• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.130-137
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• 2020

BACKGROUND: Mefentrifluconazole and triticonazole are the triazole fungicides. The maximum residue levels for agricultural products need to be set up. Therefore, development of the official analytical method for determination of mefentrifluconazole and triticonazole residues from agricultural crops was necessary due to safety management, and then a simultaneous analytical method was developed for the determination of mefentrifluconazole and triticonazole in agricultural crops. METHODS AND RESULTS: Samples were extracted using acetonitrile and purified using dispersive solid phase extraction, and then detected with liquid chromatograph-tandem mass spectrometry (LC-MS/MS). Matrix-matched calibration curves (0.0025-0.25 ㎍/mL) were linear into a sample extract with r²>0.99. For validation, the recovery test was carried out at three fortification levels (LOQ, 10 LOQ and 50 LOQ) from agricultural samples. The results for mefentrifluconazole and triticonazole ranged between 92.3 to 115.3% and 91.4 to 108.5%, respectively and RSD (relative standard deviation) values were also below 6.0%. Furthermore, inter-laboratory was conducted to validate the method. CONCLUSION: All values were corresponded with the criteria ranges requested by both the CODEX (CAC/GL 40-1993, 2003) and MFDS guidelines (2016). Therefore, the proposed method can be used as an official analytical method for determination of mefentrifluconazole and triticonazole (triazole fungicides) in the Republic of Korea.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.312-318
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• 2020

A method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for neonicotinoid pesticide analysis in agricultural products. Four compounds (imidacloprid, clothianidin, acetamiprid, thiacloprid) were extracted with acetonitrile from agricultural products and cleaned up by NH₂ solid-phase extraction procedure, and eluted with 0.1% formic acid in methanol/dichloromethane (5/95, v/v). The limit of detection and quantification were 0.0001-0.0005 mg/kg and 0.001 mg/kg, respectively. The mean recoveries of neonicotinoid pesticide from agricultural products were in the range of 90.7-100.9% and 94.4-99.8%, as spiked at 0.2 mg/kg and 0.02 mg/kg, respectively. This validation satisfied the national criteria for pesticide analytical methods. In summary, The present method is fast, precise and sensitive enough for the Positive List System (PLS), and we conclude that the method is also suitable for neonicotinoid pesticide determination in a wide range of agricultural products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.7
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• pp.822-832
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• 2017

This study analyzed contents of organic acids, free sugars, and volatile flavor compounds by type of Jerusalem artichoke (Helianthus tuberosus L.). Organic acids in dried Jerusalem artichoke were mainly composed of malic acid, citric acid, and succinic acid. Sucrose, fructose, and glucose were the major sugar components of dried Jerusalem artichoke. Free sugars were more abundant in the white colored sample than in the purple colored sample. In contrast, purple colored sample contained more organic acids than the white colored one. Volatile compounds in Jerusalem artichoke were investigated using the solid-phase micro-extraction method of gas chromatography/mass spectrometry. A total of 117 volatile compounds were identified in Jerusalem artichoke, and chemical classification was as follows: 5 acids, 13 alcohols, 19 aldehydes, 12 hydrocarbons, 15 ketones, 8 miscellaneous, 27 pyrazines, and 18 terpenes in all samples. Terpene was the most abundant in Jerusalem artichoke, and ${\beta}$-bisabolene was the main component in terpenes. The second most common compound was aldehyde, and hexanal was the highest. Pyrazines were the most abundant in the roasted samples, and 2,5-dimethyl-3-ethylpyrazine was present at the highest level, followed by 2,5-dimethylpyrazine. Compared with purple samples, main compounds contained in white samples were aldehydes and hydrocarbons, whereas the major compounds in purple samples were terpenes and alcohols.

