Organic Solvent Consumption Research Articles

Preparation of hollow porous molecularly imprinted and aluminum(III) doped silica nanospheres for extraction of the drugs valsartan and losartan prior to their quantitation by HPLC.

Water compatible hollow porous molecularly imprinted nanospheres (HP-MINs) have been prepared for specific recognition and extraction of the blood pressure regulating drugs valsartan (VAL) and losartan (LOS). All synthetic steps were performed in aqueous medium and without consumption of organic solvents. The morphology and functionality of the materials were characterized by FT-IR, FE-SEM, and TEM techniques. The adsorption and selectivity experiments demonstrate that the HP-MINs possess a high binding capacity, fast kinetics, excellent water dispersibility and remarkable selectivity for VAL and LOS. The HP-MINs were utilized for dispersive solid phase extraction of VAL and LOS prior to their determination by HPLC-UV. Main variables and their interactions on extraction yield were optimized by multivariate analysis with least amount of experiments. Under optimized conditions, the method has a linear response in the 5-2000μgL-1 concentration range of both VAL and LOS. The limits of detection are 1.5μgL-1 for VAL and 1.4μgL-1 for LOS. Graphical abstract Schematic representation of dispersive solid phase extraction (d-SPE) of valsartan (VAL) and losartan (LOS) from urine sample by hollow porous molecularly imprinted nanospheres (HP-MINs).

Microbial Extraction of Berberine from Phellodendron for Simultaneous Product Purification and Waste Resource Utilization

Berberine (BBR) is a broad-spectrum antimicrobial agent extracted from plants. However, traditional extraction of BBR depends on the massive consumption of organic solvent, leading to serious environmental pollutions. Here, the authors established a novel microbial method for BBR extraction from pulverized Phellodendron. A microbial consortium consisting of three Bacillus bacteria was constructed based on cellulase enzyme activities. The three bacteria together showed high cellulase enzyme activities for plant cell wall degradation. Moreover, no BBR degradation was detected during the cultivation of each strain. After the cultivation of this Bacillus consortium and pulverized Phellodendron for 56 h, BBR was successfully extracted into the medium. More importantly, the by-products of extraction such as phellodendrine were efficiently dissimilated by bacteria during the extraction, and the peak area of BBR occupied more than 60% of the total in the end of fermentation. The determination of extraction waste indicated that less than 10% of BBR remained in the extraction residue. Finally, the extraction residue that contains Bacillus consortium was applied as fertilizer used in improving soil bacterial diversity. After the cultivation for 9 days, the amount of Bacillus genus in the soil was almost kept the same with initiation, meaning that Bacillus was colonized in the experimental soil. Overall, this is the first report on microbial extraction of chemicals from the plant, and this work provided a new way for resource re-utilization in the traditional Chinese medicine extraction industry.

Rapid Determination of Resveratrol and Piceid in Wine by High-Performance Liquid Chromatography

In this study, a solid-phase extraction column dedicated to the detection of resveratrol was directly used for purification after adjusting the pH of the sample, without resorting to a new method for sample extraction. The compounds cis-resveratrol, trans-resveratrol, cis-piceid, and trans-piceid were thus detected in wine simultaneously by high-performance liquid chromatography (HPLC). This method offers rapid and easy operation and involves low consumption of organic solvents, paving the way for efficient determination of the variety and other parameters of grapes used in wine samples..

Sensitive Determination of Semicarbazide in Flour by Differential Pulse Voltammetry

A sensitive method for semicarbazide determination was developed by differential pulse voltammetry. Comparing to traditional methods, such as HPLC‒mass spectrometry and HPLC–fluorescence detection, it provides several advantages including using low consumption of organic solvents and low cost of analysis. Accordingly, 2-nitrobenzaldehyde was used as an active reagent to react with semicarbazide. The reaction product, 2-nitrobenzaldehyde semicarbazone (2-NSEM), was quantified by differential pulse voltammetry. A linear relationship was obtained between the peak current and 2-NSEM concentration in the range from 0 to 100 μg/L (R2 = 0.999). The limit of detection (LOD) was calculated to be 3 μg/kg (signal to noise ratio of 3), which is lower than LOD obtained by direct differential pulse voltammetry determination of semicarbazide. The developed method was successfully applied to determine semicarbazide in flour samples with satisfactory recoveries from 92 to 99% (relative standard deviation < 4.3%, n = 6) indicating this method to be potential and valuable for semicarbazide detection.

