by FT-IR spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), and Brunauer, Emmett and Teller analysis (BET) to evaluate the properties of the sorbent. The poly (TBAB-2AA DES) was applied as a selective sorbent for preconcentration of lead from food and water samples prior to its quantification by flame atomic absorption spectroscopy (FAAS). Variable factors affecting the extraction were optimized, and under the optimum conditions, the calibration plot was linear in the range 5.0-250.0 µg L-1. The relative standard deviation was (for n = 5) (RSD) < 3%. The limit of detection (LOD) and the enhancement factor were found to be 2.0 µg L-1 and 50, respectively. Finally, the accuracy of the method was assessed by comparison of the results with those obtained by direct determination of lead using inductively coupled plasma mass spectrometry (ICP-MS) and spiked real samples. The obtained recoveries were between 92 and 106%. Graphical abstract.

Arginine-derived carbon nanoparticles for determination of Cr(VI) in water samples.

Hexavalent chromium, Cr(VI), is a toxic and carcinogenic ion that poses significant risks toward human health and the environment. Due to its extensive industrial use and high water solubility, Cr(VI) can easily contaminate drinking water sources. Therefore, it is essential to develop methods to detect Cr(VI) in water samples. Recently, carbon quantum dots - being biocompatible, easy to synthesize, and cost-effective fluorophores - have been successfully applied for the determination of different heavy metal ions. In this study, arginine-derived carbon nanoparticles were synthesized using a solvent-free one-pot thermal method. These carbon nanoparticles were characterized using transmission electron microscopy, dynamic light scattering analysis, infrared spectroscopy, ultraviolet-visible (UV-vis) light spectroscopy, fluorescence spectroscopy, and CHNO elemental analysis before being used to design a sensor for Cr(VI). The sensor's signal was optimized and the arginine-derived carbon nanoparticle-based Cr(VI) determination method was shown to have a limit of detection of 18 nM, a limit of quantification of 60 nM, and a linear response range of 0.06-100 µM. The sensor's selectivity toward Cr(VI) was studied and a potential interfering ion was identified and dealt with. Finally, the sensor was successfully applied for the determination of Cr(VI) in tap water and mineral water samples.

Developing a highly selective method for preconcentration and determination of cobalt in water and nut samples using 1-(2-pyridylazo)-2-naphthol and UV-visible spectroscopy.

BACKGROUND: Heavy metal contamination in water and agricultural products is a major concern that causes risks for human health. This article describes a highly selective approach to preconcentrate cobalt(II) (Co(II)) ions based on the standard UV-visible measurement of Co(II)-1-(2-pyridylazo)-2-naphthol complex at λ = 628 nm in water and nut samples. In this method, magnetic silica (mSiO2 ) was utilized as a practical sorbent and 1-(2-pyridylazo)-2-naphthol was employed as a complexing agent in the elution step. The adsorbent was characterized via X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy. The effects of the main variables (pH, adsorption time, sorbent amount, pH of eluent, ligand volume, and desorption time) were investigated and established. RESULTS: The maximum recovery was achieved at pH 7 ± 0.3, adsorption time of 60 min, sorbent amount of 40 mg, eluent pH 8 ± 0.2, ligand volume of 2 mL (16.95 × 10-4 mol L-1 ) and desorption time of 30 min. The linearity of dynamic range (10-500 µg L-1 ), limit of detection (0.32 µg L-1 ), relative standard deviation (3.04%), and preconcentration factor (25) show the reliability of the method. The sorbent was reusable 12 times. Selectivity and the effect of interference ions were successfully examined. The adsorption process of Co(II) ions on mSiO2 was investigated based on Langmuir and Freundlich isotherms. The Freundlich model was fitted with the system and the maximum capacity adsorption of mSiO2 for Co(II) adsorption is 2.35 mg g-1 . Then, the kinetics study revealed that the adsorption process of Co(II) ions on the mSiO2 follows the pseudo-first-order model. The thermodynamics parameters ΔG, ΔS, and ΔH were calculated. CONCLUSION: The method was fruitfully applied to preconcentrate Co(II) ions in water and nut samples. This method offers high selectivity and precision for determining Co(II) ions. © 2020 Society of Chemical Industry.

Determination of iron(II) and iron(III) via static quenching of the fluorescence of tryptophan-protected copper nanoclusters.

