• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.241-246
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• 2007

Purpose: $[^{11}C]6-OH-BTA-1$ ([N-methyl-$^{11}C$]2-(4'-methylaminophenyl)-6-hydroxybenzothiazole, 1), a -amyloid imaging agent for the diagnosis of Alzheimer's disease in PET, can be labeled with higher yield by a simple loop method. During the synthesis of $[^{11}C]1$, we found the formation of by-products in various solvents, e.g., methylethylketone (MEK), cyclohexanone (CHO), diethylketone (DEK), and dimethylformamide (DMF). Materials and Methods: In Automated radiosynthesis module, 1 mg of 4-aminophenyl-6-hydroxybenzothiazole (4) in 100 l of each solvent was reacted with $[^{11}C]methyl$ triflate in HPLC loop at room temperature (RT). The reaction mixture was separated by semi-preparative HPLC. Aliquots eluted at 14.4, 16.3 and 17.6 min were collected and analyzed by analytical HPLC and LC/MS spectrometer. Results: The labeling efficiencies of $[^{11}C]1$ were $86.0{\pm}5.5%$, $59.7{\pm}2.4%$, $29.9{\pm}1.8%$, and $7.6{\pm}0.5%$ in MEK, CHO, DEK and DMF, respectively. The LC/MS spectra of three products eluted at 14.4, 16.3 and 17.6 mins showed m/z peaks at 257.3 (M+1), 257.3 (M+1) and 271.3 (M+1), respectively, indicating their structures as 1, 2-(4'-aminophenyl)-6-methoxybenzothiazole (2) and by-product (3), respectively. Ratios of labeling efficiencies for the three products $([^{11}C]1:[^{11}C]2:[^{11}C]3)$ were $86.0{\pm}5.5%:5.0{\pm}3.4%:1.5{\pm}1.3%$ in MEK, $59.7{\pm}2.4%:4.7{\pm}3.2%:1.3{\pm}0.5%$ in CHO, $9.9{\pm}1.8%:2.0{\pm}0.7%:0.3{\pm}0.1%$ in DEK and $7.6{\pm}0.5%:0.0%:0.0%$ in DMF, respectively. Conclusion: The labeling efficiency of $[^{11}C]1$ was the highest when MEK was used as a reaction solvent. As results of mass spectrometry, 1 and 2 were conformed. 3 was presumed.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.49-61
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• 2017

The study was conducted for safety evaluation of 208 kinds of residue pesticides on 200 dried agricultural products, which are distributed in Gwangju. The method of monitoring was the second of Multi Class Pesticide Multi-residue Methods in Korean Food Code, and GC-ECD, GC-NPD, GC-MSD, and LC-MS/MS were used as evaluation equipment to analyze. The residue level in pesticides were 15.5% (31 of 200 samples) and 4 samples exceeded MRLs. 4.5 mg/kg of pyraclostrobin (MRL; 3.0 mg/kg) was detected in red pepper, 1.49 mg/kg of chlorpyrifos (MRL; 0.13 mg/kg) in daikon leaves, 38.26 mg/kg of pyridalyl (MRL; 0.25 mg/kg) in pepper leaves, 0.98 mg/kg of chlorpyrifos (MRL; 0.05 mg/kg), respectively. Pesticides were found on the 15 samples among the 21 samples of red pepper which is a fruit vegetable, and this resulted in high detection rate of 71%. In addition, pesticides were detected on chwinamul, shitake, siler divaricata, daikon leaves and others within MRLs. The frequent detected kinds of pesticides were insecticide (47.6%), fungicide (33.3%), acaricide (14.3%), nematicide (4.8%) in the order named, and pesticides were methoxyfenozide > pyraclostrobin > azoxystrobin, chlorantraniprole > novaluron, trifloxystrobin in frequent order.

