Proposed Microextraction Method Research Articles

Modified Peanut Shell as an Eco-Friendly Biosorbent for Effective Extraction of Triazole Fungicide Residues in Surface Water and Honey Samples before Their Determination by High-Performance Liquid Chromatography.

An eco-friendly sample preparation method that is based on the use of a modified peanut shell as an efficient biosorbent for the extraction of triazole residues before their analysis by high-performance liquid chromatography was reported. The four triazole fungicides were separated on a Purospher STAR RP-18 endcapped (4.6 × 150 mm, 5 μm) column with a mobile phase of 50% (v/v) acetonitrile at a flow rate of 1.0 mL min–1 and detection wavelength set at 220 nm. Peanut shells modified by didodecyldimethylammonium bromide were selected as an effective biosorbent material in the microextraction method. Scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy were used to characterize the biosorbent. The effect of dominant parameters on the proposed microextraction method including the amount of sorbent, kind and concentration of surfactant, sodium hydroxide concentration, kind and amount of salt, sample volume, adsorption time, kind and volume desorption solvent, and desorption time was studied. Under the optimum condition, a good analytical performance for the proposed microextraction method was obtained with a wide linear range within the range of 9–1000 μg L–1, and low limits of detection (0.03 μg L–1 for all analytes) were obtained. Enrichment factors were achieved within the range of 30–51. The intra and interday precision values were evaluated in terms of percentage relative standard deviations (%RSD) and were less than 0.09 and 5.34% for the retention time and peak area, respectively. The proposed microextraction methods were used for extraction and analysis of triazole fungicides in water and honey samples. The recoveries in a satisfactory range of 70.0–118.8% were obtained.

An In Situ Formation of Ionic Liquid for Enrichment of Triazole Fungicides in Food Applications Followed by HPLC Determination.

An in situ formation of ionic liquid was used for preconcentration of four triazole fungicides in food samples. The microextraction method was used for the first time in the literature for preconcentration of triazole fungicides. In the developed method, tributylhexadecylphosphonium bromide ([P44412]Br) and potassium hexafluorophosphate (KPF6) were used for the formation of hydrophobic ionic liquid. After centrifugation, the fine microdroplets were produced in one step, providing the extraction step in a quick and environmentally friendly manner. The functional group of the hydrophobic ionic liquid was investigated using FT-IR. Various extraction parameters were studied and optimized. In the extraction method, 0.01 g of [P44412]Br and 0.01 g of KPF6, centrifugation at 4500 rpm for 10 min were used. The optimized technique provided a good linear range (90–1000 μg L−1) and high extraction recovery, with a low limit of detection (30–50 μg L−1). Methods for the proposed in situ formation of ionic liquid were successfully applied to honey, fruit juice, and egg matrices. The recoveries were obtained in a satisfactory range of 62–112%. The results confirmed the suitability of the proposed microextraction method for selective extraction and quantification of triazole fungicides.

Development of monolith/aminated carbon nanotubes composite-based solid-phase microextraction of phenoxycarboxylic acids herbicides in water and soil samples.

In this study, a new adsorbent based on monolith/aminated carbon nanotubes composite was facilely prepared and employed as the extraction phase of multiple monolithic fibers solid-phase microextraction for the capture of phenoxycarboxylic acids herbicides. The adsorbent was fabricated by mingling aminated carbon nanotubes in the poly (allylthiourea-co-ethylene glycol dimethacrylate) monolith. Various techniques were employed to characterize the morphology, structure, and pore size of the prepared adsorbent. The proposed microextraction method displayed satisfactory capture performance towards studied analytes through multi-interactions such as hydrogen-bonding, hydrophobic and π-π interactions. Under the optimized conditions, a sensitive and reliable method to quantify trace analytes in water and soil samples was developed. The limits of detection were in the ranges of 0.13-0.25 μg/L and 0.20-0.61 μg/kg for water and soil samples, respectively. The practicality of the introduced method was demonstrated by applying it to monitor the contents of studied analytes in environmental water and soil samples. Satisfactory fortified recoveries (76.4-119%) and reproducibility were obtained. The achieved results well demonstrated that the suggested microextraction technique can efficiently extract phenoxycarboxylic acids and the developed method exhibits a promising potential for reliable and sensitive quantification of trace analytes in complex samples.

