Volume Of Ethyl Acetate Research Articles

Optimization of Insulin Yield from Extract of Stevia Leave (Rebaudiana Bertoni)

Stevia (Rebaudiana bertoni) leave, is an ancient perennial shrub mostly found in South America such as Paraguay and Brazil, it contains a low-calorie sweetener, which is about 300 times sweeter than sucrose. Insulin is a polypeptide hormone, which has an anabolic property, insulin has a vital role in regulation of carbohydrate metabolism, it also enhances the metabolism of fat and proteins and regulation of certain gene expression. Design expert software 10.0 was used to design the experimental data for the optimization of insulin yield in stevia (Rebaudiana bertoni) leave. Custom design with 3 factor and one response was applied, the independent variables were amount of stevia powder (g), volume of n-hexane (ml) and volume of ethyl acetate (ml) and the response is percentage of insulin yield (%). In this research work, insulin was successfully extracted from stevia (Rebaudiana bertoni) leave and the optimum yield was determined. The optimum extraction conditions for optimum yield of insulin were found to be: 5.668 g of stevia powder, 49.107 ml of n-hexane and 32.386 ml of ethyl acetate.

INFLUENCE OF MICROENCAPSULATION PARAMETERS ON THE SIZE AND MORPHOLOGY OF MICROCAPSULES BY ECO-FRIENDLY SOLVENT EVAPORATION METHOD ORIENTED TO MEDICAL TEXTILES

Application of microcapsules in medical textile has been studied and commercially developed widely in recent years. The aim of this work was to propose an eco-friendly microencapsulation by solvent evaporation method that can contribute to the manufacture of medical textile products using microcapsules. Quillaja saponin was used as bio-sourced surfactant and ethyl acetate was used as the less toxic, non-halogenated organic solvent. The influences of saponin concentration, stirring speed during emulsification step and the volume of ethyl acetate used to saturate the aqueous phase before emulsification on the microcapsule size and morphology were investigated. The results showed that eudragit microcapsules of ibuprofen with diameter in range from 17 to 34 µm, which were suitable for medical textile applications, were successfully elaborated. The saponin concentration varied from 0.025 to 0.1 wt%. The stirring speed was changed from 700 to 600 rpm. The volume of ethyl acetate used in saturation step was 0, 8 and 12 ml. In the scope of investigation, the saponin concentration and the volume of ethyl acetate used in saturation step did affect the microcapsule size and morphology while the stirring speed did not. The saturation step really helped to reduce the formation of irregular microparticles and to narrow the size distribution, but the microcapsules became more porous, weaker and were deformed significantly by drying in the fabric treatment process.

Natural deep eutectic solvent combined with ultrasonic enhancement: A green extraction strategy for solanesol in tobacco leaves

In this study, ultrasound-assisted natural deep eutectic solvent (NADES) extraction was shown to be a green and effective extraction strategy for solanesol in tobacco leaves. Several choline chloride-based (ChCl) NADESs were synthesized to evaluate the extraction efficiency, compared with traditional extraction methods, and the extracted solanesol was quantified using high performance liquid chromatography (HPLC). Influencing factors in the extraction process such as the molar ratio, water content, solid-liquid ratio, extraction temperature, extraction time, ultrasonic power, and ethyl acetate volume were optimized. The optimal conditions for extraction were the use of ChCl-Urea (1:2, 5 % water content (w:w)) as extractant at 40 °C with a solid-liquid ratio of 1:30, ultrasonication at 200 W for 80 min, followed by microextraction with 800 μL of ethyl acetate. Under these conditions, the extracted solanesol content was about 7.25 ± 0.06 mg·g −1 , which was 2.36, 1.87, and 1.87 times higher than that of methanol, ethanol, and ethyl acetate extracts, respectively. The characterization results of Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) could further elucidate the extraction mechanism. The method developed in this study can be effectively used to extract solanesol from waste tobacco leaves, which has potential applications in the food and pharmaceutical industries. • A NADES-based extraction method of solanesol was developed for the first time. • Extraction efficiencies of NADES were evaluated. • NADES was reused. • The extraction conditions was optimized.

