Extraction Techniques For Analysis Research Articles

Isobar-free neon isotope measurements of flux-fused potential reference minerals on a Helix-MC-Plus10K mass spectrometer

This work presents new analytical techniques for extraction and analysis of neon from a suite of different mineral phases, including quartz, pyroxene, hematite, apatite, zircon, topaz, and fluorite. Neon was quantitatively extracted at 1100 °C from all of these minerals using an in-vacuum lithium borate-flux fusion technique. Evolved neon was purified using a cryogenic method capable of separating Ne from He present in abundances ~8 orders of magnitude higher, typical of samples carrying nucleogenic/radiogenic noble gases. The purified neon was measured on a Helix-MC-Plus10K mass spectrometer that permits isobar-free measurement of all three neon isotopes. When operated at its highest mass resolving power (MRP) of ~10,300, the shoulder representing solely 22Ne on the low mass-side of the 22Ne-CO2+2 doublet is wide enough to permit measurement of isobar free 22Ne. Operating in this mode comes with the penalty of a 50% reduction in neon sensitivity. Coupled with a mathematical isobar-stripping method, this approach excludes 99.5% of the CO2+2 while still collecting >99% of the 22Ne beam. Routine edge-centering on the dynamic CO2+2 peak prior to introduction of a sample permits rapid and robust relocation of the desired measure point in the mass spectrum.Cosmogenic 21Ne and 22Ne concentrations obtained using these methods on the Cronus-A quartz and Cronus-P pyroxene international reference materials are in excellent agreement with previous work or expectations. Similarly, the concentration of nucleogenic 21Ne and 22Ne in Durango apatite and the CIT hematite standard agree well with previous work. Durango apatite has notable heterogeneity in neon concentrations, consistent with previous observations of heterogeneous He, U and Th concentrations in this apatite. Nucleogenic neon concentrations are also presented for previously unstudied minerals including a Sri Lanka zircon (SLC), a topaz from the Imperial Topaz mine in Brazil (ITP1), and a fluorite (W-90) from New Hampshire. Taken together this set of potential reference minerals and the associated dataset provide a starting point for intercalibration among multiple mineral phases carrying 21Ne and 22Ne of cosmogenic or nucleogenic origin.

Recent applications of on-line supercritical fluid extraction coupled to advanced analytical techniques for compounds extraction and identification.

In a previous review (Sánchez-Camargo etal., J. Sep. Sci. 40 (2017) 213-227), we discussed the application of on-line supercritical fluid extraction coupled to chromatographic techniques. This review includes an update of the most recent publications (from January 2016 till June 2018) on this topic, which employs advanced analytical techniques for extracting and identifying valuable analytes. Supercritical fluid extraction has been widely recognized as a green sample preparation technique, because it is efficient, environmentally friendly, powerful, and faster, offering the possibility of direct coupling to analytical instrumental techniques. Among those techniques, supercritical fluid chromatography has experienced an innovative progression in the last 10 years, and the most recent applications of supercritical fluid extraction are coupled to this advanced analytical tool. The general principles, both methodological and instrumental of on-line supercritical fluid extraction coupled to supercritical fluid chromatography are described here. Besides, applications of the mentioned coupling for analysing biological fluids, food, soil, and botanical samples are also presented and discussed. Finally, a brief description about the very recent on-line coupling of supercritical fluid extraction to ion mobility spectrometry is presented, as well as concluding remarks about the importance of using these coupled techniques in the near future.

Detection of cathinone and mephedrone in plasma by LC-MS/MS using standard addition quantification technique

BackgroundCathinones better known as bath salts have been listed as illicit drugs since 2011. Few studies have focused on the analytical extraction techniques and the matrix effect affecting their detection and quantification in biological samples. Matrix suppression of the signal of cathinones has been previously observed in urine sample by LC-MS/MS. This study is aimed to use the standard addition method to overcome the plasma matrix effect on the quantification of cathinone and mephedrone by LC-MS/MS.FindingsThe results showed the matrix effect for cathinone at lowest tested concentration (10 ng/ml) was significantly reduced from 210.9 to 133.7%, but not for mephedrone (from 196.8 to 191.9%) by using standard addition method. At the higher tested concentrations of samples, the matrix effects were significantly reduced for both cathinone and mephedrone by using standard addition technique.ConclusionsStandard addition quantitative technique can serve as an alternative quantitative method for LC-MS/MS when suitable internal standards are not available.