Applications of porous frameworks in solid-phase microextraction.

Porous frameworks are a term of attracting solid materials assembled by interconnection of molecules and ions. These trendy materials due to high chemical and thermal stability, well-defined pore size and structure, and high effective surface area gained attention to employ as extraction phase in sample pretreatment methods before analytical analysis. Solid-phase microextraction is an important subclass of sample preparation technique that up to now different configurations of this method have been introduced to get adaptable with different environments and analytical instruments. In this review, theoretical aspect and different modes of solid-phase microextraction method are investigated. Different classes of porous frameworks and their applications as extraction phase in the proposed microextraction method are evaluated. Types and features of supporting substrates and coating procedures of porous frameworks on them are reviewed. At the end, the prospective and the challenges ahead in this field are discussed.

A green and simple liquid-phase microextraction based on deep eutectic solvent for the erythrosine prior to its UV–VIS spectrophotometric detection

A simple, sensitive, effective and rapid liquid-phase microextraction (LPME) method based on deep eutectic solvent (DES) was developed for the preconcentration and determination of erythrosine in the drug, water and powdered fruit juice samples prior to its UV–VIS spectrophotometric determination. In the DES-LPME study, the analytical parameters affected on extraction efficiency of the analyte were optimized. Under the optimum experimental conditions, the limits of detection and limit of quantification were obtained as 0.53 µg L−1 and 1.78 µg L−1, respectively. The preconcentration factor was calculated as 100. Accuracy of the proposed microextraction method has been checked by analyzing the addition–recovery studies to in real samples and satisfactory results were obtained.

Liquid Chromatographic Determination of Aromatic Amines in Water Samples after Gold Nanoparticles Coated Membrane Microextraction

A novel microextraction technique was developed for aromatic amines using gold nanoparticles coated membrane. The preparation of the extraction device involves with the synthesis of gold nanoparticles via the reduction of AuCl3 by hydroxyethyl cellulose followed by coating to the polyethersulfone membrane. The simple extraction procedures involved placing the extraction device in a stirred aqueous sample solution, followed by desorption in an organic solvent using ultrasonication. The extract was analyzed by high performance liquid chromatography. Optimal extraction conditions include 50 min extraction time, 20 min desorption time, 30 mL sample volume, sample pH 10, 5 % NaCl content and 17 mg sorbent mass coupled with 100 μL desorption solvent. The performance of the extraction device in the absence and presence of gold nanoparticles was investigated. Enrichment factors ranged from 148 (for 3-nitroaniline) to 200 (for 3,4- dichloroaniline). The calibration results exhibited good linearity (r2 = 0.9931-0.9988) within the range 0.5-20 μg/L. The limits of detection were 0.3-0.7 μg/L and RSDs (n = 6) 10-19%. Comparison was made with solid-phase extraction. The method was subsequently applied to municipal wastewater samples. The proposed microextraction method offers advantages such as easy operation, high recovery, faster extraction, minimal use of organic solvent and elimination of tedious solvent evaporation and reconstitution steps.

Extraction and determination of tricyclic antidepressants in real samples using air-dispersed liquid-liquid microextraction prior to gas chromatography and flame ionization detection.

In the present research, a novel microextraction method was used based on dispersive liquid-liquid microextraction using low-density solvent for the determination of trace amounts of amitriptyline and doxepin as model compounds in human plasma and spring water samples before gas chromatography and flame ionization detection. The parameters influencing the extraction efficiencies including type of the extracting solvent, volume of the aqueous sample solution (donor phase), volume of the extraction solvent (acceptor phase), the number of air-injection, and the effects of pH and ionic strength were optimized. Under the optimized conditions, the obtained enrichment factors were >80. By plotting peak areas of the sample solutions versus various concentrations of the analytes, calibration curves were obtained which show the linear ranges of 10-3000ng/mL with correlation coefficients of >0.996. The precision of the method was calculated <4.2 and the limit of detection was 1ng/mL for two analytes. The proposed microextraction method was used for the extraction of the analytes in environmental water and plasma samples and the calculated relative recoveries were all >91%.