"Tryptophan-coated blue fluorescent copper nanocluster (CuNC@Trp) was prepared by a strategy where Trp acts as both the reducing and capping agent. The fluorescence of the CuNC, with excitation/emission peaks at 340/405 nm, is selectively quenched by iron(II) and iron(III) ions. Studying the mechanism of this interaction revealed that Fe2+ and Fe3+ ions can make a ground state complex with the protecting ligand which can result in quenching of the cluster emission. Structural and optical properties of the modified CuNC were investigated by ESI-MS, DLS, TEM, UV-vis and photoluminescence. The effects of pH value and temperature, time of interaction, and cluster volume were optimized. Under optimized conditions, the probe response is linear in concentration range of 10-1000 µM for Fe(II) and Fe(III) with the relative standard deviations of 0.13 and 0.14% (n = 5) respectively. The respective limits of detection are 3.0 and 2.2 µM. The method was successfully used for determination of trace amount of both ions in spiked water, blood and iron supplement tablets. The results were in good agreement with those obtained by the ICP-AES method." Graphical abstractThe scheme represents the synthesis of CuNC@Trp at basic conditions and at elevated temperature. The emission of the cluster decreases due to static quenching of fluorescence by iron ions.

Cuminum cyminum fruits as source of luteolin- 7-O-glucoside, potent cytotoxic flavonoid against breast cancer cell lines.

Cuminum cyminum is famous for its spicy fruits used for culinary and therapeutic properties worldwide. Brine shrimp test was performed for detecting cytotoxic fractions and subfractions. Ethyl acetate (EA) and hexane (HE) fractions demonstrated LC50 of 52.40 and 60.77 µg/ml against Artemia salina while other fractions showed no toxicity (LC50> 500 µg/ml). Bioguided elucidation of EA and HE fractions were carried out and cytotoxicity of pure compounds were investigated against breast cancer cell lines (MCF-7 and MDA-MB-231) and normal cell line (NIH/3T3) by MTT assay. Four flavone structures as luteolin, apigenin, luteolin-7-O-glucoside and apigenin-7-O-glucoside from EA and cuminoid A from HE were purified and identified. Luteolin-7-O-glucoside demonstrated potent anticancer activities against MCF-7 cell line (IC50 of 3.98 µg/ml) with selectivity index of 8.0. In conclusion, flavonoids especially luteolin-7-O-glucoside play a significant role in cytotoxic effect of C. cyminum fruits and can be introduced as candidate for chemopreventive and chemotherapeutic drugs.

Porous ionic liquid polymer: A reusable adsorbent with broad operating pH range for speciation of nitrate and nitrite.

Ionic liquids (ILs) are a class of fluids with unique physicochemical properties employing polymeric substances emerging new materials. Solidification of ILs into porous materials generates porous ionic liquid polymers that combine the unique characteristics of ILs with common porous materials and polymers. In this study, it's the first time the porous ionic liquid polymer was chosen as a sorbent for extraction and speciation of nitrite and nitrate. Porous IL was prepared through polymerization of 1-allyl-3-methylimidazolium bromide monomers in the presence of azobisisobutyronitrile (AIBN) and crosslinking of ethylene glycol dimethyl acrylate (EGDMA). Parameters affecting the adsorbent performance were optimized. Under the optimal conditions, correlation coefficient (R2) was 0.9996 and LOD was 0.1 µg L-1. This method presented the linearity in the concentration range between 0.1-100 µg L-1 and the relative standard deviation was 3.2%. Finally, the adsorption behavior of the obtained sorbent for nitrate and nitrite determination in various real samples was evaluated. The result indicates that the porous ionic liquid polymer showed high adsorption capacity (233 mg g-1). The convenient preparation of the porous ionic liquid material, as well as high adsorption capacity for anionic pollutants predicted its broad application potential in anion removal materials.

Magnetic Mn2O3 nanocomposite covered with N,N'-bis(salicylidene)ethylenediamine for selective preconcentration of cadmium(II) prior to its quantification by FAAS.