Optimized Analytical Techniques for Extraction and Separation of Bioactive Compounds from Diverse Plant Types

Bioactive compounds (BACs) from plants provide unlimited opportunities for pharmaceuticals and natural agrochemicals development due to vast diversity of secondary compounds. Successful identification and development of natural products from plants necessitates a standard and integrated approach to screen compounds which aids in determination of dose response activity. We examined Peperomia pellucida (herb with fibrous root), Cleome viscosa (herb with tap root), Piper chaba (climber) and Artocarpus lakoocha (tree). In C. viscosa plants, BACs were collected from ‘Root Exudates Trapping System’ made of Buchner funnel and conical flask, while compounds were collected from P. pellucida by a self-designed horizontal tube like glass ware with stopper and funnel at either end. BACs are extracted from stem and leaves dust of P. chaba and A. lakoocha respectively. The basic sequential steps are same included grinding of plant parts, homogenization, vacuum filtration followed by liquid-liquid extraction in which BACs were fractionated into two major phases (ethyl acetate layer and aqueous layer). The extracts were further purified into a single pure compound by repetitive running through column and subsequently followed by thin layer chromatography and finally subjected to spectral analyses (viz. MS, IR, 1HNMR and 13CNMR) for complete molecular characterization. A new Phenol glycoside was isolated from Peperomia pellucida and Lactam nonanoic acid was recovered from Cleome viscosa. Four major compounds were recovered from Piper chaba and Artocarpus lakoocha with remarkable bioactivity but only the important fractions are described here. These new extraction techniques will extend and enhance the usefulness of plants as renewable resources of valuable chemicals.

Comparison of extraction techniques for quantitative analysis of pendimethalin from soil and rice grain

ABSTRACTThe paper exploits the development, optimization, and comparison of fast, efficient, quantitative analytical extraction techniques such as ultrasonic-assisted extraction (UAE) and matrix solid-phase dispersion (MSPD) for proficient extraction of pendimethalin from soil and rice samples. Residues of pendimethalin were quantified using high-performance liquid chromatography. Impact of several experimental parameters of UAE and MSPD techniques on extraction of pendimethalin from soil and rice samples was also evaluated. Under the optimized conditions, the mean percent recoveries obtained from both methods were in the range of 80.3–101.3 and 81.7–103.1, respectively, with relative standard deviation <10. Linearity was in the range of 0.003–5.0 µg mL−1 with limit of detection and limit of quantification as 0.001 and 0.003 µg g−1, respectively. MSPD method was found superior in terms of low solvent consumption, small sample size, and reduced matrix coextracts due to simultaneous extraction and cleanup steps. Both extraction methodologies were successfully applied in monitoring routine soil and rice samples, in which pendimethalin residues (0.003–0.007 µg g−1) were detected in few rice samples while residues in soil samples were below the quantification limit.

Wideband analytical extraction technique of π‐equivalent circuit model for Si/SiGe heterojunction bipolar transistor in BICMOS process

A developed analytical extraction technique of small-signal -topology equivalent circuit model for Si/SiGe heterojunction bipolar transistor is presented. The intrinsic model parameters, including base resistance (Rb) which are difficult to extract in the previous works, are analytically extracted by utilising a novel set of exact equations that do not need any numerical fitting, special polarisation of the device or any kind of post processing. Moreover, the substrate effect and the distributed base-collector junction are accurately modelled and extracted. To the authors knowledge, the extracted values using the presented methodology exhibit flattest and widest frequency independent behaviour among all those extracted with earlier published analytical techniques, especially for base resistance. Excellent agreement is noted between the S-parameters measurements and their simulated counterpart using the extracted model in the frequency range from 40 MHz-40 GHz at different bias conditions.

Application of gas-diffusion microextraction for high-performance liquid chromatographic analysis of aliphatic amines in fermented beverages

This work presents a novel application of a recently developed analytical extraction technique, gas-diffusion microextraction (GDME), in the analysis of three volatile aliphatic amines (methylamine, dimethylamine and ethylamine) in fermented beverages. The method involves the extraction of the amines using GDME and pre-column derivatisation of the collected amines with phenyl isothiocyanate (PITC) followed by analysis by high-performance liquid chromatography with UV detection. It was successfully applied to quantify the mentioned amines in Portuguese wines (white, red and rosé) and beers (dark, pilsner and alcohol-free). Limits of detection ranged between 12 and 46 μg L−1 and limits of quantification between 39 and 153 μg L−1. This method is shown to be a competitive alternative to existing methods since it accomplishes a great simplification in the sample preparation needed.

Improved Analytical Extraction and Clean-up Techniques for the Determination of PAHs in Contaminated Soil Samples

Development and optimisation of fast, efficient, quantitative, economic and environmentally friendly analytical extraction techniques for the extraction clean up, and pre-concentration in the quantification of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in contaminated soils have been carried out. Three different extraction methods (Soxhlet, ultra sonication and mechanical shaking) were investigated on a low-level PAH soil certified reference material (CRM131-100) and the results were compared to determine the technique with the highest extraction efficiency. The clean up and pre-concentration procedures were optimized using both the conventional method (i.e. column packing with silica gel) as well as the solid phase extraction (SPE). Chromatographic conditions for the separation of PAHs using High Performance Liquid Chromatography (HPLC) using UV-DAD and fluorimetric detection with programmed excitation and emission wavelengths were also optimized. Six different extraction solvents: acetone, cyclohexane, 2- propanol, methanol, acetonitrile and dichloromethane, were tested to select the most suitable solvent for the extraction of the 16 PAHs from the certified soil reference material. Acetonitrile, dichloromethane and tetrahydrofuran were also tested as eluants for the optimisation of SPE clean up. The optimized ultrasonic extraction procedure utilizing four 15 minutes extraction cycles at 50 oC and SPE clean up with tetrahydrofuran: acetonitrile (1:1) and subsequent separation by gradient reversed phase HPLC with fluorimetric detection extracted the PAHs from the certified reference material with recoveries ranging from 63.6 % to over 100 % .