Optimization of Vanillin Extraction from Biodegradation of Oil Palm Empty Fruit Bunches by Serpula lacrymans

Abstract This research aims to determine the combination of the ethyl acetate solvent volume and the extraction time that resulted in the optimum response of vanillin content and vanillin yield from the degradation of lignocellulose components from oil palm empty fruit bunches (OPEFB). First, OPEFB degraded using Serpula lacrymans to break down lignocellulosic components. The research design used a centralized composite design with two factors, the volume of ethyl acetate solvent (ml) and the extraction time (minutes). The responses of the experiment are vanillin content and vanillin yields. The optimization analysis results showed that the volume of ethyl acetate solvent and extraction time have a quadratic effect on the vanillin content and vanillin yields. The optimal solution was obtained by treatment with ethyl acetate volume 101.1 ml and extraction time 123.5 minutes. The optimal solution prediction results obtained vanillin content 0.014% and vanillin yield 7.302 μg/g with desirability of 92.8%. Validation based on the optimal solution’s prediction brought response vanillin content 0.013% and vanillin yield 6.950 μg/g. The vanillin content and yield validation results differed respectively by 4.081% and 4.826% lower when compared to predictions on the optimal solution. Keywords: ethyl acetate, vanillin content, vanillin yield

Quantification of Lupeol in Polyherbal Formulation by High-Performance Thin-Layer Chromatography Method Using Design of Experiments as a Tool to Assess Optimization of Method Development and Extraction Efficiency

A simple, specific, and quantitative high-performance thin-layer chromatographic (HPTLC) method has been developed for the quantitative determination of lupeol in 2 marketed formulations, namely, Manasamitra vatakam and Amree plus capsule. Chromatographic development was performed by using a pre-coated silica gel 60 F254 aluminum-backed plate, and the development was carried out using toluene—ethyl acetate (9.48:0.52, V/V) as the optimized mobile phase. The developed TLC plates were derivatized by using anisaldehyde—sulfuric acid reagent. The detection of lupeol was carried out at 600 nm. Box—Behnken design was applied for optimization of the chromatographic conditions, and combinations of factors, such as mobile phase composition (volume of ethyl acetate) (A), chamber saturation time (B), and migration distance (C) likely to affect RF, were identified from preliminary trials and further optimized using a response surface design. Among 3 factors, the significant factor found was the volume of ethyl acetate that resulted in higher change in the RF value and can be considered as a critical method parameter. Full factorial design was applied for optimization of extraction efficiency. The factors selected for the optimization process were volume of methanol (A) and duration of extraction (B) with percentage yield of extract as response. The linear ranges were found to be 500–3000 ng per band. The accuracy and precision measured were less than 2% relative standard deviation for lupeol. The sensitivity of the method in terms of the limit of detection (LOD) and the limit of quantification (LOQ) was measured. The proposed method was found to be accurate, precise, reproducible, robust, and specific and can be applicable for the determination of lupeol in the quality-control testing of extract and polyherbal formulations.

Morphology control of perovskite in green antisolvent system for MAPbI3-based solar cells with over 20% efficiency

Solvent engineering has been considered a reliable process for the fabrication of pinhole-free and highly crystalline perovskite thin films. Recently, green solvents have received immense attention, as the toxic antisolvents used in the conventional fabrication process cause environmental and health hazards. In this regard, ethyl acetate (EA) is a promising environmentally friendly antisolvent. Here, we present the fabrication of perovskites with controlled morphologies by changing the composition of the perovskite and the volume of EA in ambient humidity. The incorporation of [HC(NH2)2]PbIBr2 into a CH3NH3PbI3 matrix results in a grain size up to ~1.5 μm. This induces a considerable reduction of trap density, leading to the suppression of charge recombination and, consequently, improvement in the photoluminescence characteristics. The resulting power conversion efficiencies (PCEs) of the optimized devices are 20.93% and 19.51% for active areas of 0.12 cm2 and 0.7 cm2, respectively. The reduced diffusion of moisture along grain boundaries improves device stability. Further, by virtue of the excellent humidity resistance of EA, the film morphologies obtained at high relative humidity (50%) are similar to those obtained under dry conditions, exhibiting an impressive PCE of 20.11%. We believe that our optimized fabrication process using EA can be extended to other green antisolvent systems.

