• Analytical Science and Technology
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• v.32 no.5
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• pp.163-172
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• 2019

Methamphetamine (MA) is currently the most abused illicit drug in Korea and its major metabolite is amphetamine (AP). As MA exist as two enantiomers with the different pharmacological properties, it is necessary to determine their respective amounts in a sample. Thus a chiral stationary phase liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for identification and quantification of d-MA, l-MA, d-AP, and l-AP in human urine. Urine sample ($200{\mu}L$) was diluted with pure water and purified using solid-phase extraction (SPE) cartridge. A $5-{\mu}L$ aliquot of SPE treated sample solution was injected into LC-MS/MS system. Chiral separation was carried out on the Astec Chirobiotic V2 column with an isocratic elution for each enantiomer. Identification and quantification of enantiomeric MA and AP was performed using multiple reaction monitoring (MRM) detection mode. Linear regression with a $1/x^2$ as the weighting factor was applied to generate a calibration curve. The linear ranges were 25-1000 ng/mL for all compounds. The intra- and inter-day precisions were within 3.6 %, while the intra- and inter-day accuracies ranged from -5.4 % to 11.8 %. The limits of detection were 2.5 ng/mL (d-MA), 3.5 ng/mL (l-MA), 7.5 ng/mL (d-AP), and 7.5 ng/mL (l-AP). Method validation parameters such as selectivity, matrix effect, and stability were evaluated and met acceptance criteria. The applicability of the method was tested by the analysis of genuine forensic urine samples from drug abusers. d-MA is the most common compound found in urine and mainly used by abusers.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.845-854
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• 2009

There has been increased concern regarding the release of antibiotics to different environmental compartments due to the possibility of the development of antibiotic resistant bacteria. However, limited information is available regarding the occurrence, fate, and transport of antibiotics in Korea in both the aqueous phase and in solid phases such as sediment and soil. Therefore, this study was conducted to monitor the concentration of released antibiotics in surface water, sediment, and soil adjacent to a cattle manure composting facility in Korea. Specifically, the following six antibiotics were monitored: tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC), sulfamethazine (SMT), sulfamethoxazole (SMX), and sulfathiazole (STZ). To extract and quantify the antibiotics from different environmental compartments, solid phase extraction (SPE) and high performance liquid chromatography mass spectrometry (HPLC/MS) techniques were adopted. The concentration of the six antibiotics ranged from below the detection limit (BDL) to 0.71 ${\mu}g$/L in surface water, from BDL to 27.61 ${\mu}g$/L in sediment, and from 0.12 to 157.33 ${\mu}g$/L in soil. In addition, higher concentrations of antibiotics were observed in surface water and sediment at locations closer to the composting facility indicating that composting is the source of the antibiotics found in the environment. Furthermore, higher concentrations of antibiotics were observed in the solid phase (sediment and soil) than the aqueous phase. These findings indicate that the possibility of antibiotic resistant bacteria is increased because such bacteria are more stable in the solid phase. Overall, longterm monitoring of the aqueous phase and solid phase is necessary to gain a better understanding of the impact of antibiotics from source on the environment in Korea.

• 한국환경농학회:학술대회논문집
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• 2011.07a
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• pp.281-281
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• 2011

• Analytical Science and Technology
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• v.21 no.4
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• pp.259-271
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• 2008

The analytical method of extracting compounds from human blood to examine accumulated organochlorine pesticides (OCPs) has been widely used the traditional liquid-liquid extraction (LLE) method and solid-phase extraction (SPE) method, yet these methods have certain limitations in purification and usafe of a large amount of sample. In order to overcome the se problems reside in these, solid-phase microextraction (SPME), known as a highly efficient extration method with less samples and relatively simple, was employed to collect 18 different kinds of OCPs in blood as extraction method in this study. To optimize extraction method, we examine various experimental SPME-parameters such as adsorption (fiber type, adsorption time, adsorption temperature, salting out effect), and desorption (desorption time, desorption temperature etc.). From the experimental results, the optimal conditions are as follows: fiber was polyacrylate with $85{\mu}m$, adsorption time was for 5 min, adsorption optimum temperature was at $280^{\circ}C$, and salting out effect was NaCl with 0.1 g. MDL, precision and accuracy was in the ranges of 0.05~0.20 ng/mL, 5.59~13.39%, respedively, and accuracy was -0.5% ~24.5% for all OCPs.