Organic solvent-saving preparation of water glass based aerogel granules under ambient pressure drying

An organic solvent-saving method of preparing silica aerogel is reported. The silica aerogel was made from water glass (WG) and used as the solvent. Na+ was removed through ion exchange; prior to this ion exchange, concentrated hydrochloric acid (HCl) was added to the WG solution. The sol pH was adjusted to ~1 to suppress the condensation to the maximum extent. Ethanol was added to the sol after ion exchange. Surface modification was conducted with the assistance of hexamethyldisiloxane, which was catalyzed by HCl. The entire process can be finished in 6 h. The overall consumption of organic solvent is much lower than that in the previous preparation route. Characterization results indicate that the resulted silica aerogel has a uniform mesoporous structure and low thermal conductivity (0.0237–0.0245 W/m·K at 1 atm).

Synthesis of Octyl-Quaternary Ammonium Mixed-Mode Stationary Phase by Vapor Deposition Approach and Its Application in Compound Preparation Separation

An octyl-quaternary ammonium (Sil-C8-QA)-modified silica stationary phase was prepared by a two-step vapor deposition method which can substantially reduce the consumption of toxic organic solvents. The structure of the dual-functional ligands stationary phase was characterized by Fourier transform infrared spectroscopy and solid-state 13C CP/MAS NMR. Following elemental analysis, the surface density of octyl and quaternary ammonium bonding amount is 2.13 µmol m−2 and 0.77 µmol m−2, respectively. The efficiency and selectivity of the two-ligand phases were compared with two sole functional ligand phases: quaternary ammonium (Sil-QA)- and octyl-modified silica (Sil-C8). Chromatographic evaluation demonstrated a mixed-mode reversed-phase/anion-exchange retention property on the Sil-C8-QA column. The retention behavior of a homologous series of alkylbenzoic acids on the synthesized phase was systematically studied by changing the pH, ionic, and solvent strength of the mobile phase. A well-established mixed-model mechanism was confirmed. The Sil-C8-QA phase can predominantly enhance the retention of acidic drugs and improve their selectivity. It was also successfully applied to the simultaneous separation and determination of three kinds of compound preparations with large differences in component polarity.

Method Validation for Simultaneous Quantification of Olmesartan and Hydrochlorothiazide in Human Plasma Using LC-MS/MS and Its Application Through Bioequivalence Study in Healthy Volunteers.

A new, simple, sensitive, selective, rapid, and high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for simultaneous quantification of Olmesartan and hydrochlorothiazide in human plasma. Simple liquid–liquid extraction procedure was applied for plasma sample pretreatment using a mixture of diethyl ether and dichloromethane, as an extraction solution. Analytes were separated on UNISOL C18 150*4.6 mm, 5 µm column using methanol, and 2 mM ammonium acetate pH 5.5 (80:20, v/v) as a mobile phase and detected by electrospray ionization in the multiple reaction monitoring (MRM) mode. The mass transition ion pairs were followed in negative ion mode as m/z 445.20 → 148.90 for Olmesartan; m/z 451.40 → 154.30 for Olmesartan D6 and m/z 295.80 → 205.10 for hydrochlorothiazide; m/z 298.90 → 206.30 for hydrochlorothiazide 13C D2. The method showed excellent linearity (r 2 > 0.99) over the concentration range of 5.002–2,599.934 ng/ml for Olmesartan and from 3.005 to 499.994 ng/ml for hydrochlorothiazide. Precision (% CV) and accuracy (% bias) for Olmesartan were found in the range of 3.07–9.02% and −5.00–0.00%, respectively. Precision (% CV) and accuracy (% bias) for hydrochlorothiazide were found in the range of 3.32–8.21% and 1.99–3.80%, respectively. This as developed novel and high-throughput liquid–liquid extraction bioanalytical method has substantial innovative value with the benefits of cost effectiveness, good extraction efficiency, shorter analysis run time, low organic solvent consumption, and simpler procedure over the previously reported solid-phase extraction method. The application of this method in pharmacokinetic studies was further demonstrated successfully through a bioequivalence study conducted on healthy human subjects, following oral administration of combined formulation of Olmesartan medoxomil and hydrochlorothiazide in fixed-dose tablet.