Factorial design for development of a high-performance thin-layer chromatography method for the simultaneous estimation of abacavir sulfate, lamivudine hydrochloride, and dolutegravir sodium

A high-performance thin-layer chromatography (HPTLC) method has been developed for the simultaneous estimation of abacavir sulfate (ABC), lamivudine hydrochloride (LAM), and dolutegravir sodium (DTG) in an in-house physical mixture and it was validated as per the International Conference on Harmonization (ICH) guidelines. A 23 full factorial design was utilized to aid in method development and optimization. Effective chromatographic separation was achieved using pre-coated silica gel aluminum HPTLC plate 60 F254 as the stationary phase and ethyl acetate—ethanol—acetone—ammonia (4.478:0.740:0.50:0.15, v/v) as the mobile phase. The optimized chamber saturation time was kept at 30 min. Densitometric scanning was performed in the absorbance—reflectance mode at a detection wavelength of 267 nm. Quality by design approach was applied to evaluate the effect of all three factors, i.e., volume of ethyl acetate, volume of ethanol, and volume of acetone, on the chromatographic response retardation factor (RF) of each drug. The RF values of ABC, LAM, and DTG were found to be 0.65, 0.34, and 0.26, respectively. The calibration curves were found to be linear by taking independently weighed standard solutions with concentrations of 4.8, 7.2, 9.6, 12.0, and 14.4 μg per band for ABC, 2.4, 3.6, 4.8, 6.0, and 7.2 μg per band for LAM, and 0.4, 0.6, 0.8, 1.0, and 1.2 μg per band for DTG. The limit of detection and limit of quantification values were found to be 0.9972 μg per band and 3.0218 μg per band for ABC, 0.2544 μg per band and 0.7711 μg per band for LAM, and 0.1004 μg per band and 0.3043 μg per band for DTG, respectively. The % recoveries of the drugs by the developed method were found in the range of 98.0955–100.9813% for ABC, 98.2616–99.9900% for LAM, and 98.4666–101.3000% for DTG, respectively. The proposed method was found to be novel, simple, accurate, reproducible, and robust. The developed HPTLC method was successfully applied for the quantitative determination of ABC, LAM, and DTG in an in-house physical mixture.

Simultaneous determination of organochlorine and pyrethriod pesticide residues in the Chinese patent medicines by gas chromatography-tandem mass spectrometry

ABSTRACTA simple, sensitive, reliable method was developed for the simultaneous determination of organochlorine and pyrethriod pesticide residues in Chinese patent medicines Six ingredient rehmannia pills and Xiaoyao pills. These pesticides were extracted by ethyl acetate. The extraction time and volume of ethyl acetate were optimized. Cleanup of extracts was performed with dispersive-solid phase extraction using graphitized carbon black as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography–tandem mass spectrometry in multiple reaction monitoring mode (GC-MS/MS, MRM). The linearity of the calibration curves is good in matrix-matched standard and yields the coefficients of determination (R2) ≥0.99 for all of the target analytes. Under optimized conditions, the average recoveries (five replicates) for most pesticides range from 75.5% to 114.6%, and RSDs are less than 10.0%. The LODs of 18 pesticides in Six ingredient rehmannia pill and Xiaoyao pills are in the range of 0.01–8.82 μg kg−1. The developed method meets the requirements of pesticide residue analysis and could be effectively used for routine analysis of the organochlorine and pyrethriod pesticide residues in Six ingredient rehmannia pills and Xiaoyao pills.