Analysis of diclofenac in water samples using in situ derivatization-vortex-assisted liquid-liquid microextraction with gas chromatography-mass spectrometry

A novel micro-extraction technique for a rapid and sensitive analysis of diclofenac (DCF) in water samples has been developed. DCF was derivatized and extracted simultaneously using vortex-assisted liquid-liquid micro-extraction (VALLME) prior to gas chromatography with mass spectrometry detection. The effects of extraction solvent volume, extraction and derivatization time and ionic strength of the sample were studied using 23 factorial experimental design. The optimum extraction conditions were as follows: 200 μL of chloroform, 25 μL of N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatization reagent, vortex extraction and derivatization time 5 min at 3000 rpm. The extraction recovery for different fortification levels was 98 %. Also, the proposed micro-extraction method exhibited results comparable with the solid phase extraction of real water samples. The proposed one-step VALLME and derivatization method is simpler and faster than the conventional extraction and derivatization methods used for the determination of DCF in real water samples.

Magnetic nanoparticles coated with ionic liquid for the extraction of endocrine disrupting compounds from waters

A hybrid nanomaterial was synthesized to be used in dispersive solid phase microextraction. It consist of a magnetic core (Fe3O4), obtained by coprecipitation covered by a silica (SiO2) layer were the ionic liquid methylimidazolium hexafluorophosphate (MIM-PF6) was attached. The Fe3O4@SiO2@MIM-PF6 nanoparticles have been characterized by microscopy and X-ray diffraction. The chemical composition of the hybrid nanoparticles has been studied by infrared spectroscopy and thermogravimetrical analyses. Finally, its potential in dispersive microextraction was evaluated for the isolation of 11 endocrine disrupting compounds (benzophenones, bisphenol A and parabens) from water samples.For this purpose, 10mg of the Fe3O4@SiO2@MIM-PF6 are added to 100mL of water sample (pH=8, NaCl 30% w/v) dispersed by ultrasound (1min) and vortex stirring (20min). Next, an external magnet is used to recover the MNPs. Later, the analytes are eluted from MNPs with 500μL of methanol under ultrasonic irradiation. 5μL of the extract is finally injected into a liquid chromatograph with tandem mass spectrometric detection (HPLC-MS/MS) for analytes separation and quantification.The proposed microextraction method allows the determination of the target compounds with limits of detection in the range from 0.16 to 1.21μg/L and the linearity was maintained between the limits of quantification and 500μg/L. The precision, expressed as relative standard deviation was better than 8.3%. The recovery study was performed on different water samples obtaining percentages higher than 87%, which demonstrated the applicability of the hybrid sorbent for the selected analytical problem. Moreover, the proposed method provides enrichment factors in the range from 15.4 to 49.2. Butylparaben, benzophenone 3 and benzophenone 6 were detected in the swimming pool water samples analyzed following the proposed microextraction method. The simultaneous presence of analytes from different endocrine disrupting families reveal the need for methodologies including a wider variety of compounds than those currently available.

Hollow‐fiber double‐solvent synergistic microextraction with high‐performance liquid chromatography for the determination of antitumor alkaloids in Coptis chinensis

A new hollow-fiber double-solvent synergistic microextraction method was proposed for the extraction and concentration of trace active compounds in traditional Chinese medicine. The main variables affecting the method were investigated and optimized. Under the optimized conditions, linearities were 0.01-10 μg/mL, detection limits were lower than 0.8 ng/mL, and interday, and intraday relative standard deviations were <9.20%. Furthermore, average recoveries ranged from 102.8 to 104.1%, and enrichment factors were 6-70 for the four alkaloids tested. The antitumor alkaloid group in Coptis chinensis was screened and identified by hollow-fiber cell fishing with high-performance liquid chromatography. The four alkaloids were then enriched and quantified by hollow-fiber double-solvent synergistic microextraction with high-performance liquid chromatography. The mechanism of the proposed microextraction method was described, and results demonstrated that the approach was a simple and reliable sample-preparation procedure. This method, as well as hollow-fiber cell fishing combined with high-performance liquid chromatography can be adopted to study the different characteristic effects of the multiple components and multiple targets of traditional Chinese medicine. The approach can also be used to conduct tailored quality control of the active compounds associated with therapeutic efficacy.