This article describes a method for highly selective preconcentration of Cd(II) via magnetic Mn2O3 coated by N,N'-bis(salicylidene)ethylenediamine (BSED). The metal oxide components were prepared via combining sol-gel and precipitation methods. Then, BSED was added as the third component of the composite. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, alternating gradient force magnetometry, and Fourier transform infrared spectroscopy were applied to characterize the materials. BSED selectively forms a complex with Cd(II), and the sorbent can then be magnetically separated. The preconcentration conditions were optimized as pH value (4.0 ± 0.5), sorbent amount (30 mg), adsorption time (20 min), eluent 2 M HNO3), eluent volume (1.5 mL) and desorption time (4 min). The quantification of Cd(II) was done by flame atomic absorption spectroscopy. The method has the following figures of merit: (a) a detection limit of 320 µg L-1, (b) a relative standard deviation of 1.1%, (c) an enhancement factor of 36, (d) a preconcentration factor of 33, and (e) a linear dynamic range that extends from 10 to 120 µg L-1. Other features include the use of safe reagents, fast and simple preparation, high selectivity and reliable analytical performance. The effects of potentially interfering ions were examined. The Dubinin-Radushkevich model and the pseudo second-order model are found to fit the adsorption behavior. The absorption is spontaneous and exothermic. The method was successfully applied to the determination of Cd(II) in (spiked) fruit samples. Graphical abstract Schematic presentation of a nanocomposite (Fe3O4 - Mn2O3 - Schiff base) that was prepared from MnCl2, H2O2, FeCl2, FeCl3, NH3, salicylaldehyde, ethylenediamine and tetraethylammonium hydroxide for the magnetic solid phase extraction of cadmium at trace levels.

Easily synthesized carbon dots for determination of mercury(II) in water samples.

In this work, a simple thermal method was used to synthesize carbon dots from citric acid and glycine precursors. It was found that Hg(II) ions can selectively quench the fluorescence emission of these carbon dots. Subsequently, a sensor was designed and optimized for the determination of Hg(II) ions. The limit of detection and quantification of the sensor were found to be 38 and 112 ppb, respectively. The sensor showed good selectivity toward Hg(II) ions and was successfully used for the determination of Hg(II) ions in mineral water samples.

Electrostatically in situ binding of zwitterionic glycine on the surface of MGO for determination of nitrite in various real samples.

Zwitterionic dispersive magnetic solid phase extraction (ZI-DMSPE) was developed through in situ binding of glycine on the magnetic graphene oxide, electrostatically. This highly selective sorbent was applied for the determination and preconcentration of trace levels of nitrite in soil, sausage, water samples (tap, mineral, and rain), and vegetables (potato, onion, spinach, radish, and lettuce) prior to its determination by UV-Vis spectrophotometry. The major advantage of the method is the analyte adsorption in both acidic and basic media. The sorbent was characterized by SEM, XRD, EDS, and FT-IR. Several parameters affecting ZI-DMSPE were optimized. Under the optimal conditions, LOD and RSD were obtained 17 ng L-1 and 1.3% respectively. Preconcentration factor and sorption capacity of the proposed method were 666 and 238 mg g-1 respectively. Accuracy was assessed by comparing results with those obtained by direct determination using ion chromatography and spiked real samples.

Poly(Acrolein-co-ß-Cyclodextrin) Functionalized Magnetic Nanoparticles for Selective CD45-Positive Cells Capturing.

In this work, a new magnetic nanocomposite was prepared for the specific isolation of CD45 positive cells. Acrolein (AC) and acrylated ß-cyclodextrin (ACD) were used as monomers in order to polymerize on the surface of Fe3O4 magnetic nanoparticles (MNPs) via surface initiated radical polymerization. Polyacrolein-ß-CD (PACD) functionalized Fe3O4 MNPs (Fe3O4@PACD) was achieved and subsequently, fluorescein conjugated IgG anti-human CD45 was immobilized onto Fe3O4@PACD. Antibody conjugation onto the latter nanocomposite was accomplished according to IgG encapsulation in cyclodextrin cavity and Schiff base formation between aldehyde groups of MNPs and primary amines of antibody. The characterization analysis of the bare Fe3O4, Fe3O4@PACD nanocomposite, and Fe3O4@PACD-Ab were investigated using XRD, VSM, FT-IR, H-NMR, TGA, SEM, TEM, and flow cytometry techniques. The results showed that the antibody has been successfully immobilized onto Fe3O4@PACD. Moreover, the fabricated nanocomposite was used for selective capturing of CD45+ cells among other peripheral blood mononuclear cells (PBMCs). The results of TEM and fluorescence microscopy confirmed the ability of the conjugated system for efficient cell capturing.

Modification of a steel fiber with a graphene based bucky gel for headspace solid-phase microextraction of volatile aromatic hydrocarbons prior to their quantification by GC.