• YAKHAK HOEJI
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• v.57 no.2
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• pp.87-94
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• 2013

An analytical methodology based on solid-space extraction (SPE) with with Bond Elut Certify cartridge (Varian, 130 mg) has been developed for the qualification and quantitation of strychnine in blood. After the elution layer was evaporated, the residue was reconstituted with methanol for GC/MS. Internal standard was used 10 mg/l dextromethorphan. Strychnine is a potent central nervous stimulant and convulsant, and an alkaloid found in seeds of Strychnos nux-vomica. It was used therapeutically to improve circulation and muscle tone in oral or intramuscular doses of 0.05~8 mg. The fatal dose of strychnine for humans is 50~100 mg. A man was found dead lying curled up the corner of the large room in a roof house after the fire fighter opened a locked door inside to put out the fire. The postmortem blood and gastric contents were analyzed for toxicological testing. Strychnine and brucine were detected using GC/MS first in gastric contents extracts. The contents of strychnine was 0.083 mg/l in heart blood, 0.088 mg/l in peripheral blood and 4.0 mg/kg in gastric contents, respectively. Method validation was carried out in terms of linearity, accuracy, precision (intraday, interday) in blood. The assay is linear over 0.05~10 mg/l ($r^2$=0.999). Limit of detection (LOD) and limit of quantitation (LOQ) in blood were determined 0.02 mg/l (S/N=3) and 0.07 mg/l (S/N=10), respectively. Accuracy (bias%) of strychnine with 0.1, 1 and 10 mg/l was 12.0% (n=6), 9.3% (n=6) and 6.9% (n=6), respectively. Intraday precision (CV%) of strychnine with, 0.1, 1 and 10 mg/l were 6.4%, 10.4%, 1.2% (n=6), respectively. Interday precision (CV%) of strychnine with 0.1, 1 and 10 mg/l over three days were 24.0%, 18.5%, 13.8% (n=18), respectively. Relative recovery with 0.1, 1 and 10 mg/l (in blood) were 114.9%, 99.3% and 87.4% (n=6), respectively. The described method can be applied in forensic toxicology to determine strychnine in blood samples.

• Analytical Science and Technology
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• v.23 no.4
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• pp.395-404
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• 2010

A multi-residual method using gas chromatography coupled with mass spectrometry (GC/MS/ MS) was developed for the analysis of 105 pesticides. This method was tested on lemons, beans and other vegetables. The pretreatment of these pesticides was performed by liquid-liquid partition followed by cleanup with solid phase extraction cartridge (SPE Florisil), after acetonitrile extraction from matrices and sodium chloride (15 g) addition. The recovery ranged from 71.1% to 126.0% except for azinphosmethyl, famoxadone, fenamidone, flufenoxuron and triadimefon in lemons and from 72.5% to 124.5% in bean. In lemon, the limit of detection (LOD) and limit of quantification (LOQ) were 0.001~150 ng/ mL and 0.004~500 ng/mL, respectively.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.597-605
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• 2009

Algae bloom occurred in reservoir in summer can cause taste and odor in water and disturb the flocculation and sedimentation processes in water treatment plant and cause sand filter plugging. It was also reported that microcystins, anatoxin and saxitoxin released from cyanobacteria had acute toxic effects on liver and nervous system. For these reasons, many advanced countries inclusive of WHO set the guideline for these toxins and cyanotoxins have been managed with regular monitoring in Korea as well. However, complex sample preparation steps such as a solid phase extraction (SPE) and derivatization are required with an existing analysis method with HPLC. We needed to improve an analysis method for low extraction efficiency and long sample preparation time. In this study, we have established a new LC/MS/MS method which can simultaneously determine 6 cyanotoxins (Microcystins-LR, Microcystins-RR, Microcystins-YR, Anatoxin-a, Saxitoxin, Neosaxitoxin) with only simple filtration step. When $75{\mu}L$ filterated sample was injected onto the LC-MS/MS, the recovery ranged from 86% to 112% and the MDL was $0.025{\sim}0.581{\mu}g/L$. We can make the MDL be lower than the guideline ($1{\sim}3{\mu}g/L$) of advanced countries with simple preparation.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1029-1034
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• 2000

