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ABSTRACT: In this study the modern microextraction by packed sorbent (MEPS) method followed by HPLC-UV analysis was optimised and evaluated for determination of l-ascorbic acid (AA) content in beverages. In this case 300μL of sample was passed through silica BIN (barrel insert and needle assembly) and entrapped AA was eluted by 60μL of methanol-water (10%, v/v) solution. Recovery of the proposed method for three concentration levels ranged between 97.46% and 106.88% with relative standard deviation 8.7% (low conc.), 2.49% (medium conc.) and 1.98% (high). Obtained results of AA contents in real samples were in the ranges 56.5-195.4μg/mL and 130.4-1090.0μg/mL for ice-tea and fruit juice samples, respectively. Proposed method was compared with iodometric titration and DPPH methods, but microextraction method was found to be more selective for AA determination in tested samples.
Food Chemistry 12/2012; 135(3):1613-8. · 3.65 Impact Factor
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ABSTRACT: A method employing the direct immersion solid-phase microextraction followed by GC-MS analysis is presented for the determination of essential oils components in herbal tea infusions, i.e. their direct content in the liquid phase. The extraction performances were compared using five different microextraction fibres. Significant parameters affecting sorption process such as sample amount, sorption and desorption time and temperature, stirring speed, pH adjustment and effect of ionic strength were optimised and discussed. By optimising the key parameters, a detection limits (LOD = S/N × 3) for ten target marker compounds were obtained in the range from 5.3 to 48.2 ng/mL with recoveries ranged between 93.03 and 100.50%. Intra-day and inter-day repeatability at three concentration levels were found to be 1.1-15.3 and 7.2-15.5% RSD, respectively. Finally, the optimised procedure enabling a rapid and simple analysis of essential oils was applied for the direct determination of these compounds in ten herbal tea infusions.
Journal of Separation Science 11/2012; · 2.73 Impact Factor
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ABSTRACT: A method for focused ultrasonic extraction of nitroglycerin, triphenyl amine and acetyl tributyl citrate presented in double-base propellant samples following by the gas chromatography/mass spectrometry analysis was developed. A face-centered central composite design of the experiments and response surface modeling was used for optimization of the time, amplitude and sample amount. The dichloromethane was used as the extractant solvent. The optimal extraction conditions with respect to the maximum yield of the lowest abundant compound triphenyl amine were found at the 20min extraction time, 35% amplitude of ultrasonic waves and 2.5g of the propellant sample. The results obtained under optimal conditions were compared with the results achieved with validated Soxhlet extraction method, which is typically used for isolation and pre-concentration of compounds from the samples of explosives. The extraction yields for acetyl tributyl citrate using both extraction methods were comparable; however, the yield of ultrasonic extraction of nitroglycerin and triphenyl amine was lower than using Soxhlet extraction. The possible sources of different extraction yields are estimated and discussed.
Talanta 09/2012; 99:316-22. · 3.79 Impact Factor
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ABSTRACT: The analytical method based on the high-performance liquid chromatography coupled with UV detection (HPLC/UV) for determination
of selected antioxidants (i.e., esculetin, scopoletin, 7-hydroxycoumarine, rutin, xanthotoxin, 5-methoxypsoralen and quercetin) in plant material was developed.
Pressurised fluid extraction (PFE) and ultrasonic extraction (USE) methods for the isolation of these compounds from ten real
plant samples were used. Both extraction methods were optimised and compared to each other. For the proposed HPLC/UV method
the LOQ values (limit of quantification) in the range from 22.7 (xanthotoxin) to 97.2 ng mL−1 (rutin) were obtained. For all extracts the antioxidant capacity based on the reduction of free 2,2-diphenyl-1-picrylhydrazyl
radical (DPPH) was also determined. Results ranged from 82.04 to 94.43% of DPPH radical inhibition for PFE method and from
76.01 to 89.94% in the case of USE method.
KeywordsPressurised Fluid Extraction-Ultrasonic Extraction-Antioxidants-Antioxidant Capacity-High-Performance Liquid Chromatography
Central European Journal of Chemistry 04/2012; 8(1):87-95. · 1.07 Impact Factor
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ABSTRACT: The analytical microextraction methods of gas chromatography coupled with flame ionisation detector (GC-FID) for determination
of selected essential oils in herbs were proposed. Two microextraction methods for the isolation of essential oils from plants
such as Lavandula spica L., Melissa officinalis L., Mentha piperita L. and Salvia officinalis L. were used. The methods of solid-phase and single-drop microextractions, were optimised and compared. The obtained LOD
values for all studied essential oils were found to be within 2.5–20.5 μg for SDME and 57.0–139.8 μg for SPME method per 100
g of dried sample leaves. The appropriate LOQ values were then 8.4–68.4 μg for SDME and 189.8–466.1 μg for SPME of target
analytes per 100 g of dried sample leaves.
Central European Journal of Chemistry 04/2012; 7(3):303-311. · 1.07 Impact Factor
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ABSTRACT: The analytical method based on the HPLC coupled with UV detection (HPLC-UV) for the determination of selected antioxidants (i.e. esculetin, scopoletin, 7-hydroxycoumarine, rutin, xanthotoxin, 5-methoxypsoralen and quercetin) in plant material was developed. Two ultrasonic extraction methods for the isolation of these compounds from the plants such as Mentha longifolia L., Mentha spicata L., Ruta graveolens L., Achyllea millefolium L., Plantago lanceolata L. and Coriandrum sativum L. were used. Both of these methods, i.e. ultrasonic probe and ultrasonic bath, were optimised and compared to each other. For the proposed HPLC-UV method LOQ values in the range from 22.7 (xanthotoxin) up to 97.2 ng/mL (rutin) were obtained. For all extracts the antioxidant capacity based on the reduction of free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was also determined. Obtained results ranged from 10.11 up to 73.50% of DPPH radical inhibition.
