• The Korean Journal of Physiology and Pharmacology
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• v.2 no.6
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• pp.779-786
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• 1998

A reversed-phase high-performance liquid chromatogrphy (RP-HPLC) has been developed to analyze the metabolites of arachidonic acid based on the specificities of ultraviolet absorption of these various metabolites and is sensitive to the nanogram level. This procedure makes it possible to extract complex mixtures of eicosanoids efficiently with a single step and to analyze them simultaneously by RP-HPLC from biological samples using octadesylsilyl silica extraction column and $PGB_2$ as an internal standard. The cyclooxygenase products {prostaglandin $(PG)D_2,\;PGE_1,\;PGE_2,\;PGF_{1{\alpha}},\;PGF{2{\alpha}},\;6-keto-PGF_{1{\alpha}},$ and thromboxane $B_2(TXB_2)}$ and lipid peroxidation product, isoprostanes, of arachidonic acid were monitored by one isocratic HPLC system at 195 nm wavelength. The lipoxygenase products ${leukotriene(LT)B_4,\;LTC_4,\;LTD_4,$ and 5-hydroxyeicosatetraenoic acid (5-HETE), 12-HETE, 15-HETE} were measured by another isocratic HPLC system at 280 nm for LTs and 235 nm for HETEs. This method provides a simple and reliable way to extract and assess quantitatively the final arachidonic acid metabolites.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.895-899
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• 2009

A new approach for the determination of acrylamide (AM) in foods by solid phase microextraction-gas chromatography (SPME-GC) was established. AM was bromized and transformed to 2-bromoacrylamide (2-BAM). 2-BAM was then extracted by a commercial SPME fiber, $75-{\mu}m$ Car/PDMS fiber, for GC detection. The influence of extraction and desorption parameters such as extraction temperature and time, stirring rate, desorption temperature, and time were studied and optimized. The mass concentration was proportional to the peak area of 2-BPA from 1.0 to 8,000 ${\mu}g/L$. The detection limit of the SPME-GC for 2-BAM was found to be 0.1 ${\mu}g/L$, and the recoveries and relative standard deviations for different food samples were 74.5 to 102.0%, and 4.2 to 9.1%, respectively. The presented method was applied to the determination of AM in fried foods.

• Analytical Science and Technology
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• v.26 no.5
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• pp.307-314
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• 2013

Selenium exists in various forms of chemical species. The activity and bioavailability is strongly dependent on its chemical form and concentration. Consequently the information on each selenium species and its concentration must be exactly determined for the food we take in. In this study, selenium species in seafood were separated and quantified by RP (reversed phase) HPLC (high performance liquid chromatography) coupled with ICP-MS (inductively coupled plasma mass spectrometry) using post-column isotope dilution. $^{79}Br$, which interferes on $^{80}Se$, has mostly been removed by solid phase extraction and then mathematical correction has been applied for the more accurate correction. The experimental result for CRM (certified reference material) DOLT-4 agreed well with the certified value but each selenium species could not be compared. SeCys (selenocysteine) and SeMet (selenomethionine) were the major species detected in seafood such as belt fish, spanish mackerel, and squid that have been serving as Korean diet. The concentrations found in Korean sea food for SeCys and SeMet were in the range of 0-661.6 mg/kg and 137.3-462.7 mg/kg, respectively.

• Archives of Pharmacal Research
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• v.17 no.4
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• pp.244-248
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• 1994

A stereoselective and sensitive high performance liquid chromatography using fluoresecence deterctor was examined for the determination of R(-) and S(+)-salbutamol in human plasma. Solid phase extraction method using silica as sorbent was used to extract salbutamol racemates from the plasma matrices. After fractionation and freeze-drying of the eluates containing salbutamol racemates, they were separated and quantified on a chirla stationary column. The detection limit of each enantiomer was 2 ng/ml in human plasma (S/N=3).

• Journal of Korean Society of Water and Wastewater
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• v.18 no.5
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• pp.628-637
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• 2004

In many drinking water treatment plants, chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of disinfection by-products (DBPs) such as haloacetonitriles (HANs), trihalomethanes (THMs), haloacetic acids (HAAs). In this study, headspace-solid phase microextraction (HS- SPME) technique was applied for the analysis of HANs in drinking water. The effects of experimental parameters such as selection of SPME fiber, the addition of salts, magnetic stirring, extraction temperature, extraction time and desorption time on the analysis were investigated. Analytical parameters such as linearity, repeatability and detection limits were also evaluated. The $50/30{\mu}m$-divinylbenzene/carboxen/polydimethylsiloxane fiber, extraction time of 30 minutes, extraction temperature of $20^{\circ}C$ and desorption time of 1 minute at $260^{\circ}C$ were the optimal experimental conditions for the analysis of HANs. The correlation coefficients ($r^2$) for HANs was 0.9979~0.9991, respectively. The relative standard deviations (%RSD) for HANs was 2.3~7.6%, respectively. Detection limits (LDs) for HANs was $0.01{\sim}0.5{\mu}g/L$, respectively.

