• YAKHAK HOEJI
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• v.54 no.6
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• pp.429-440
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• 2010

HS-SPME-GC/MS was studied and optimized for the determination of 17 orgarnophosphorous pesiticides (OPPs: chlorpyrifos, chlorpyrifos-methyl, demeton-s-methyl, diazinon, dimethoate, EPN, fenitrothion, fenthion, malathion, methidathion, monocrotophos, parathion, phenthoate, phosphamidon, sulfotep, terbufos, triazophos) in blood. Optimum SPME parameters were selected: choice of SPME fiber (85 ${\mu}m$ polyacrylate), pH effect (0.5 N HCl), salt effect ($Na_2SO_4$, 0.2 g; 20%), headspace incubation temperature ($80^{\circ}C$), headspace incubation time (1 min), headspace adsorption time (30 min) and GC desorption time (2 min). These parameters were optimized using HS-SPME autosampler coupled with gas chromatography-mass spectrometry (GC-MS). Method validation was carried out in terms of linearity, limit of detection (LOD), limit of quantitation (LOQ) and recovery in blood. The assay was linear over 0.5~5.0 mg/l ($r^2$=0.955~1.000). Limit of detection (LOD) and limit of quantitation (LOQ) in blood were determined 0.03~0.3 mg/l (S/N=3) and 0.1~1.1 mg/l (S/N=10), respectively. Relative recovery with 0.5, 1 and 5 mg/l (in blood) were 90.8%, 98.5% and 94.1%, respectively. This method will be applied to the determination of the orgarnophosphorous pesticides in postmortem blood. The proposed protocol can be an attractive alternative to be used in routine toxicological analysis.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.721-727
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• 1998

An analytical method for simultaneous and rapid determination of organophosphorus, organochlorine, carbamate, and pyrethroid pesticides in polished rice was developed. The analysis is performed by gas chromatograph with mass selective detector (GC/MSD) in selected ion monitoring (SIM) mode. Pesticides were extracted from samples with acetone by automated Soxhlet apparatus and this extract was evaporated to dryness for the analysis. The residue was dissolved in hexane, followed by a treatment with a Sep-Pak florisil catridge. Pesticides were positively confirmed by GC/MS, retention times, and ion ratios. This analytical method allows a rapid, reliable, and a good recovery of hydrophilic pesticides. Except far captafol, captan, dichlofluanid and dichlorvos, recoveries of 42 pesticides were over 70%.

• Journal of Food Hygiene and Safety
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• v.14 no.2
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• pp.140-145
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• 1999

Analytical method for preservatives in food was developed using gas chromatography/mass spectrometry (GC/MS). Propionic acid, sorbic acid, benzoic acid, ethyl salicylate, ethyl p-hydroxy benzoate, iso-propyl p-hydroxy benzoate, n-propyl p-hydroxy benzoate, iso-butyl p-hydroxy benzoate, n-butyl p-hydroxy benzoate, p-hydroxy benzoic acid and dehydro acetic acid were extracted from cooling beverage with diethyl ether. The polar hydroxyl and carboxyl groups of food preservatives were derivatized with N-methyl-N-tert-butyldimethylisilyl-trifluoroscetamide (MTBSTFA) to form the corresponding tert-bytyldimethyl-silylated derivatives, and submitted to GC/MS analysis. The mass spectra of the derivatives were investigated for the selection of monitoring ions for multi-residue analysis of 11 preservatives by GC/MS. The macro program was also developed for the qualitative analysis of these preservatives in food.

• Analytical Science and Technology
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• v.22 no.3
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• pp.210-218
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• 2009

A gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed and validated for simultaneous determination of amphetamine derivatives and norketamine in human hair. Preparation of hair involves external decontamination, mechanical pulverization, incubation and extraction prior to instrumental analysis. The samples were derivatized using heptafluorobutyric anhydride, and analyzed by GC-MS/MS. The linear ranges were 0.05-20.0 ng/mg for the analytes except for 3,4-methylenedioxyamphetamine, with good coefficients of determination ($r^2$ >0.998). The intra-day and inter-day precisions were within 10.7% and 8.5%, respectively. The intra-day and inter-day accuracies were between -1.6 and 17.0% and -2.6 and 10.5%, respectively. The limits of detections for each analyte were lower than 0.007 ng/mg, while recoveries were 75.9-100.9%. When the method was applied to hair samples obtained from suspected drug abusers, the concentrations in hair samples were 0.97-19.30 ng/mg for methamphetamine and 0.14-2.56 ng/mg for amphetamine.

• Journal of the Korean Society of Tobacco Science
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• v.15 no.2
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• pp.174-184
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• 1993

This is to investigate the methodology for the simultaneous determination of Wk, mk and TSNA using gas chromatography(GC) in combination with chemiluminescence detector, thermal energy analyzer(TEA) . The simultaneous analysis has been estimated by evaluating tobacco. The TEA was linked to GC equipped with non -polar SPB -5 fused silica capillary column which was introduced into the ceramic pyrolysis tube by the point of 16cm from the end of TEA. Quantification was carried out by internal standardization with WDPA after calibration of retention times and response factors with authentic nitrosoamines. It was demonstrated that WDPA was most preferable as internal standard for the simultaneous analysis. The recoveries of the internal standard were in the range of 83∼96% . Nitrosoamines in this method were detected with determination limit of 0.1ng and was made by a straight line in calibration curve by TEA response. The suitability of nitrosoamines extraction in tobacco leaf was investigated. It was most suitable to extract nitrosoamines from tobacco leaves with 0.01 M NaOH within a period of 8 hours. Thimerosal as an antibacterial agent was added to NaOH solution to prevent artifactual formation. The fractionation and the purification of nitrosoamines form alkaline extracts were conveniently performed using Extrelut multilayer column and dichloromethane. Reproducible and reliable results were obtained for the determination of nitrosamines in a relatively short time compared to previous known method. TSNA contents in burley were about 4 times higher as those in the fluecured tobacco.