Online clean-up setup for the determination of non-fluorescent acidic pharmaceutical drugs in complex biological samples

Analysis of acidic pharmaceuticals in complex biological samples is a challenging and formidable task due to the existence of interfering constituents within the sample matrices. Therefore, in order to avoid analytical column clogging and suppression/enhancement of signals of the analyte of interest, herein a simple, cost-effective and quick online ion chromatography based clean-up setup was introduced. This system was further coupled with a cost-effective homemade photochemically induced fluorimetric (PIF) setup for direct online conversion of non-fluorescent acidic pharmaceutical drugs into their respective fluorescent species. This advantageous system was favorably applied for the determination of four non-fluorescent acidic compounds in two complex biological samples (human serum and oral fluid) with minimum labor and organic solvent consumption. At optimized conditions, the developed method has shown good sensitivity, selectivity, satisfactory recoveries (88.68–102.14%) and low limits of detection (0.35–8.10 μg/L) with minimum or zero matrix effect.

Sugaring-out assisted liquid-liquid extraction coupled with high performance liquid chromatography-electrochemical detection for the determination of 17 phenolic compounds in honey

In this work, a simple sugaring-out assisted liquid-liquid extraction (SULLE) method coupled with high performance liquid chromatography-electrochemical detection (HPLC-ECD) has been developed for rapid and sensitive determination of 17 phenolic compounds in honey. To achieve the maximum extraction efficiency of target analytes, several parameters, such as pH, ionic strength, extraction times and the volume of extracting solvent were optimized. Chromatographic separation was performed on a C18 column with a gradient methanol/aqueous formic acid elution, and the ECD was set at 1.0 V in oxidative mode. Under the optimal conditions, good linearity was obtained for 17 phenolic compounds with the coefficients of determination (R2) higher than 0.9986 in the range of 0.05–20 μg mL–1. The limits of detection (LODs, S/N = 3) for the 17 phenolic compounds were in the range of 0.20–1.26 μg kg–1 by ECD, 9–83 times lower than those obtained with UV detection. Satisfactory recoveries between 79.8% and 105.7% were obtained for spiked honey samples with relative standard deviations (RSD) less than 5.1%. Compared with conventional LLE method, the proposed SULLE method provided higher extraction efficiency and had advantages of rapidity, ease of operation, much less consumption of organic solvents and samples. The proposed HPLC-ECD method featuring excellent sensitivity and selectivity has been applied to the quantification of phenolic compounds in honey samples of different floral origin.

Liquid-phase microextraction in 96-well plates - calibration and accurate quantification of pharmaceuticals in human plasma samples