A graphene based bucky gel-coated stainless steel fiber was prepared and applied to headspace solid phase microextraction of volatile organic compounds. Graphene was mixed with an ionic liquid to produce a bucky gel that displays the attractive features of both compounds. It can be directly deposited on an etched stainless steel wire to give the fiber for use in extraction of benzene, toluene, ethylbenzene and xylene (BTEX) isomers. The presence of graphene favors the π-interaction between the sorbent and aromatic analytes. The sorbent is thermally stable up to 300 °C and can be used more than 50 times. It was characterized by field emission scanning electron microscopy, FT-IR spectroscopy and thermogravimetric analysis. Under optimized conditions, linear responses were found in the range of 0.11-5000 µg L-1 for toluene, 0.15-5000 for benzene and o-xylene, 0.17-5000 for m- and p-xylene and 0.20-5000 for ethylbenzene. Limits of detection are between 0.03 and 0.06 µg L-1 (at an S/N ratio of 3). The run-to-run RSDs are <5.8% (for n = 6), and fiber-to-fiber RSDs are 4.1-9.2% (n = 4). The method was successfully applied to the extraction of BTEX isomers in spiked urine samples and gave recoveries between 88 and 105%. Graphical abstract Graphene based bucky gel (G-BG) was prepared by mixing an ionic liquid with graphene. It was physically deposited on stainless steel wire. The fiber was applied to the headspace solid phase microextraction (HS-SPME) of benzene, toluene, ethylbenzene and xylenes.

Synthesis of a magnetic WO3 nanocomposite for use in highly selective preconcentration of Pb(II) prior to its quantification by FAAS.

A novel sorbent consisting of WO3 and Fe3O4 is described for preconcentration of Pb(II). It was prepared without consumption of organic solvents. The nano composite was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, alternating gradient force magnetometer and Brunauer-Emmett-Teller. Having high surface area and being formed oxygen sheets propose the nanocomposite as a sorbent. Adsorption and desorption conditions were optimized and Pb(II) is quantified by flame atomic absorption spectroscopy. The sorbent can highly selectively preconcentrate Pb(II) at pH values between 3 and 7. The preconcentration time is short and sorbent is re-usable. Under the optimized conditions, the method has the following figures of merit: (a) limit of detection of 0.60 ng mL-1, (b) relative standard deviation (n = 5) of 0.87%, (c) preconcentration factor of 33.33 and (d) linearity of dynamic range (10-200 ng.mL-1). Isotherm adsorption, kinetic adsorption and thermodynamic adsorption were stablished. The material was applied to the preconcentration of Pb(II) from herbal medicines. Graphical abstract Schematic presentation of a nanocomposite (Fe3O4 - WO3) that was prepared from sodium tungstate (Na2WO4), oxalic acid, HCl and magnetic Fe3O4 nanoparticles for the magnetic solid phase extraction of lead at trace levels.

Enhanced headspace single drop microextraction method using deep eutectic solvent based magnetic bucky gels: Application to the determination of volatile aromatic hydrocarbons in water and urine samples.

A facile headspace single drop microextraction method was developed using deep eutectic solvent-based magnetic bucky gel as the extraction solvent for the first time. The hydrophobic magnetic bucky gel was formed by combining choline chloride/chlorophenol deep eutectic solvent and magnetic multiwalled carbon nanotube nanocomposite. Magnetic susceptibility, high viscosity, high sorbing ability, and tunable extractability of organic analytes are the desirable advantages of the prepared gel. Using a rod magnet as a suspensor in combination with the magnetic susceptibility of the prepared gel resulted in a highly stable droplet. This stable droplet eliminated the possibility of drop dislodgement. The prepared droplet made it possible to complete the extraction process in high temperatures and elevated agitation rates. Furthermore, using larger micro-droplet volumes without any operational problems became possible. These facts resulted in shorter sample preparation time, higher sensitivity of the method, and lower detection limits. Under the optimized conditions, an enrichment factor of 520-587, limit of detection of 0.05-0.90 ng/mL, and linearity range of 0.2-2000 ng/mL (coefficient of determination = 0.9982-0.9995) were obtained. Relative standard deviations were < 10%. This method was successfully coupled with gas chromatography and used for the determination of benzene, toluene, ethylbenzene, and xylene isomers as harmful volatile organic compounds in water and urine samples.