Determination of Phthalate Esters in Plastic Track Surface Layer Material by Gas Chromatography

A method was proposed to simultaneously and rapidly determine the content of five kinds of phthalate esters (DMP, DBP, BBP, DnHP, DOP) in plastic track surface layer material by gas chromatography (GC) with the external standard,and the method was first proposed. The sample pretreatment method was microwave-assisted extracted using ethyl acetate as the solvent. Discussed the effects of extraction conditions on the extraction efficiency, microwave extraction time was 30 minutes, microwave extraction temperature was 100°C,the volume of ethyl acetate was 15mL. The results showed that there was a good linear relationship in range of 0.040 to 50 mg/L(R2 was 0.9987-0.9994). The average recoveries of standard addition for five kinds of phthalate esters were between 83.83% and 101.02%, and the relative standard derivations (RSDs (n=6)) ranged from 0.95% to 4.73%. The three times of signal to noise ratio (3 S/N) was used to calculate the detection limit of the method , and the detection limit was 2.5-3.0 mg/kg. The ten times of signal to noise ratio (10 S/N) was used to calculate the quantitation limit of the method, and the limit of quantitation was 8.5-10 mg/kg. This method is simple, effective and suitable for the determination of phthalate esters in plastic track surface layer material.

Use of Ca-alginate immobilized Pseudomonas aeruginosa for repeated batch and continuous degradation of Endosulfan.

The current investigation is taken up with the aim of studying repeated batch and continuous degradation of Endosulfan, using Ca-alginate immobilized cells of Pseudomonas aeruginosa isolated from an agricultural soil. The work involves the study of genes and enzymes involved in the degradation of the pesticide and was carried out with an objective of reducing the toxicity of Endosulfan by degrading it to less toxic metabolites. The long-term stability of Endosulfan degradation was studied during its repeated batch degradation, carried out over a period of 35 days. Immobilized cells of Ps. aeruginosa were able to show 60 % degradation of Endosulfan at the end of the 35th cycle with a cell leakage of 642 × 104 Cfu/mL. During continuous treatment, with 2 % concentration of Endosulfan, 100 % degradation was recorded up to 100 mL/h flow rate and with 10 % concentration of the Endosulfan, and 100 and 85 % degradation was recorded at 20 mL/h flow rate and 100 mL/h flow rate, respectively. After degradation of Endosulfan, products were extracted from a large amount of spent medium using two volumes of ethyl acetate and subjected to the LC–MS analysis. Endosulfan lactone and Endosulfan ether were the products of degradation detected by the LCMS analysis. Plasmid curing experiments indicated that genes responsible for the degradation of Endosulfan are present on the chromosome and not on the plasmid, as growth of Ps. aeruginosa was observed on modified non-sulfur medium with Endosulfan after the plasmid was cured with ethidium bromide. The results of PCR indicated that there is no amplified product of ~1350 bp expected for esd gene, in Ps. aeruginosa, although there were some non-specific bands. Enzymatic degradation studies indicated that the enzymes involved in the degradation of Endosulfan are intracellular. With this investigation, it was indicated that immobilized cells of Ps. aeruginosa have the potential to be used in the bioremediation of water contaminated with Endosulfan.

Antimicrobial Activity of Potato Rhizospheric Pseudomonas chlororaphis subsp. aureofaciens from Sétif Algeria

Aims: This study was assessed to demonstrate the antimicrobial activity in vitro of an identified fluorescent Pseudomonas strain characterized for its capacity to produce phenazine compounds. Methodology: First Pseudomonas chlororaphis subsp aureofaciens was inoculated on Nutrient Broth supplemented with Yeast Extract (NBY) and with glucose at a final concentration of 2%, after incubation the filtered culture was acidified with HCl to pH 2. The solution was extracted twice with the same volume of ethyl-acetate. The organic supernatants were combined, dried over anhydrous Na2SO4, and evaporated to dryness. The crude extract was resuspended in methanol and tested for antimicrobial activity. Antimicrobial activity was determined (i) by disc diffusion technique for bacteria and (ii) using serial dilution technique in soft PDA for fungi. Secondly the antifungal activity of the bacterial strain was tested against several phytopathogenic fungi in dual culture. Results: The studied strain has an important activity against the phytopathogenic bacteria and fungi tested. Among the tested fungi Fusarium oxysporum f. sp. albedinis is the most sensitive to the actions of this Pseudomonas, where the inhibition rate reached 77.78%. The less sensitive one was Pythium ultimum with a rate of 55.56%. While for pathogenic bacteria only Salmonella enteridis was sensitive to the tested strain. Conclusion: Pseudomonas chlororaphis subsp aureofaciens showed appreciable antagonistic activity, in vitro, against special forms of Fusarium oxysporum and the tested phytopathogenic bacteria.