Extraction Techniques for Polycyclic Aromatic Hydrocarbons in Soils

This paper aims to provide a review of the analytical extraction techniques for polycyclic aromatic hydrocarbons (PAHs) in soils. The extraction technologies described here include Soxhlet extraction, ultrasonic and mechanical agitation, accelerated solvent extraction, supercritical and subcritical fluid extraction, microwave-assisted extraction, solid phase extraction and microextraction, thermal desorption and flash pyrolysis, as well as fluidised-bed extraction. The influencing factors in the extraction of PAHs from soil such as temperature, type of solvent, soil moisture, and other soil characteristics are also discussed. The paper concludes with a review of the models used to describe the kinetics of PAH desorption from soils during solvent extraction.

Silicone rod extraction of pharmaceuticals from water

Silicone elastomer (in the form of a flexible rod) is one of the materials currently tested for use in analytical extraction techniques and passive sampling devices. We investigated the applicability of this material for the enrichment of selected polar pharmaceuticals (antipyrine, carbamazepine, diclofenac, ibuprofen, bezafibrate) from water. Time-resolved batch extraction tests (up to five weeks in duration) were performed in stirred water samples ( approximately 0.5 L) with 2-cm-long silicone rod pieces. After re-extraction of trapped compounds with methanol, analysis was performed using liquid chromatography coupled with mass spectrometry. Distribution equilibrium was reached after a test duration of seven days. The silicone rod/water partition coefficients of the investigated pharmaceuticals range from 4 (antipyrine) to 1250 (diclofenac), and are related to the hydrophobicity of the compound. Enrichment of these pharmaceuticals in the silicone rod is lower than for other compound classes (chlorinated and polycyclic hydrocarbons).

Comparison of Solid-Phase Microextraction, Supercritical Fluid Extraction, Steam Distillation, and Solvent Extraction Techniques for Analysis of Volatile Consituents in Fructus Amomi

Four sampling techniques, solid-phase microextraction (SPME), supercritical fluid extraction (SFE), steam distillation (SD), and solvent extraction (SE), were compared for the analysis of volatile constituents from a traditional Chinese medicine (TCM) of the dried ripe fruit of Fructus Amomi (Sha Ren). A total of 38 compounds were identified by gas chromatography/mass spectrometry. Different SFE and SPME parameters (modifier content, extraction pressure, and temperature for SFE and fibers, extraction temperature, and time for SPME) were studied. The results by SFE and SPME were compared with those obtained by conventional SD and SE methods. The results showed that SFE and SPME are better sample preparation techniques than SD and SE. Due to SFE's requirement for expensive specialized instrumentation, the simplicity, low cost, and speed of SPME make it a more appropriate technique for extraction of volatile constituents in TCMs.

Geological analysis of acoustic subbottom profiles as a tool for prediction of acoustic property distribution

Geoscientists have developed analytical techniques for extraction of geologic and acoustic data from acoustic profiles as well as prediction of how these properties may vary in areas where data are lacking and therefore these may be of interest to acousticians. Analysis of reflection termination patterns in subbottom profile data are used to identify sediment deposited contemporaneously by a set of related depositional environments. A variation in the interval that separates reflections is usually related to a change in bed thickness. Closely spaced reflections are associated with environments of deposition where the mode of deposition changes frequently and those with widely spaced reflections are associated with environments where the mode of deposition rarely changes. Continuity of reflections is related to the lateral continuity of beds. Environments that have relatively short lateral continuity, such as terrestrial environments like river valleys that have been flooded, and many marginal marine environments are associated with reflections that have relatively short lateral continuity. These variations in separation and lateral continuity of beds and termination and orientation of beds that are all linked to variations in reflection character are produced by depositional processes that are associated with depositional systems and therefore distributed in a relatively predictable manner.

Increased extraction efficiency of acetonitrile/water mixtures for explosives determination in plant tissues

The standard extraction technique for analysis of explosives in dried soils for explosives analysis uses an 18 hour cooled sonication extraction in acetonitrile (ACN). In order to eliminate possible thermal degradation of explosive analytes during the drying step, water was allowed to act as a modifier for the acetonitrile extraction solvent in extraction of un-dried plant tissues resulted. The modified extraction solvent resulted in more efficient extraction of explosives analytes from these matrices compared to extractions in 100% ACN. In order to understand this increased extraction efficiency, extractions and analyses were performed on plant tissues that had been exposed to contaminated irrigation water with varied extraction solvents. Significant increases in extractability of explosives from plant tissues were noted with increasing water ratios. These observations were investigated using gravimetric, high performance liquid chromatographic, and environmental scanning electron microscopic analysis. The increased efficiency of water modified acetonitrile extraction solvents is explained by a secondary extraction effect.