• YAKHAK HOEJI
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• v.55 no.2
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• pp.106-115
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• 2011

Systematic toxicological analysis (STA) means the process for general unknown screening of drugs and toxic compounds in biological fluids. In order to establish STA, in previous study we investigated pattern of drugs & poisons in autopsy cases during 2007~2009 in Korea, and finally selected 62 drugs as target drugs for STA. In this study, rapid and simple drug identification and quantitative analytical program by gas chromatography-mass spectrometry(GC-MS) was developed. The in-house program, "DrugMan", consisted of modified chemstation data analysis menu and newly developed macro modules. Total 55 drugs among 62 target drugs were applied to this program, they were 14 antidepressants, 8 anti-histamines, 5 sedatives/hypnotics, 5 narcotic analgesics, 3 antipsychotic drugs, and etc. For calibration curves, fifty five drugs were divided into four groups of range considering their therapeutic or toxic concentrations in blood specimen, i.e. 0.05~1 mg/l, 0.1~1 mg/l, 0.1~5 mg/l or 0.5~10 mg/l. Standards spiked bloods were extracted by solid-phase extraction (SPE) with trimipramine-D3 as internal standard. Parameters such as retention times, 3 mass fragment ions, and calibration curves for each drug were registered to DrugMan. A series of identification, semi quantitation of target drugs and reporting the results were performed automatically. Calibration curves for most drugs were linear with correlation coefficients exceeding 0.98. Sensitivity rate of DrugMan was 0.90 (90%) for 55 drugs at the level of 0.5 mg/l. For standard spiked bloods at the level of 0.5 mg/l for 29 drugs, semi quantitative concentrations were ranged 0.36~0.64 mg/l by DrugMan. If more drugs are registered to database in DrugMan in further study, it will be useful tools for STA in forensic toxicology.

• Food Science and Preservation
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• v.13 no.1
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• pp.108-114
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• 2006

This study was conducted to determine the volatile flavor compositions of the essential oil and the headspace of Capsella bursa-pastoris Medicus. Essential oil and headspace from the plant were extracted by simultaneous steam distillation extraction (SDE), and solid-phase microextraction(SPME) methods, respectively. Seventy-two compounds including 28 hydrocarbons, 4 aldehydes, 6 ketones, 16 alcohols, 4 esters, 8 acids, and 6 miscellaneous ones were identified in the leaf essential oil extracted by SDE method Sixty-eight compounds including 26 hydrocarbons, 2 aldehydes, 6 ketones, 17 alcohols, 4 esters, 6 acids, and 7 miscellaneous ones were identified in the root essential oil. According to the instrumental analyses the essential oil, phytol ($21.12\%$ in leaves, $20.94\%$ in roots) was the most abundant compound Alcohols, esters, and acids were main groups of the essential oil. On the other hand, thirty-eight compounds including 18 hydrocarbons, 3 aldehydes, 3 ketones, 9 alcohols, 2 esters, 3 miscellaneous ones were identified in the leaf headspace by SPME. In root headspace, thirty-three compounds including 16 hydrocarbons, 2 aldehydes, 1 ketone, 9 alcohols, 3 esten;, and 2 miscellaneous ones were identified. Hydrocarbons($44.02\%$ in leaves, $56.98\%$ in roots) were the main components of the headspace of Capsella bursa-pastoris Medicus.

• Food Science and Preservation
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• v.20 no.2
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• pp.207-214
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• 2013

This study was conducted to investigate changes in the main volatile flavor components of oriental melon during the process of alcohol fermentation via SPME (solid phase micro extraction). The flavor components of oriental melon were shown to have mainly included melon and green flavors. The green flavor was identified to be nonanal, 1-butanol, 1-octen-2-ol and benzene, and its relative concentration was shown to be 16.66%. The nonanal concentration was shown to have been reduced among the green-flavor components, but no significant change in remaining components was observed. Mainly, sweet flavor tended to increase, and the relative concentration of benzene was particularly shown to have increase by 25.58%, accounting for the highest relative concentration. The amount of green-flavor components, except for 1-butanol, was shown to have significantly decrease after alcohol fermentation. Then, no component of green-flavor, which causes an offensive smell, was found during fermentation and aging. Meanwhile, the volatile flavor components, which are consist of acids, were shown to have been produced during alcohol fermentation. In particular, octanoic acid, which causes off-flavor, was shown to be 60.99%, a very high relative concentration during the aging stage. In addition, acetic acid with a pungent sour flavor tended to be produced. A further study on the improvement of flavor in the production of oriental melon wine is required.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1477-1483
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• 1999