Journal of Separation Science 01/2009; 32(2):288-94. · 2.73 Impact Factor
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ABSTRACT: Supercritical fluid extraction (SFE) with CO(2), a clean and rapid alternative to conventional Soxhlet extraction, was investigated for the extraction of nitro compounds from soil samples. Quantitative extraction by SFE was accomplished at a pressure of 25 MPa and an extraction temperature of 60 degrees C, for 30 min in dynamic mode and using acetonitrile as modifier, and the results were comparable with those obtained by acetonitrile Soxhlet extraction (3 h) for all soil samples. Extracts from these two procedures were analyzed by gas chromatography coupled with mass spectrometry. Quantitative reproducibility for SFE extracts was acceptable (RSD 2-10%), and the quantity of solvent was reduced from 160 mL for Soxhlet extraction to 5 mL in the case of SFE.
Journal of Separation Science 06/2008; 31(8):1408-14. · 2.73 Impact Factor
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ABSTRACT: A method employing the headspace single-drop microextraction (HS-SDME) is presented for the determination of essential oils in dried herbal leaves. By optimising the key experimental parameters, a linear response for the individual target compounds was obtained in the concentration range from LOQ to 4 mg/mL (r(2) = 0.9912-0.9998), with LODs from 3.3 up to 20.5 microg per 100 g of dried leaves, and the repeatability within the RSD of 2.1-8.9%. The HS-SDME-based procedure, enabling a rapid and simple analysis of essential oils in herbs, was applied to selected real samples (nine essential oils in four different samples) in combination with GC-FID identification and quantification of the target volatiles.
Journal of Separation Science 03/2008; 31(2):356-63. · 2.73 Impact Factor
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ABSTRACT: The effects of various parameters, i.e. extraction pressure, temperature, time, and modifier on the efficiency of extraction
were investigated using an analytical-scale supercritical fluid extraction system. An optimal set of conditions for the extraction
and determination by gas chromatography-mass spectrometry of trimethylsilyl derivatives of 4-androstene-3,17-dione, 1,4-androstadiene-3,17-dione,
nandrolone, and testosterone in nutritional supplements was developed. The optimum amount of creatine supplement was 1 g,
while the optimum pressure and temperature were determined to be 35 MPa and 80 °C, respectively. The optimum dynamic extraction
time was 45 min. The limit of detection (LOD) of the investigated compounds ranged from 5 to 25 ng · g−1 of supplement, while recoveries ranged from 76.1 to 86.6%.
Microchimica Acta 12/2007; 160(1):113-118. · 3.03 Impact Factor
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ABSTRACT: In the present paper, the following extraction techniques have been used for extracting isoflavonoids from the species Matricaria recutita, Rosmarinus officinalis, Foeniculum vulgare, and Agrimonia eupatoria L.: supercritical fluid extraction (SFE), pressurized fluid extraction, matrix solid phase dispersion, ultrasonic extraction in an ultrasonic bath (USE) and by means of an ultrasonic homogeniser (HOM), extraction by means of Soxhlet apparatus (SOX), and solid phase extraction. Experimental optimization of all techniques has been carried out using a soybean flour. Subsequent analyses of the extracts were carried out by liquid chromatography with UV detection. The maximum yields of daidzein and genistein were obtained by extraction with the SOX, USE, and HOM techniques. The maximum yields of apigenin and biochanin A from herb samples were obtained by SFE.
Journal of Separation Science 02/2007; 30(1):122-7. · 2.73 Impact Factor
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ABSTRACT: In the present paper, the following extraction techniques have been used for extracting isoflavonoids from the species Matricaria recutita, Rosmarinus officinalis, Foeniculum vulgare, and Agrimonia eupatoria L.: supercritical fluid extraction (SFE), pressurized fluid extraction, matrix solid phase dispersion, ultrasonic extraction in an ultrasonic bath (USE) and by means of an ultrasonic homogeniser (HOM), extraction by means of Soxhlet apparatus (SOX), and solid phase extraction. Experimental optimization of all techniques has been carried out using a soybean flour. Subsequent analyses of the extracts were carried out by liquid chromatography with UV detection. The maximum yields of daidzein and genistein were obtained by extraction with the SOX, USE, and HOM techniques. The maximum yields of apigenin and biochanin A from herb samples were obtained by SFE.
Journal of Separation Science 12/2006; 30(1):122 - 127. · 2.73 Impact Factor
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ABSTRACT: This paper deals with the application of supercritical extraction to isolation of additives from samples of smokeless powders, as an to classical fluid extractions (using Soxhlet apparatus or ultrasonication). The reasons for introduction of new extraction techniques are the decrease in volume of the solvents used for extraction and shortening the time of extraction, which usually takes several hours or even days. In the supercritical fluid extraction it is necessary to optimize the basic extraction parameters (temperature, pressure, modifier, treatment of the sample by means of grinding and the lenght of static step).
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ABSTRACT: The article is focused on the pressurised fluid extraction - PFE technique using of a one PSE device and its application to isolation of various organic compounds from solid samples. In this paper optimisation procedure for individual analytes is described and discussed. Applicability of PFE is tested on isolation procedures of phthalates, PAHs and TPHs from environmental materials (soils, river sediments), and the additives in smokeless gunpowders.
