• Analytical Science and Technology
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• v.16 no.6
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• pp.483-487
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• 2003

Amitrole is well-known as a non-selective herbicide and it is able to cause contamination of driking water as well as pollution of ground water and surface water. However, it is difficult to extract from water because it has a high solubility for water whereas a low solubility for general organic solvents. This method is described for the determination of amitrole in water samples by GC/MS. After evaporation of 10 mL water sample by a vacuum evaporator, amitrole was derivatized with isobutyl chloroformate (iso-BCF) on room temperature for 15~20 min. As a result, the sensitivity for GCfMS was improved as N-isobutoxycarbonyl amitrole derivative was formed. The linearity of the calibration curve showed good as 0.997. The recoveries were obtained more than 94.9% and relative standard deviations were less than 2.8% at $1.0{\mu}g/L$, $10.0{\mu}g/L$ and $100.0{\mu}g/L$. The limit of detection showed $0.1{\mu}g/L$ with a signal-to-noise ratio (S/N) of 3.

• Analytical Science and Technology
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• v.25 no.5
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• pp.307-312
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• 2012

To perform inhalation toxicity test by using experiment animals, we set up an analytical method to monitor didecyldimethylammonium chloride (DDAC) in aerosol nebulized into inhalation chambers by ion chromatography. DDAC was adsorbed by XAD-2 resin and analyzed with conductivity detector. Recovery of DDAC desorbed by acetonitrile from XAD adsorbent was 87.8%. The method detection limit (MDL) and the limit of quantitation (LOQ) were 2.97 ${\mu}g/m^3$ and 8.92 ${\mu}g/m^3$, respectively. Repeatability was calculated as RSD 7.8% in the range of 0~20 ${\mu}g/mL$. Time needed to analyze a sample was less than 5 minutes. Therefore, the analysis of DDAC by ion chromatography was practically useful in monitoring DDAC in inhalation chambers with rapidity and sensitivity manner to perform inhalation toxicity test using experimental animals.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.146-151
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• 2012

BACKGROUND: This study was conducted to develop analytical method for picoxystrobin in agricultural commodities using GC/ECD and GC/MS. METHODS AND RESULTS: Each steps of analytical method were optimized for determining picoxystrobin residues in various agricultural commodities. The developed methods include acetone extraction, n-hexane/saline water partition and florisil column chromatography for analysis of all samples (apple, potato, green pepper, hulled rice and soybean), and in addition to these steps, solid phase extraction (SPE) was used for analysis of green pepper and n-hexane/acetonitrile partition was used for analysis of hulled rice and soybean. The instrumental conditions were tested for quantitation in GC/ECD and for confirmation in GC/MS. Recovery was in the range of 86~109% with RSD ${\leq}$10.2% and the quantitation limits (LOQ) of method were 0.025 mg/kg in all agricultural commodities. CONCLUSION: The result showed that the developed method can be used to determine picoxystrobin residue in agricultural commodities.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.63-66
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• 2017

BACKGROUND: The phenol concentrations in water samples were determined using gas chromatography after derivatization of the analyte to phenyl acetate followed by extraction using a large volume of solvent. However, this procedure requires an additional purification step and is not analytically efficient. METHODS AND RESULTS: In this study, phenol was first extracted from an acidified water sample using ethyl acetate and then acetylated using acetic anhydride in the presence of a small amount of water and $K_2CO_3$. The derivative was extracted using 1mL of n-butyl acetate. One microliter of the extract was analyzed by GC-MS without further purification. The calibration curve showed good linearity with the $r^2$ value of 0.9968. The method detection limit and the limit of quantitation were estimated to be $0.18{\mu}g/L$ and $0.56{\mu}g/L$, respectively. Repeatability (RSD, n=3) and recovery (n=3) were 9.1%-4.3% and 90.6%-110.5%, respectively. The concentrations of phenol in a few samples of stream water were distributed in the range of $2.51-7.51{\mu}g/L$. CONCLUSION: This method is simpler and faster to implement than those currently utilized and shows high analytical reliability. It can be applied to the quantitative determination of phenol concentrations in surface water and groundwater samples.

• Korean Journal of Environmental Biology
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• v.34 no.3
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• pp.216-221
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• 2016

Level and distribution of fourteen polycyclic aromatic hydrocarbons (PAHs) in the agricultural water samples collected in the waterways located in Gyeonggi and Gangwon, Korea were determined for monitoring and risk assessment. A simplified, fast but effective extraction and clean-up methods combined with gas chromatography tandem mass spectrometry (GC-MS/MS) was employed to measure the concentration of the target compounds. The extraction of the analytes of interest in water sample (10 mL) was performed with acetonitrile (10 mL) and the salt. To purify the target PAHs, the clean-up procedure was employed with 2 mL tubes of dispersive solid phase extraction. The optimized method was validated with recoveries, method detection limit (MDL), accuracy and precision. Good recoveries for each PAHs at 10 and $25{\mu}g\;L^{-1}$ were achieved (60 to 110%, with RSD <20%) with linearity (>0.99). MDL for all the analytes was achieved with $0.2{\mu}g\;L^{-1}$. GC-MS/MS results showed that concentration of phenanthrene in the water samples from Gyeonggi (20 sites) ranged from 0.82 to $2.56{\mu}g\;L^{-1}$ and from Gangwon (15 sites) ranged from 0.83 to $1.62{\mu}g\;L^{-1}$. Other PAHs were not found in the water samples but the continuous monitoring for these areas were required.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.88-92
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• 2007

