• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.120-143
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• 2018

The analytical methods and their ambient levels of organic nitrogenous compounds such as nitrosamines, nitramines (nitroamines), imines, amides and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) in the atmosphere are summarized and discussed. Sampling for the analysis of organic nitrogenous compounds was mostly conducted using high volume air sampler. The direct liquid extraction (DLE) using sonification and the pressurized liquid extraction (PLE) using the accelerated solvent extraction (ASE) have been frequently employed for the extraction of organic nitrogenous compounds in the atmospheric samples. After extraction, clean-up via filtration and the solid phase extraction (SPE) and concentrations using nitrogen and rotary evaporator have been generally conducted but in some studies the clean-up and concentration steps have been omitted to prevent the loss of analyte and improve the recovery rate of the analytical procedure. Instrumental analysis was mainly carried out using gas chromatography (GC) or the high performance liquid chromatography (HPLC) coupled with the single quadrupole mass spectrometer or tandem mass spectrometer in the electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) mode and analysis sensitivity of nitrosamines and nitramines were higher in NCI mode. Desirable sampling and analysis methods for analyzing particulate organic nitrogenous compounds are suggested.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.2
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• pp.248-253
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• 2006

For the determination of vitamin I using high performance liquid chromatography (HPLC), the most critical and time consuming step is the Quantitative extraction of all vitamin E homologs from sample matrix. Three different extraction methods were compared to determine vitamin E in grains. Saponification used alkaline hydrolysis followed by solvent extraction. Direct solvent extraction included dispersing the samples in hot water, addition of isopropanol and $MgSO_4$, and extraction of the analytes with extracting solvent with Polytron homogenization. Using Soxhlet extraction, the samples were extracted in a Soxhlet apparatus with hexane containing butylated hydroxytoluene (BHT). Vitamin E content in 14 grains were analyzed and compared by three different extraction methods. Generally, the highest values were observed from direct solvent extraction and Soxhlet extraction followed by saponification. a-Tocopherol equivalent (a-TE) levels in grains ranged from 0.32 a-TE/100 g in prosomillet to 5.12 a-TE/100 g in black rice.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.171-178
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• 2013

BACKGROUND: Consensus of heavy metal phytoavailability in soils needs to be introduced for soil management protocols in relation to safer food production in the contaminated agricultural soils. For this, setting up the method for evaluation of metal phytoavailability in soil is an essential prerequisite. METHODS AND RESULTS: The current study was carried to select a proper single extraction method for determination of phytoavailable metal concentration in soil. Two extraction methods were examined including 1 M $NH_4NO_3$ extraction and 0.01 M $Ca(NO_3)_2$ extraction methods using 142 soil samples collected from the agricultural soils nearby abandoned mining area in Korea. Corelation analysis was conducted between phytoavailable metal concentrations and soil properties potentially influencing on the metal phytoavailability. Both methods showed similar significance (p<0.001) in correlation with soil properties such as soil pH. However, higher correlation coefficients between phytoavailable metal concentrations and soil properties were observed when used $Ca(NO_3)_2$ extraction rather than using $NH_4NO_3$ extraction. CONCLUSION(S): It appeared that 0.01 M $Ca(NO_3)_2$ extraction was better option for determination of phytoavailable metals in soils and further study to test the efficiency of this method is required in combination with plant uptake.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.111-116
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• 2016

To determine the optimum condition for the extraction of active components, noni adventitious roots were extracted under various conditions employing various solvents including methanolic water at different ratio (20, 40, 60, 80, and 100% water), extraction times and extraction methods. Anthraquinones, phenolic compounds, and flavonoids extraction using different solvents showed that 1 h of ultrasonic extraction was effective in 60-80% methanol, and 2 h of reflux extraction was effective in 80% methanol. To compare the extraction efficiency of active components according to different extraction methods and extraction times for noni adventitious roots, the active components were extracted by ultrasonic extraction, shaking extraction, reflux extraction, homogenizer extraction, high-pressure extraction, and soaking extraction. The highest phenolic contents were found in the extracted from ultrasonic extraction and anthraquinones and flavonoids contents were highest in the reflux extraction.

• The Korean Journal of Food And Nutrition
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• v.17 no.4
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• pp.412-419
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• 2004

In odor to select optimum extraction methods of volatile compounds in beef extract powder(BEP) as basic data for the development of a new detection method of irradiated BEP, four extraction methods, such as solid phase microextraction with polar fiber(S-PD) and non-polar fiber(S-CD), purge and trap(P&T) and liquid liquid continuous extraction(LLCE) methods, were tested with gas chromatography/mass spectrometry method. A total of 106 volatile compounds including 22 hydrocarbons, 7 aldehydes, 6 ketones, 13 alcohols, 6 sulfur-containing compounds, 19 nitrogen-containing compounds, 6 aromatic compounds, 17 terpenes, 8 furans and 2 miscellaneous compounds were detected in BEP by four detection methods. The most compounds(62 compounds) were detected by S-PD method, followed by P&T(43), LLCE(38) and S-CD method(30). Among these methods, S-PD and P&T methods showed a complementary interrelationship to detect volatile compounds as S-PD method showed high detectabiltiy to all compound groups except hydrocarbons and ketones, which had high volatility and low molecular weight(less than RI 1200), but P&T method showed the contrary pattern to that of S-PD method. Moreover, the most of volatile compounds detected by S-CD and LLCE methods were also detectable by S-PD or/and P&T methods. Therefore, the simultaneous application of S-PD and P&T methods were selected as the optimum volatile extraction methods of BEP.