Analysis of ketoprofen enantiomers in human and rat plasma by hollow-fiber-based liquid-phase microextraction and chiral mobile-phase additive HPLC

A simple, inexpensive, and efficient preconcentration and cleanup three-phase hollow fiber liquid-phase microextraction method (HF-LPME) was developed for the extraction of the anti-inflammatory ketoprofen (KTP) from human and rat plasma and HPLC enantioseparation of its enantiomers using vancomycin as a chiral mobile-phase additive with an achiral C8 column. The effects of different parameters influencing the efficiency of extraction were optimized for aqueous samples. Under optimized conditions, KTP enantiomers were extracted from 0.5 mL of plasma diluted to 5 mL with salinated and acidified deionized water (pH = 2) with 25 μL of alkalinized acceptor phase (pH = 11) during 30 min at room temperature. The mean recoveries of (−)-(R)- and (+)-(S)-KTP were 72.8% and 70.9%, respectively. The quantification limit was 20 ng/mL with linear response over the 20–2000 ng/mL concentration range for both enantiomers. Assay precision was studied within-day and between-day using 100 ng/mL KTP solutions. For both KTP enantiomers, relative standard deviations were lower than 12%. The proposed microextraction method was applied for the extraction of KTP enantiomers from human and rat plasma samples after oral administration of pure (±)-KTP in 4 mg/kg dosage for rats and 50 mg dosage for humans to assess the enantiospecific bioavailability of KTP enantiomers in their plasma. In vivo inversion studies revealed that the bioavailability of S-KTP is higher than that of the R enantiomers in rat, but they are similar in human plasma. The developed method showed that HF-LPME is a promising technique for sample preparation for the analyses of chiral drugs in biological samples.

Sensitive determination of terazosin in pharmaceutical formulations and biological samples by ionic-liquid microextraction prior to spectrofluorimetry.

An efficient and environmentally friendly sample preparation method based on the application of hydrophobic 1-Hexylpyridinium hexafluorophosphate [Hpy][PF6] ionic liquid (IL) as a microextraction solvent was proposed to preconcentrate terazosin. The performance of the microextraction method was improved by introducing a common ion of pyridinium IL into the sample solution. Due to the presence of the common ion, the solubility of IL significantly decreased. As a result, the phase separation successfully occurred even at high ionic strength, and the volume of the settled IL-phase was not influenced by variations in the ionic strength (up to 30% w/v). After preconcentration step, the enriched phase was introduced to the spectrofluorimeter for the determination of terazosin. The obtained results revealed that this system did not suffer from the limitations of that in conventional ionic-liquid microextraction. Under optimum experimental conditions, the proposed method provided a limit of detection (LOD) of 0.027 μg L−1 and a relative standard deviation (R.S.D.) of 2.4%. The present method was successfully applied to terazosin determination in actual pharmaceutical formulations and biological samples. Considering the large variety of ionic liquids, the proposed microextraction method earns many merits, and will present a wide application in the future.

Carbon nanofibers extracted from soot as a sorbent for the determination of aromatic amines from wastewater effluent samples

The isolation and characterization of carbon nanofibers from soot obtained by burning natural oil is reported. The fibers were extracted from the soot with tetrahydrofuran followed by sonication. The carbon nanofibers were mixed with poly(vinyl alcohol) and electrospun to get the nanofiber mat. The extraction ability of electrospun nanofibers for the separation and preconcentration of aromatic compounds such as 3-nitroaniline, 4-chloroaniline, 4-bromoaniline and 3,4-dichloroaniline were tested and efficiently evaluated using high performance liquid chromatography. Under optimized conditions, the method showed good linearity in a range of 0.5–50 μg L −1 with correlation coefficient ranging from 0.989 to 0.998. High precision of the extraction with RSD values of 4.5–5.8% and low LOD value in a range of 0.009–0.081 μg L −1 for all aniline compounds were achieved. The proposed microextraction method offers advantages such as easy operation, high recovery, fast extraction, minimal use of organic solvent and elimination of tedious solvent evaporation and reconstitution steps.