Determination of Tetracyclines in Water by Ethyl Acetate–Ionic Liquid Dispersive Liquid–Liquid Microextraction and High-Performance Liquid Chromatography

An ethyl acetate-assisted ionic liquid dispersive liquid–liquid microextraction method was developed for the determination of tetracyclines in water samples with high-performance liquid chromatography using a variable wavelength detector. A mixture of ethyl acetate and 1-butyl-3-methylimidazolium hexafluorophosphate was used to isolate lanthanum(III) chelates of tetracyclines. The addition of ethyl acetate significantly enhanced the extraction efficiencies. Experimental parameters affecting the efficiency such as the identity and volume of ionic liquid, the volume of ethyl acetate, chelating time, centrifuge time, pH, and ionic strength were evaluated. Under the optimum conditions, the calibration curves were linear and the correlation coefficients (r 2 ) ranged from 0.9985 to 0.9992 over concentration levels of 0.01–0.50 µg mL−1. The limits of detection (signal-to-noise ratio = 3) of the method ranged from 0.97 to 1.14 ng mL−1, whereas inter- and intra-day relative standard deviations (n = 5) were between 2.4–4.3% and 3.6–6.8%, respectively. This method was used to analyze water samples and recoveries from 62.6% to 109.6% were obtained.

Studies on statistical optimization of sulforaphane production from broccoli seed

Background: Natural sulforaphane (SF) has been of increasing interest for nutraceutical and pharmaceutical industries due to its anti-cancer effect. The main objective of the present work was to optimize the production of SF from broccoli seed using response surface methodology. Results: Three major factors (hydrolysis time, water volume and ethyl acetate volume) were screened out through Plackett-Burman (PB) factorial design. The methods of steepest ascent combined with central composite design (CCD) were employed for optimization of the SF production process. The optimal extraction conditions for SF production were a hydrolysis time of 13 min, a hydrolysis volume/weight ratio of 2.9:1 (v/g) and an extraction volume/weight ratio of 17.5:1 (v/g). The maximum SF yield was 14.8 ± 0.1 mg/g, a value that was in perfect agreement with the actual experimental value (14.8 mg/g). Conclusions: These results suggested that PB design combined with CCD were proved effective in screening and optimization of the parameters of SF production.

Novel Binary Solvents-Dispersive Liquid—Liquid Microextraction (BS-DLLME) Method for Determination of Patulin in Apple Juice Using High-Performance Liquid Chromatography

A simple and rapid binary solvents-based dispersive liquid–liquid microextraction (BS-DLLME) method has been developed for determination of patulin (PAT) in apple juice followed by high-performance liquid chromatography. This method involves the use of an appropriate mixture of miscible binary extraction solvents and disperser solvent to form fine droplets of extractant in a sample solution. Parameters affecting extraction efficiency such as the type and volume of high-density extraction solvent, the volume of ethyl acetate, the kind and volume of disperser solvent, and salt addition were investigated and optimized. The detection and quantification limits were 2.0 and 10.0 μg L−1, respectively. The relative standard deviation for five measurements of 25 μg L−1 of PAT was 3.8 %. The relative recoveries of PAT from apple juice samples at spiking levels of 25, 50, and 75 ng mL−1 were in the range of 91.3–95.2 %.