• Korean journal of food and cookery science
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• v.23 no.1 s.97
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• pp.150-155
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• 2007

This work was conducted to obtain a rapid, accurate, and precise procedure for free amino acids analysis in Doenjang with HPLC-OPA (high performance liquid chromatography using-phthalaldehyde) and AAA (automatic amino acid analyzer) methods. Different sample extraction procedures among water, 0.1 M perchloric acid, and 0.1% meta-phosphoric acid were also compared. The optimal extraction solvent was 0.1% meta-phosphoric acid for both the HPLC-OPA and AAA methods. Good recoveries for glycine and methionine were observed using the 0.1% meta-phosphoric acid extraction with HPLC-OPA method. Method precisions (% relative standard deviation) for the free amino acids ranged for 1.62% to 8.27%, in which the HPLC-OPA method with water extraction showed the lowest value at 1.62%. Inhibition rates of the free amino acids in Doenjang were greatest with an addition of NaCI at a 1% concentration.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1780-1784
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• 2006

Cloud point extraction was used to extract mefenamic acid (MF) from human urine, and spectrofluorimetry and spectrophotometry were used to analyze extracted MF. The variables affecting extraction and phase separation, i.e. HCl and Triton X-114 concentration, temperature and time of equilibration, were optimized. Under the experimental conditions used the limit of detection for extraction of 25 mL of sample was 0.006 and 0.045 mg $L^{-1}$, with relative standard deviations of 2.52 and 1.45% (n = 5) for spectrofluorimetric or spectrophotometric methods, respectively. Good recoveries in the range of 95-107% were obtained for spiked samples. The proposed methods were applied to the determination of MF in human urine.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.510-513
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• 2017

Patchouli oil extraction in general is still using conventional methods that require a long time of extraction. It is therefore necessary to develop extraction methods to obtain patchouli oil with optimum yield and quality. One of the new methods, which has been successfully developed, is microwave hydrodistillation (MHD). In addition to optimizing the extraction process of patchouli oil, this study also used microwave air-hydrodistillation (MAHD). Based on the research results, extraction using MAHD method can produce higher yield of patchouli oil when compared using MHD method. Also, based on the results of the analysis by GC-MS, extraction using MAHD method can produce quality of patchouli oil that is almost the same when compared using MHD method. This is supported by the results of the analysis by GC-MS, which showed that the content of patchouli alcohol is the main component of patchouli oil, and is almost the same for patchouli oil extracted using MHD method (26.32%) and MAHD method (25.23%).

• Analytical Science and Technology
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• v.16 no.2
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• pp.134-142
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• 2003

Comparison of a microwave-assisted extraction with sonication extraction was performed for arsenic speciation in fish tissue with chromatographic separation and inductively coupled plasma mass spectrometry detection. The detection limits of arsenicals with ultrasonic nebulizerand cross-flow nebulizer were shown to be similar. The arsenicals investigated were arsenobetaine (AsB), arsenite [As(III)], dimethylarsine acid (DMA), monomethylarsonic acid (MMA), arsenate [As(v)], and phenylarsonic acid (PAA). Quantitative extraction of arsenicals from dogfish muscle, DORM-2, standard reference material of NRCC (National Research Council of Canada) was achieved using 50% (v/v) methanol-water in both extraction methods. Extraction efficiency of arsenobetaine in both methods is greater than 82% with RSDs on replicates of less than 5%. The concentrations of AsB determined in extract of microwave assisted extraction and sonication methods were $14.18{\pm}0.42mg\;kg^{-1}$ and $13.54 {\pm}0.84mg\;kg^{-1}$, respectively. And the concentrations of DMA were $0.45{\pm}0.06mg\;kg^{-1}$ and $0.44{\pm}0.06mg\;kg^{-1}$, respectively.

• Food Science and Preservation
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• v.23 no.2
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• pp.233-238
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• 2016

A effect of extraction methods, including stirrer extraction method (SE), ultrasonification extraction method (USE), reflux extraction method (RE), autoclave extraction (AE) and low temperature high pressure extraction (LE) method on the antioxidative and antimicrobial activities of ethanol extracts of Oenothera biennis was investigated. The extraction yield (46.33%), total polyphenol (463.05 mg GAE/g) and flavonoid (71.71 mg RHE/g) content of Oenothera biennis extract obtained by RE were higher than those from other extraction methods. The antimicrobial activity of Oenothera biennis extract was only observed against Bacillus cereus among other tested organisms (Bacillus cereus, Staphylococcus aureus, Escherichia coli and Salmonella Typhimurium). Oenothera biennis obtained by RE showed the best DPPH radical scavenging ability (74.40%), ABTS radical scavenging ability (65.29%), reducing power (1.370 ($OD_{700}$)) and ferrous ion chelating ability (90.14%) compared with other tested extraction methods tested. The RE method was the most efficient method for extracting crude antioxidant and antimicrobial substances from Oenothera biennis. These results suggested that Oenothera biennis obtained by RE could be used as a bioactive and functional material in the food industry.