• Analytical Science and Technology
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• v.21 no.2
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• pp.84-92
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• 2008

A method for the determination of trace amount of caffeine in urine and various drink samples using hollow fiber-liquid phase microextraction (HF-LPME) and capillary gas chromatograph/nitrogen phosphorus detector (GC/NPD) has been established. HF-LPME method has been optimized with respect to several experimental parameters including the effects of the hollow fiber length, extraction solvent, stirring mode, pH and salt concentration for the determination of caffeine from aqueous samples. The correlation coefficient of calibration curve for caffeine was 0.9994. The average recovery was 102%(n=3). The established method is feasible for the determination of trace amounts of caffeine in several aqueous sample. The limit of detection (LOD) and the limit of quantitation (LOQ) have been found to be 2.5 and 10 ng/mL, respectively. The established HF-LPME method for the analysis of caffeine from aqueous sample can be used for the determination of biological, food and environmental samples.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.222-226
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• 2013

A simple and sensitive analytical method was developed using gas chromatograph with electron capture detector (GC-ECD) and gas chromatograph-mass spectrometer (GC-MS) for determination and identification of chloropicrin. Because of small molecular weight and high volatile properties of chloropicrin, analytical method was developed utilizing headspace extraction and direct injection to the GC. The developed method was validated using hulled rice sample spiked with chloropicrin at different concentration levels, 0.1 and 0.5 mg/kg. Average recoveries of chloropicrin (using each concentration three replicates) ranged 77.7~79.3% with relative standard deviations less than 10% and calibration solutions concentration in the range $0.005{\sim}0.5{\mu}g/mL$, and limit of detection (LOD) and limit of quantification (LOQ) were 0.004 and 0.01 mg/kg, respectively. The result showed that developed analytical methods was successfully applied to detect a small amount of chloropicrin in hulled rice.

• Analytical Science and Technology
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• v.14 no.2
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• pp.180-190
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• 2001

Oder-active compounds are complex in a sample. These compounds are usually analyzed by GC or GC/MSD while such analytical measurement can quantify specific volatile organic compounds, it has limitations in identifying odor-active compounds. To resolve this problem, GC-Sniffing or GC-Olfactometry method has been attempted. In this study, GC/FID/Olfactometry system was developed. This system can simultaneously sniff and detect GC effluents by traditional GC combined with human olfactory system. The time gap between FID and ODP response was dependent on the kinds and concentrations of chemicals and panels, with more volatile, stronger and shorten breath cycle panel showing narrow time gap. Thus, clear relationship between FID and ODP should be considered to identify the odor-active compounds.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.195-203
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• 2015

Quintozene, pentachloronitrobenzene (PCNB) is a contact fungicide for control of soilborne phytopathogenic fungi during cultivation of diverse crops. It was introduced to agricultural use around 1930's as a substitute for mercurial disinfectants. Although quintozene had been first registered in Korea on 1969. However, now it was banned to use due to its high residue levels in selected harvest products. Also, high possibility is expected that the residue may be contained in imported agricultural commodities as it is still used widely over the world. Therefore, this study was conducted to establish a determination method for quintozene residue in crops using GC/ECD/MS. Quintozene residue was extracted with acetonitrile from representative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, green pepper, and apple. The extract was diluted with saline water, and n-hexane partition was followed to recover quintozene from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The quintozene was quantitated by GLC with ECD, using a DB-1 capillary column. The crops were fortified with quintozene at 3 levels per crop. Mean recoveries ranged from 79.9% to 102.7% in five representative agricultural commodities. The coefficients of variation were less than 4.3%. Quantitative limit of quintozene was 0.004 mg/kg in representative five crop samples. A GC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of quintozene in agricultural commodities.

• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.199-208
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• 1994

Analytical methods for the determination of the derivatives of the herbicide (${\pm}$)-2-(4-chloro-2-methylphenoxy)propionic acid (MCPP) by capillary column gas chromatography with mass spectrometer (GC-MS) and electron-capture detection (GC-ECD) were studied. A successful procedure was introduced for the ester preparation using $H_2SO_4$, as the catalyst and the alcohol 2,2,2-trichloroethanol (TCE) or 2,2,2-trifluoroethanol (TFE). The identificaiton and elucidation of MCPP by GC-MS spectrometry following the esterification with diazomethane, $BF_3$/methanol, $H_2SO_4$/methanol, TCE, TFE, or pentafluorobenzyl bromide (PFB) were carried out. A comparison of the response-sensitivities among those MCPP esters was made with GC-ECD. Although the methylation product of MCPP was confirmed by GC-MS, its low sensitivity to the ECD limited the detection of MCPP. TCE, TFE, and PFB derivatization methods resulted in a high rate of MCPP esterifications and very sensitive ECD molecular responses. Based on efficiency, convenience, worker safety, and least sample contamination, TFE esterificaiton was considered as the superior method for MCPP analysis to the other methods of derivatization. An accurate method is described for quantifying MCPP in soil leachates by GC-ECD at very low concentrations without the requirement of a complicated clean-up process. As a result, MCPP residues at concentrations of less than $0.1{\mu}g$ in 100ml soil leachate were detected.