Studies on the culturable marine actinomycetes isolated from the Nahoon beach in the Eastern Cape Province of South Africa

A total of 84 culturable marine actinomycetes belonging to 15 generic morphotypes were isolated from water and rock scrapings from the Nahoon beach, a coastal shore of Indian Ocean in the Eastern Cape Province of South Africa. The colonies showed diverse morphological characteristics and their occurrence and distribution varied with sample type. The rock scrappings yielded more actinomycetes morphotypes than the water samples. Streptomyces was most prevalent in both samples.Actinoplane, Actinosynnema, Norcadia, Norcardiopsis, Streptosporagium and Intrasporagium were present in rock scrapings but absent in water samples. Kibdellosporium was present in water sample and absent in rock scrapings. The Streptomyces isolates were selected and preliminarily screened for antimicrobial activity. The bioactive compounds of 10 most potent Streptomyces isolate was extracted twice with equal volume of ethyl acetate (1:1 v/v). The ethyl acetate extracts of the putative Streptomyces isolates showed activities against at least 6 and up to 26 of the 32 test bacteria screened. Inhibition zones were found to range between 9 and 32 mm diameters at a concentration of 10 mg/ml. The partial characterization of the crude extracts by IR spectra analysis revealed the possible presence of terpenoid, long chain fatty acids and secondary amine derivatives compounds in the extracts. We conclude that the Nahoon beach promises to be a veritable resource for diverse marine actinomycetes of potentials for bioactive compounds production and novel drug discovery. Key words: Morphotypes, occurrence, rock scrapings, IR spectral, bioactive compound.

Functional Redundancy of Steroid C26-monooxygenase Activity in Mycobacterium tuberculosis Revealed by Biochemical and Genetic Analyses

One challenge to the development of new antitubercular drugs is the existence of multiple virulent strains that differ genetically. We and others have recently demonstrated that CYP125A1 is a steroid C(26)-monooxygenase that plays a key role in cholesterol catabolism in Mycobacterium tuberculosis CDC1551 but, unexpectedly, not in the M. tuberculosis H37Rv strain. This discrepancy suggests that the H37Rv strain possesses compensatory activities. Here, we examined the roles in cholesterol metabolism of two other cytochrome P450 enzymes, CYP124A1 and CYP142A1. In vitro analysis, including comparisons of the binding affinities and catalytic efficiencies, demonstrated that CYP142A1, but not CYP124A1, can support the growth of H37Rv cells on cholesterol in the absence of cyp125A1. All three enzymes can oxidize the sterol side chain to the carboxylic acid state by sequential oxidation to the alcohol, aldehyde, and acid. Interestingly, CYP125A1 generates oxidized sterols of the (25S)-26-hydroxy configuration, whereas the opposite 25R stereochemistry is obtained with CYP124A1 and CYP142A1. Western blot analysis indicated that CYP124A1 was not detectably expressed in either the H37Rv or CDC1551 strains, whereas CYP142A1 was found in H37Rv but not CDC1551. Genetic complementation of CDC1551 Δcyp125A1 cells with the cyp124A1 or cyp142A1 genes revealed that the latter can fully rescue the growth defect on cholesterol, whereas cells overexpressing CYP124A1 grow poorly and accumulate cholest-4-en-3-one. Our data clearly establish a functional redundancy in the essential C(26)-monooxygenase activity of M. tuberculosis and validate CYP125A1 and CYP142A1 as possible drug targets.

Computer-assisted optimization of liquid-liquid extraction for HPLC analysis of domperidone and pantoprazole in human plasma

Summary This paper deals with optimization of a liquid-liquid extraction procedure for simultaneous HPLC analysis of domperidone and pantoprazole in human plasma. Central composite design and Derringer's desirability function were used to optimize the concentration of KOH and the volume of ethyl acetate as the main factors affecting the liquid-liquid extraction procedure. After extraction, the analytes were separated quantitatively on a C18 column with 10 mM pH 7.0 phosphate buffer-methanol-acetonitrile 48.46:20:31.54 (υ/υ) as mobile phase at a flow rate of 1.20 mL min−1 and with UV detection at 285 nm. It was concluded that extraction recovery of both the analytes was affected by KOH concentration and that recovery of pantoprazole was affected by ethyl acetate (extraction solvent) volume. Extraction recovery under optimum extraction conditions was 93.52% for domperidone and 92.72% for pantoprazole. The optimized extraction method was validated. Linearity was established for six levels in the ranges 10–1000 ng mL−1 for pantoprazole and 15–1000 ng mL−1 for domperidone. The lower limit of quantitation (LLOQ) and detection (LOD) were estimated as 9.84 and 5.91 ng mL−1, respectively, for pantoprazole and 14.56 and 8.79 ng mL−1 for domperidone. The optimized method was linear, specific, accurate, and precise; the high recovery (>92%) and low relative standard deviation (<2.5%) enable reliable quantification of these analytes in spiked human plasma.