The use of miniaturized systems with the possibility for automation has become increasingly popular in the field of bioanalysis. As a new approach to liquid phase microextraction in the 96-well format, parallel artificial liquid membrane extraction (PALME) was introduced in 2013. In the present work, the reliability of the quantitative data obtained with PALME was thoroughly evaluated. Amitriptyline, nortriptyline, quetiapine, venlafaxine, o-desmethylvenlafaxine, and fluoxetine were selected as model analytes. The analytes were extracted under non-exhaustive conditions from human plasma samples and the extracts were analyzed directly by LC-MS/MS. Accuracy was within ±15% and precision was <15% when the QC samples were prepared in both pooled plasma and in plasma from multiple sources. Accuracy and precision was superior when stable isotopically labelled (SIL) internal standards were used, as compared to structural analogue internal standards in the plasma samples from multiple sources. SIL internal standards are therefore recommended as the first choice. Assessment of accuracy and precision was also carried out with four different operators performing the extraction procedure, providing accuracy within ±15% and precision <15%. The extraction recoveries were in the range from 48 to 85 %, and non-exhaustive extraction of the analytes did not affect the accuracy and precision of the method. With the method described, up to 96 samples can be extracted with a total extraction time of 60 min and with a total consumption of organic solvent less than 0.4 mL for the whole wellplate. PALME is therefore a new approach to high-throughput sample preparation, providing accurate quantification, along with simple workflow, low consumption of organic solvent, and extensive sample clean-up.

Fabric phase sorptive extraction for simultaneous observation of four penicillin antibiotics from human blood serum prior to high performance liquid chromatography and photo-diode array detection

Fabric phase sorptive extraction (FPSE), a current and up-to-date technique of solid sorbent-based microextraction, is regarded to be the basis of the development and advancement of an environmentally friendly, simple, sensitive, trustworthy, and fast analytical method by making use of high performance liquid chromatography and photo-diode array detection (HPLC-PDA) for the concurrent determination of four penicillin antibiotics residues (benzylpenicillin, cloxacillin, dicloxacillin and oxacillin) in human blood serum. By means of FPSE, the sophisticated material properties of sol-gel derived extraction and microextraction sorbents and the rich surface chemistry of an inherent porous and hydrophilic cellulose fabric substrate are successfully combined, leading to a flexible microextraction device which is characterized by high efficiency in extracting target analytes directly from complex sample matrices. Solvent evaporation and reconstitution steps, which are considered to be rather time-consuming, were eradicated successfully from the sample preparation workflow, organic solvent consumption was brought to a minimum while protein precipitation was assessed as impractical. Thus, FPSE complies with all green analytical chemistry (GAC) criteria. The microextraction device is characterized by a very high chemical and solvent stability owing to the strong chemical bonds formed between the sol–gel sorbent and the substrate. Thus, any organic solvent/solvent mixture can serve as the eluent/back-extraction solvent. Herein, sol-gel poly(tetrahydrofuran) coated FPSE membrane provided optimum extraction sensitivity for the selected penicillin antibiotics, which were analyzed using an RP-HPLC method, validated in terms of sensitivity, linearity, accuracy, precision, and selectivity. For all four penicillin antibiotics, the limit of detection and the limit of quantitation were 0.15 ng/μL and 0.5 ng/μL, respectively.

Isocratic micellar liquid chromatography using mixed anionic and non-ionic surfactants as mobile phase additives for separation of 17 free amino acids

In this work, an isocratic micellar chromatographic method for separation of 17 free amino acids was first established. Mixed anionic and non-ionic surfactants were used as mobile phase additives. Besides, a chromatographic environment was simulated and the possible mechanism was discussed. Pre-column derivatization with 9-fluorenylmethyl chloroformate was used before chromatographic analysis. The optimized chromatographic conditions were the mobile phase A (0.075 M sodium dodecyl sulfate solutions and 0.010 M polyoxyethylene lauryl ether containing 20 mM ammonium acetate at pH 3.5) and B (100% acetonitrile) (85:15, v/v) running at 1.2 mL/min by a Venusil XBP C18 column (5 µm, 250 × 4.6 mm) at 35.0 °C. Compared with the conventional reversed phase liquid chromatography, the consumption of organic solvent in the method is lower which reduces the analysis cost and being environment-friendly. In addition, complex gradient elution is not required. This provides an alternative way for the separation of amino acids.