A suitable method of sample treatments to minimize the analytical interferences was presented in order to determine bisphenols [bisphenol F (BPF), bisphenol A (BPA), bisphenol F diglycidyl ether (BFDGE), and bisphenol A diglycidyl ether (BADGE)] in various canned beverages coated with epoxy resin by the reversephase high performance liquid chromatography (RP-HPLC) equipped with a fluorescence detector and the gas chromatography with mass selective detection. The recovery test of bisphenols was performed using 1, 5, and 10 ${\mu}g/L$ bisphenols spiked beverages with the combined technique of the solid-phase extraction (SPE) and the liquid-phase extraction (LPE). Both BPA and BADGE showed quite adequate resolutions in HPLC-chromatograms. The recoveries of BPA obtained by LPE with diethyl ether were higher than those obtaind with methylene chloride on coffee, shikhye and fruit juice. For cola and tea, the recoveries of BPA obtaind by SPE were higher than those by LPE with diethyl ether. The recoveries of BADGE were less than those of BPA for all beverage samples treated by either SPE or LPE method. In survey of bisphenols for eighteen commercial canned beverage samples, BPA contents of coffee, cola, tea, shikhye, and fruit juice were in the range of $1.3{\sim}11.6,\;0.5{\sim}0.9,\;1.0{\sim}1.3,\;2.4{\sim}7.9$, and $3.0{\sim}3.4\;{\mu}g/L$, respectively, but there was no detection of BPA in beer sample.

• Food Science and Preservation
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• v.21 no.3
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• pp.381-387
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• 2014

Food irradiation is one of the successful modern techniques used to preserve food. However, it needs very careful control. Detection of irradiated food is of prime importance to facilitate global trade and consumer assurance, choice, and protection. This study was performed to evaluate the radiation-induced hydrocarbon content of dried squid and octopus by e-beam irradiation. The samples were collected from supermarkets all over South Korea and irradiated with an e-beam at 0, 1, 3, 5, 7, and 10 kGy doses. Lipids were extracted with soxhelt, and the hydrocarbons induced with irradiation were separated via solid phase extraction (SPE) and identified via gas chromatography mass spectrometry (GC/MS). The major induced hydrocarbons in the irradiated dried squid and octopus were 1-tetradecene and pentadecane derived from palmitic acid and 1-hexadecene and heptadecane from stearic acid. The concentration of hydrocarbons differed from the composition of the fatty acid at the same radiation and increased according to the level of the radiation dose. The hydrocarbons induced by e-beam irradiation, including 1-tetradecene, 1-hexadecene, and heptadecane, were confirmed to have been the irradiation marker compounds. Therefore, they can be used to distinguish the e-beam-irradiated dried squid and octopus from the non-irradiated ones.

• Analytical Science and Technology
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• v.31 no.1
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• pp.39-46
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• 2018

Carbaryl and seven organophosphorous pesticides were analyzed simultaneously using on-line solid phase extraction (on-line SPE) coupled with liquid chromatography tandem mass spectrometry (LC/MS/MS). The target pesticides are Carbaryl, Methyl demeton, Fenitrothion, Malathion, Parathion, Phenthoate, Diazinon, and EPN. This method includes the direct injection of $500{\mu}L$ in the water sample, a 15 min separation period using a rapid resolution liquid chromatography system with on-line SPE, and detection through electrospray ionization (ESI) positive mode. The percentage of recovery of all pesticides ranged from 85.3 % to 100 %. This method showed an accuracy of ${\geq}90.0%$, possessing limits of detection and quantification within 0.05 to $0.28{\mu}g/L$ and 0.16 to $0.89{\mu}g/L$, respectively. The correlation coefficients (r) for the calibration curves within a range of 0.5 to $8.0{\mu}g/L$ were higher than 0.99. The evaluation results showed the efficacy of the method for all contents, and no pesticides were detected in the water quality sample.