Isopropylthioxanthone(ITX) is used as a photoinitiator In UV-cured inks, triggering the radical polymerization of the acrylic component of such inks and thus causing the liquid ink film to cure. Recently ITX was detected in carton packed food in Italy. In order to cope with risk issues of overseas and acquire monitoring data on ITX, we have established the method using HPLC/FLD for ITX analysis after reviewing parameters of the analytical methods. Limit of detection (LOD) and limit of quantification (LOQ) were 0.02 ppb and 0.1 ppb, and linearity and RSD (%) were 0.9991 and 1.09, respectively. We have investigated ITX levels migrated to food on 87 commercial products packed in carton and ITX was not detected any food. Therefore it is supposed that UV-cured ink containing ITX as photoinitiator is not currently used in printing of carton pack in Korea.

• Journal of Food Hygiene and Safety
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• v.30 no.2
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• pp.173-177
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• 2015

Rosa canina L. is health functional food materials that can help to temporarily relieve symptoms of arthritis. This study has been conducted to develop and validate analytical methods for hyperoside of Rosa canina L.. Methods based on HPLC with ultraviolet detection (UVD) were established through instrumental analytical conditions, and the examination of data, such as domestic and foreign reliable methods and journals. HPLC UVD analysis using Capcell Pak $C_{18}$ MG II column at 353 nm was determined on test through the column, mobile phase. The validation has been performed on the method to determine linearity, accuracy, limits of quantification (LOQ) and repeatability for hyperoside. The method showed high linearity in the calibration curve at a coefficient of correlation ($R^2$) of 0.999, and the LOQ was $0.393{\mu}g/mL$. Relative standard deviation (RSD) values of data from repeatability precision was between 0.6 and 2.6%. Recovery rate test at hyperoside scored between 98 and 99%. These results indicate that the established HPLC method is very useful for the determination of hyperoside in Rosa canina L. to develop a health functional material.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.277-281
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• 2011

A rapid and very sensitive high-performance liquid chromatography/atmospheric-pressure chemical-ionization mass spectrometry method to detect ethylenethiourea (ETU) fungicide residues in fruits was developed. Methylene chloride was used as the surface extraction solvent for the target component. Recovery rates improved when cysteine hydrochloride and sodium carbonate were added to product prior to fortification. The limits of detection and quantification were approximately 0.006 and 0.02 mg/kg, respectively, from mandarin oranges. Recoveries from mandarin oranges, oranges, bananas, and pears, spiked in the range of 0.05-0.5 mg/kg, averaged 80-100%. The proposed method was used to monitor the presence of ETU in commercial fruits purchased from different markets in Seoul, Korea. ETU was found in four orange peels and in three mandarin orange peel samples. The highest ETU residue levels were $73.6{\mu}g/kg$ and $29.8{\mu}g/kg$.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.632-636
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• 2010

The level of ${\gamma}$-aminobutyric acid (GABA) in pigmented rice was quantitatively and qualitatively determined by high pressure liquid chromatography/fluorescence detection (HPLC/FLD). In this study, the recovery rate and limit of detection (LOD) of GABA were 122.4${\pm}$2.4% and 0.23 ${\mu}g/g$, respectively. The geminating pigmented rice samples, which were harvested in Paju, Korea, were soaked in water at $18^{\circ}C$ for 20 hr. After soaking, the samples were germinated at $30^{\circ}C$ for about 24 hr. GABA content was highest (293.0 ${\mu}g/g$) in the germinated red rice. Furthermore, GABA levels in the germinated rice increased significantly by up to 11.1 and 24.7-fold as compared to non-germinated rice and milled rice, respectively. The GABA concentrations of non-germinated rice, with the exception of red rice, were significantly higher than those of milled rice by 7.6-20.6-fold.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.409-415
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• 2013

Post-harvest fungicide residue was measured in citrus fruits. Samples were collected from local markets in Seoul and analyzed using liquid chromatography coupled with mass spectrometry (LC-MS). LC-MS results were validated for the assay of pesticides by using linearity, accuracy, precision, and limits of detection and quantification. The linearity in the concentration ranged from 0.005 to 2.0 mg/kg ($R^2$ >0.999). Sample recoveries ranged from 80.2 to 98.3% with relative standard deviations below 4.0% for spiking levels from 0.01 to 1.0 mg/kg. The limits of detection ranged between 0.002 and 0.008 mg/kg, and the limits of quantification ranged between 0.006 and 0.027 mg/kg. The highest residue levels for carbendazim, thiabendazole, imazalil, and azoxystrobin in citrus fruits were 0.541, 0.958, 0.721, and 0.052 mg/kg, respectively. The pesticide residues found in citrus fruits were blow maximum residue limits (MRLs) and are not a serious public health problem.