New approach for sample clean-up using microextraction by packed sorbent to determine methadone and EDDP in hair samples

This work describes the development and validation of a novel analytical method for the simultaneous determination of methadone and the main metabolite (EDDP) in hair samples by gas chromatography-tandem mass spectrometry (GC-MS/MS) using microextraction by packed sorbent (MEPS), a miniaturized SPE approach, for sample clean-up. Previously washed hair samples were cut into small fragments and 50 mg was weighed into glass tubes. One mL of 1 M sodium hydroxide was added, and incubation took place at 50 °C for 45 min. The extracts were centrifuged at 3500 rpm (15 min), were mixed with 1 mL of 2% formic acid, and 20 μL of internal standards working solution was added. The steps for sample clean-up were previously optimized, and the final conditions were as follows: conditioning (3 cycles of 250 μL of methanol and 3 cycles of 250 μL formic acid 2%); sample load (9 cycles of 250 μL); wash (150 μL of 3.36% formic acid); and elution (6 cycles of 100 μL of ammonium hydroxide 2.36% (in methanol). The extracts were evaporated to dryness under a gentle nitrogen stream, and were afterwards dissolved in 50 μL of methanol, from which 2 μL was injected in the chromatographic system (GC-MS/MS). The method was validated following the standards of the Food and Drug Administration and the Scientific Working Group of Forensic Toxicology. The studied parameters included selectivity, calibration model and linearity, limit of detection and limit of quantification, precision, accuracy and recovery. Linearity was obtained from the lower limit of quantitation (LLOQ) up to 30 ng/mg, with all target compounds revealing determination coefficients greater than 0.99. The LLOQs were 0.025 ng/mg, and recoveries around 60% were obtained for both compounds. Precision and accuracy were acceptable, namely coefficients of variation typically below 15% and relative errors within a ± 15% interval from the nominal concentration were obtained. The obtained limits can be considered quite satisfactory, especially when compared to the available literature on the subject. Many authors adopt hair incubation as a unique sample preparation procedure, not considering the additional clean-up of the resultant extract. This results in lower losses of the analytes, but also in dirtier extracts, hence compromising chromatographic analysis. For this reason, SPE is a traditional and widely implemented clean-up procedure for hair specimens, however the great volumes of organic solvents usually required with this technique might be considered a disadvantage. A miniaturized procedure is described to pre-concentrate methadone from hair samples by means of solid-phase microextraction (SPME) [1] , however presenting higher LOQ. MEPS is a good alternative to classical clean-up procedures, with low consumption of organic solvents, also allowing the re-utilization of the sorbent (over 100 extractions are possible using the same cartridge) and thus reducing the cost per analysis. It is noteworthy that this is the first time that the combination of MEPS and GC-MS/MS is used for the determination of these compounds in hair, making it an advantageous tool for their screening in clinical and forensic scenarios.

Developing and Validating a UPLC-MS Method with a StageTip-Based Extraction for the Biogenic Amines Analysis in Fish.

To effectively extract biogenic amines (BAs) from complex food matrices is an important issue. In this study, a stop-and-go-extraction tip (StageTip)-based method for simultaneous enrichment of six BAs including histamine, tyramine, putrescine, cadaverine, tryptamine, and β-phenylethylamine in fish samples was developed and optimized. This StageTip-based BAs extraction method required short extraction time, small sample size, and minimal consumption of organic solvents. In addition, an ultrahigh-performance liquid chromatography coupled with triple quadrupole mass spectrometer was used to identify and quantify BAs without derivatization. Target recovery efficiencies of BAs from spiked fish samples ranged from 84% to 110%. Linear regression models were established to determine BAs in the range of 0.4 to 3.0 mg/L (R2 > 0.995). Good repeatability was obtained with relative standard deviation of peak areas (1.17 to 5.61%) and retention time (0.09 to 0.20%). High sensitivity was achieved for the detection of six BAs (0.064 to 1.00 ng/L for the limit of detection, 0.10 to 5 ng/L for the limit of quantification). The proposed method had an obvious advantage in the analysis of BAs in complex food matrices such as fish tissues since it could reflect the subtle distribution of BAs from one fish fillet. PRACTICAL APPLICATION: A StageTip-based BAs enrichment combined with UPLC-MS analysis method was developed and optimized, which was low-cost, environmentally friendly, and with good analytical performances. As such, it has the potential to become a powerful tool for the analysis of BAs in different complex food matrices.