In order to retain or remove the flavor components of onions, this study was performed to investigate the effect of seaweeds and adsorbents on volatile flavor components of onion juice by testing a sensory evaluation, measuring the amount of pyruvate and thiosulfinate, and investigating the changes of volatile components by SPME/GC. The main flavor compounds in raw onion juice were dipropyl tetrasulfide, 1-propenyl propyl trisulfide, methyl propyl trisulfide, dipropyl trisulfide. Volatile flavor compounds in onion juice treated with tangleweed, brown-seaweed, laver and celite showed a relatively decreasing tendency compared to untreated onion juice, but most of volatile flavor compounds in onion juice treated with activated charcoal and ${\beta}-cyclodextrin$ were removed. The result of the sensory evaluation with various materials for masking onion flavor showed a significant difference at the p<0.05 level. The amount of pyruvate and thiosulfinate treated with tangleweed, brown-seaweed, laver and celite showed little difference compared to untreated onion juice, but the amount of pyruvate and thiosulfinate treated with activated charcoal and ${\beta}-cyclodextrin$ decreased largely compared to untreated onion juice. As a result of the study, onion juice treated with tangleweed, brown-seaweed, laver and celite showed the effect of preserving the pungent taste and masking the onion flavor. Activated charcoal and ${\beta}-cyclodextrin$added to onion juice might have a role in removing the onion flavor by adsorbing volatile flavor compounds in onion.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.355-361
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• 2009

Polycyclic aromatic hydrocarbons (PAHs) are environmental carcinogenic compounds that arise by several means including food processing methods such as smoking and direct drying and cooking. This study examined the concentration of PAHs in sesame oils with various roasting temperatures (190, 220 and $250^{\circ}C$), methods (direct heating vs. indirect hot air heating), and times (5, 10, 15, 20 and 25 min). The PAHs in the sesame oils were analyzed using liquid-liquid extraction and solid-phase clean up (Florisil), followed by HPLC with fluorescence detection. According to the results, mean levels of total PAHs increased when the sesame oils were roasted at increasing temperatures and times. The sesame oil roasted at $250^{\circ}C$ for 25 min had the highest mean value of total PAHs (4.66 ${\mu}g$/kg). The results of this study suggest that the indirect hot air roasting method decreased PAH formation during sesame oil processing.

• Analytical Science and Technology
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• v.26 no.3
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• pp.174-181
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• 2013

Pyrifluquinazon is classified with a quinazoline insecticide that regulates food intake by controling the feeding behavior acting on the endocrine or nervous system of pests such as aphids and white fly. To keep safety on pyrifluquinazon residues in agricultural commodities a simple, accurate and rapid analytical method was developed and validated using high performance liquid chromatograph (HPLC-UVD). The pyrifluquinazon residues acidified with 1% formic acid in samples were extracted with acetonitrile and partitioned with hexane subsequently to dichloromethane then purified with silica solid phase extraction (SPE) cartridge. The purified samples were detected using HPLC-UVD. The method was validated using apple and pear spiked with pyrifluquinazon at 0.02, 0.05 and 0.1 mg/kg and hulled rice, pepper, soybean at 0.05 and 0.1 mg/kg. Average recoveries were 70.5~107.9% with relative standard deviation less than 10%. The result of recoveries and overall coefficient of variation of a laboratory results in Gwangju regional FDA and Daejeon regional FDA was followed with Codex guideline (CODEX CAC/GL 40). This method is appropriated at pyrifluquinazon residues determination and will be used as official method of analysis.

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.22-27
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• 2011

Nonylphenols are toxic compounds classified as endocrine disruptors. We investigated the nonylphenols clean-up procedures for the contamination control in the quantitative analysis. In this research we analyzed the residual nonylphenols in the solvent and the SPE cartridges. First, at the analysis of HPLC grade solvents (n-hexane, diethyl ether, ethyl acetate and its mixture), diethyl ether was confirmed the residue as 0.963 ${\mu}g/mL$, and we eliminated the contaminant through the distillation with $CaH_2$, Second, at the analysis of SPE cartridges (silica gel and Florisil), all products were showed the residue at 0.046~13.0 ${\mu}g/mL$, but unfortunately the residue in the cartridge were not easily removed with referenced methods in all tested SPE cartridges except in silica gel SPE cartridge with glass ware.