In Vitro Synthesis of Oleoylglycine by Cytochrome c Points to a Novel Pathway for the Production of Lipid Signaling Molecules

Long chain fatty acyl glycines represent a new class of signaling molecules whose biosynthetic pathway is unknown. Here we report that cytochrome c catalyzes the formation of oleoylglycine from oleoyl-CoA and glycine, in the presence of hydrogen peroxide. The identity of oleoylglycine product was confirmed by isotope labeling and fragmentation mass spectrometry. Synthesis of oleoylglycine by cytochrome c was dependent upon substrate concentration and time. Other heme-containing proteins, myoglobin and hemoglobin, did not catalyze oleoylglycine synthesis. The functional properties of the reaction closely resemble those observed for the ability of cytochrome c to mediate the synthesis of oleamide from oleoyl-CoA and ammonia, in the presence of hydrogen peroxide (Driscoll, W. J., Chaturvedi., S., and Mueller, G. P. (2007) J. Biol. Chem. 282). The ability of cytochrome c to catalyze the formation of oleoylglycine experimentally indicates the potential importance of cytochrome c as a novel mechanism for the generation of long chain fatty acyl glycine messengers in vivo.

Rapid method for the determination of polycyclic aromatic hydrocarbons in agricultural soils by sonication-assisted extraction in small columns

A rapid method has been developed for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in soil based on their sonication-assisted extraction in small columns (SAESC) with a low volume of ethyl acetate and subsequent quantitation and identification by GC with electron impact mass spectrometric detection in the SIM mode (GC-MS-SIM). Spiked blank soil extracts were used as standards to counteract the matrix effect observed in the chromatographic determination. PAHs were confirmed at trace level by their retention times, their qualifier and target ions, and their qualifier/target abundance ratios. Recovery studies were performed at 0.5, 1.0, 5.0, and 10 microg/kg fortification levels for each PAH, and the recoveries obtained ranged from 91.2 to 99.8% with RSDs between 0.4 and 9.3%. The detection limits of the method ranged from 0.03 to 0.3 microg/kg for the different PAHs studied. The developed method is linear over the range assayed, 1-100 microg/L with determination coefficients higher than 0.996. PAH levels were determined using this method in soil samples taken from different agricultural areas of Spain. In general, PAH concentrations were low and the most frequently occurring PAHs were naphthalene, pyrene, phenanthrene, and fluoranthene.

Monolithic silica capillary column extraction of methamphetamine and amphetamine in urine coupled with thin-layer chromatographic detection

A monolithic silica capillary column was first developed in Japan in 2001 as a new tool for better liquid chromatographic separation. The column is made of C18-bonded monolithic silica packed into a capillary glass tube (0.20 mm i.d.). In this study, we used this column for solid-phase extraction of methamphetamine (MA) and amphetamine (AP) in urine. Chromatographic separation was achieved by thin-layer chromatography (TLC) with double-spray detection of each spot. For extraction of amphetamines in urine, samples were mixed with phosphate buffer (pH 3.0, containing 20mM sodium octanesulfate), and the analytes were adsorbed to the column by passing the mixture through it. They were then eluted with a 10-μl volume of ethyl acetate and directly spotted onto a TLC plate. After development, the detection of MA was performed with Simon’s reagent. The plate was air-dried, and then over-sprayed with fluorescamine reagent for detection of AP. A fluorescent spot of AP was observed at 365 nm using an ultraviolet viewing system. The detection limits of MA and AP in urine were about 1.0 and 2.0μg/ml, respectively. To confirm the usefulness of this method, the eluent from the column was also analyzed by gas chromatography-mass spectrometry (GC-MS) after derivatization with heptafluorobutyric anhydride. In analysis of 30 actual urine samples, the results obtained by the monolith-TLC system were generally well in accordance with those obtained by GC-MS.