Simultaneous and fast determination of bisphenol A and diphenyl carbonate in polycarbonate plastics by using excitation-emission matrix fluorescence couples with second-order calibration method.

A new strategy for the determination of bisphenol A (BPA) and diphenyl carbonate (DPC) in polycarbonate plastics has been proposed, combing excitation-emission matrix fluorescence and second-order chemometrics methods. The studied compounds are two of the most frequently used chemical raw materials and intermediates, which is mainly used for bio-chemical products. The method is fast and sensitive as it can avoid tedious pretreatment steps and large amounts of organic solvents consumption. Chemometrics allowed accurate and precise quantification of two target analytes even in the presence of severe spectral overlap, unknown and background interferences, which benefit from "second-order advantages" provided by chemometrics multivariate calibration. Reasonable quantification results were obtained in real plastics samples, with limits of detection for two analytes were 0.04 and 1.18 × 103 ng mL-1 and limits of quantitation were 0.11 and 3.58 × 103 ng mL-1. In addition, the average recoveries for BPA and DPC were 99.35% and 83.50% with relative standard deviation <2.30%. It was proved that the proposed method can be a useful and sensitive tool to the determination of BPA and DPC in different polycarbonate plastics with a simple sample pretreatment at low cost.

The possibility to use multi-walled carbon nanotubes as a sorbent for dispersive solid phase extraction of selected pharmaceuticals and their metabolites: Effect of extraction condition

This article presents a dispersive solid phase extraction (dSPE) method combined with liquid chromatography-chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) for the simultaneous isolation and quantification of eight pharmaceuticals and their selected metabolites (metronidazole, sulfamethoxazole, N-acetylsulfamethoxazole, diclofenac, 4-hydroxydiclofenac, 5-hydroxydiclofenac, naproxen and 6-O-desmethylnaproxen) in environmental water samples. Interestingly, in the developed method, multi-walled carbon nanotubes (MWCNTs) were used as a sorbent due to their extraordinary sorption capacity. Key parameters that influence the efficiency of the analytical extraction procedure, such as the type and amount of sorbent, the pH of the sample solution and the composition and volume of the elution solvent have been determined. Significant differences in sorption affinity were observed depending on the pH of the sample. To explain these differences, a computational study was carried out to examine the effect of environmental conditions (different pH levels) on the geometry of the structures sulfamethoxazole, N-acetylsulfamethoxazole, diclofenac (described by the variety of structural properties). It is worth noting that only 4 mg of CNTs (with outer diameter < 8 nm) allowed to achieve 100% sorption for all target analytes. The analytes were eluted with 10 mL of a mixture of ACN:CH3COOH (3:7, v/v). Under the optimal conditions, detection limits and linearity were achieved in the range of 0.01–0.08 μg L−1 and 0.02–2.5 μg L−1, respectively. The application potential of the developed methodology for the effective extraction of eight pharmaceuticals from surface and waste water samples was assessed by determining the matrix effects. The developed extraction technique can be considered as a “green”, mainly due to very low consumption of organic solvent and solid sorbent, fast and low-labor procedure, and the possibility of reuse of the sorbent.

Aiming for a standardized protocol for preparing a process green synthesis report and for ranking multiple synthesis plans to a common target product