• Journal of Environmental Science International
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• v.19 no.12
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• pp.1447-1454
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• 2010

In this study, the detection limits of lower fatty acids in air were investigated by using Dynamic SPME(Solid Phase Micro-Extraction), i.e. improved Head Space - SPME method(HS-SPME). This Dynamic SPME, called SPDE(Solid Phase Dynamic Extraction), is the analytical method for volatile compounds in air with the extraction by using a stainless steel needle of which inner surface is coated with adsorption material and following the gas chromatographic analysis by inserting the needle into a injection port of GC and subsequently, desorption of the volatile compounds into a gas-chromatographic column. Extraction was carried out by passing the sample air through the needle with a suction pump which has been used for a detection tube. The result of measurement for the 6 lower fatty acids showed that the detection limits ranged from 0.10 ppm to 0.44 ppm and the linear correlation coefficients were over 0.99. Relative standard deviations obtained from 5 analytical repetition of a ca. 1.6 ppm standard mixture were in the range of 1.87%~2.47%. This method has been shown to be a adequate for the measuring C2~C5 fatty acids in air in the concentrations of over several hundreds ppb.

• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.285-294
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• 2005

This study was conducted to investigate the extraction method for the determination of organochlorine, organophosphorus and synthetic pyrethroid pesticide residues in beef fat by gas chromatography-mass selective detector(GC-MSD). Twenty one pesticide residues in fat were determined using a simple and rapid procedure based on solid- phase extraction(SPE) clean-up cartridges with octadecyl $(C_{18})-bonded$ porous silica, florisil, $10\%$ deactivated florisil. a tandem $C_{18}$ and florisil and a tandem $C_{18}$ and $10\%$ deactivated florisil. Solvent-solvent extraction using acetonitrile was not satisfied to eliminate fat interference for pesticide residue analysis by GC-MSD, and the recoveries of the method in fat ranged from 16.2 to $57.3\%$ except DDT$(83.2\%)$. The recoveries of SPE methods using a tandem $C_{18}$ and Florisil was $59.6\~123.8\%$ except fenitrothion $(135.2\%)$. the SPE method was verified the satisfactory performance of pre-treatment for pesticide residues analysis in fat by GC-MSD. The efficiency of florisil deactivated with $10\%$ water has been not proved significantly on recoveries of pesticide residues in fat.

• Archives of Pharmacal Research
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• v.27 no.5
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• pp.539-543
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• 2004

An efficient analytical method was devised for the accurate L-muscone assay in aqueous samples. It involves solid-phase extraction of L-muscone in adsorption mode using XAD-4 as the sorbent and dichloromethane modified with 10% (v/v) methanol as the eluting solvent. The gas chromatographic analysis of the eluate residue dissolved in toluene on a DB-5MS capillary column provided complete resolution of L-muscone from the co-extracted interferences. The overall method showed excellent linearity ($r^2{\geq}$ 0.9994) in the range of 0.1 to 2.0 $\mu\textrm{g}$/mL with good intra- and inter-day precisions (% RSD = 2.5～7.3) and with high extraction recovery rates ($\geq$ 98.1 %). When the present method was applied to a L-muscone herbal drink product, the within-batch RE (%) in the labeled concentration (1.5 $\mu\textrm{g}$/mL) for the three randomly chosen bottles were -2.4, -1.3 and -3.3 with high precision (% RSD $\leq$ 3.1). The present method is considered to be suitable for quality control evaluation on liquid drinks and other complex formulations fortified with L-muscone.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2691-2696
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• 2013

The electronic cigarette (E-cigarette) is a battery-powered device that aerosolizes nicotine so that it is readily delivered into the respiratory tract. The analytical data regarding the substances present in E-cigarettes are very limited. The aim of this study was to measure the concentration of aldehydes-formaldehyde (FA), acetaldehyde (AA) and, acrolein (AL)-in 225 replacement liquid brands from 17 E-cigarette shops sold in the Republic of Korea by headspace solid-phase micro extraction and gas chromatography-mass spectrometry (HS-SPME GC-MS). The concentration range of FA and AA was 0.02-10.09 mg/L (mean = 2.16 mg/L, detected in 207 of 225 samples) and 0.10-15.63 mg/L (mean = 4.98 mg/L, detected in all samples), respectively. AL was not detected in any of 225 replacement liquids. FA and AA were originally present in almost all replacement liquids of electronic cigarettes.

• YAKHAK HOEJI
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• v.46 no.6
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• pp.392-397
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• 2002

A simple and sensitive high performance liquid chromatographic method to quantitate ursodeoxycholic acid in crude drug pharmaceuticals was investigated. Ursodeoxycholic acid react with 2-bromoacetyl-6-methoxynaphthalene (Br-AMN) in the presence of triethylamine to form highly fluorescent derivative. The derivatization procedure was performed at 7$0^{\circ}C$ and completed within 30 min. The optimal wavelength of the fluorescence detector are λ$_{ex}$=300 nm and λ$_{em}$ = 460 nm. The LOD of the ursodeoxycholic acid was 25 ng/mι based on the S/N =3, and the LOQ was 80 ng/mι based on S/N = 10. Crude drug pharmaceuticals pretreated by solid phase extraction (Sep-pak $C_{18}$ cartridge) which were shown very good separation and recovery values for the compound.d.