Abstract This paper proposes a standardized format for the preparation of process green synthesis reports that can be applied to chemical syntheses of active pharmaceutical ingredients (APIs) of importance to the pharmaceutical industry. Such a report is comprised of the following eight sections: a synthesis scheme, a synthesis tree, radial pentagons and step E-factor breakdowns for each reaction step, a tabular summary of key material efficiency step and overall metrics for a synthesis plan, a mass process block diagram, an energy consumption audit based on heating and cooling reaction and auxiliary solvents, a summary of environmental and safety-hazard impacts based on organic solvent consumption using the Rowan solvent greenness index, and a cycle time process schedule. Illustrative examples of process green synthesis reports are given for the following pharmaceuticals: 5-HT2B and 5-HT7 receptors antagonist (Astellas Pharma), brivanib (Bristol-Myers Squibb), and orexin receptor agonist (Merck). Methods of ranking synthesis plans to a common target product are also discussed using 6 industrial synthesis plans of apixaban (Bristol-Myers Squibb) as a working example. The Borda count method is suggested as a facile and reliable computational method for ranking multiple synthesis plans to a common target product using the following 4 attributes obtained from a process green synthesis report: process mass intensity, mass of sacrificial reagents used per kg of product, input enthalpic energy for solvents, and Rowan solvent greenness index for organic solvents.

Determination of Tetracycline in Water and Honey by Iron(II, III)/Aptamer-Based Magnetic Solid-Phase Extraction with High-Performance Liquid Chromatography Analysis

A novel aptamer-based adsorbent was prepared for the magnetic solid-phase extraction of tetracycline. The Fe3O4/aptamer adsorbent was fabricated by immobilizing an aptamer on the surface of Fe3O4 magnetic nanoparticles by the reaction between avidin and biotin. The parameters affecting the isolation efficiency such as the pH, extraction time, extraction temperature, eluent, and elution time were investigated in detail. Under the optimal conditions, a linear relationship between the peak area and the concentration of tetracycline was observed in the range from 10.0 to 3000.0 µg L−1 with a correlation coefficient of 0.9985 and a limit of detection of 2.5 µg L−1. The developed method was successfully employed for the determination of tetracycline in honey and water samples with recovery values from 82.9 to 107.3% and relative standard deviations less than 7.6%. Compared with previously reported methods for the determination of tetracycline, the proposed protocol provides improvements in the limit of detection and specificity with reduced consumption of adsorbent and organic solvents.

In-line coupling of supported liquid membrane extraction across nanofibrous membrane to capillary electrophoresis for analysis of basic drugs from undiluted body fluids.

Planar polyamide 6 nanofibrous membrane was for the first time used in direct coupling of supported liquid membrane (SLM) extraction to CE analysis. Disposable microextraction device with the nanofibrous membrane was preassembled and stored for immediate use. The membrane in the device was impregnated with 1 µL of 1-ethyl-2-nitrobenzene and the device was subsequently filled with 10 µL of acceptor solution (10 mM HCl) and 15 µL of donor solution (sample). The device was in-line coupled to CE system for selective extraction and direct injection, separation and quantification of model basic drugs (nortriptyline, haloperidol, loperamide and papaverine) from standard saline solutions (150mM NaCl) and from undiluted human body fluids (urine and blood plasma). Compared to standard polypropylene supporting material, the nanofibrous membrane demonstrated superior characteristics in terms of lower consumption of organic solvents, constant volumes of operational solutions, full transparency and possibility to preassemble the devices. Extraction parameters were better or comparable for the nanofibrous vs. the polypropylene membrane and the hyphenated SLM-CE method with the nanofibrous membrane was characterized by good repeatability (RSD ≤ 11.3%), linearity (r2 ≥ 0.9953; 0.5-20mg/L), sensitivity (LOD ≤ 0.4mg/L) and transfer (27-126%) of the basic drugs.

Extraction of colchicine from Gloriosa superba tubers: a comparison of conventional and microwave-assisted extraction

The present work envisages assessment of microwave assisted extraction (MAE) followed by comparison with that of conventional methods for effective extraction of colchicine from Gloriosa superba tubers. Subsequently, optimum conditions for MAE were determined using response surface methodology by employing Box-Behnken design. The observed optimal conditions for efficient extraction of colchicine using microwave were 15 min, 245 W and 100% methanol which showed 0.64% colchicine as compared to conventional with 0.48% by heat reflux extraction. Assessment of extraction techniques revealed that significant amount of time and energy could be saved using MAE, whilst lesser amount of organic solvent consumption showed an eco-friendly nature.