• Korean Journal of Environmental Agriculture
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• v.36 no.4
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• pp.279-287
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• 2017

BACKGROUND: Many farmers who cultivate the strawberries for export have used agricultural chemicals which MRL (Maximum Residue Limits) of main export target countries or simultaneous multi-residue analysis in Korea have not been established. Among them, the cyenopyrafen and cyflumetofen were selected and applied to this study to determine the PHI (pre-harvest interval) which is appropriate to the PLS (Positive List System) criterion (0.01 mg/kg) and to investigate the residual amounts in the samples. In addition, Fifty pesticides were monitored to check up whether it is suitable or not for main export target countries. METHODS AND RESULTS: Cyenopyrafen and cyflumetofen were spayed out to the strawberries. Samples for residual analyses were taken for maximum 60 days. After sampling, they were extracted by the QuEChERS method and analyzed using the LC-MS/MS. Cyenopyrafen and cyflumetofen were detected in a range of 0.0106~2.6517 mg/kg and of 0.0005~1.4480 mg/kg, respectively. From this results, they were found to be suitable for PLS concentration after 30 or 45 days after spray. In addition, they were detected in most samples that were selected at random. Their concentrations were higher than the PLS criterion in the maximum twenty samples. Twelve of pesticides unsuitable for main export target countries have been detected in the monitoring of simultaneous multi-residue analysis. The result indicates they are unsuitable for export since they excesses over PLS criterion. CONCLUSION: The monitoring result showed it is necessary to establish the pesticide standards of safe use suitable for the PLS criterion. In addition, it is considered continues management and inspection are needed to solve problems caused by unsuitable pesticides in export strawberries.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.453-462
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• 2011

This study was carried out to survey the residual characteristics of pesticides and assess their safety. Nineteen agricultural commodities, collected from wholesale and traditional markets in Cheongju. Nineteen agricultural commodities including perilla leaves were collected from the markets on October 29th, 2010. Total 240 pesticides which can be analyzed by multiresidue analysis method by GLC and HPLC were monitored and the pesticides detected were confirmed by GC-MSD and LC-MS. Five pesticides, alachlor, bifenthrin, endosulfan, procymidone and triflumizole, were detected from five samples, such as welsh onion, leek and celery in case of wholesale market and perilla leaves and welsh onion in case of traditional market. Detection rate of 13.2% was obtained as a result of pesticide analysis but 2.6% of the pesticides detected exceeded their maximum residue limits. The estimated daily intakes (EDIs) and maximum permissible intakes (MPIs) of the pesticides detected were less than 26% and 0.05% of their acceptable daily intakes (ADIs) respectively, representing that residue levels of the pesticides detected would be safe.

• Journal of Plant Biotechnology
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• v.47 no.1
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• pp.78-89
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• 2020

Tomato fruit quality is determined by the contents of various functional metabolites in addition to fruit appearance. To develop tomato cultivars with higher amounts of functional compounds, an efficient quantification method is required to identify the natural variations in the compounds in the tomato germplasm. In this study, we investigated tomato varieties, which included 23 inbred lines and 12 commercial F₁ cultivars, for their contents of seven watersoluble vitamins (vitamin C, vitamins B1, B2, B3, B5, B6, and B9) and five polyphenolic compounds (quercetin, rutin, kaempferol, myricetin, and naringenin chalcone). The results of high performance liquid chromatography and liquid chromatography-mass spectrometry showed that vitamin C and naringenin chalcone were the major water-soluble vitamins and polyphenolic compounds, respectively, and their abundance was highly variable depending on the cultivar. By contrast, the contents of vitamin B1, quercetin, and kaempferol were lowest among the cultivars. With regard to the relationship between metabolic compounds and fruit characteristics, a significant association was found in fruit size, indicating that cherry tomato varieties contain higher amounts of the compounds compared to large fresh-type varieties. However, no direct association was detected in fruit color, except for naringenin chalcone. The results of this study provide new insights on the quantification of metabolic compounds and the selection of breeding materials, which are prerequisites for the development of functional tomato varieties.

• Korean Journal of Pharmacognosy
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• v.49 no.4
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• pp.312-321
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• 2018

Recently, consumer demand for functional cosmetics containing natural ingredients has been greatly expanded. To develop the natural cosmetic materials, we selected 3 plants, Chrysanthemum zawadskii Herbich (CZ), Perilla frutescens (L.) Britton var. acuta Kudo (PF), and Rosa multiflora Thunberg (RM) which showed high total flavonoid contents (TFC), total polyphenol contents (TPC), and strong DPPH radical scavenging effect. We determined astragalin, chlorogenic acid, and rosmarinic acid as a marker compound for quantitative analysis of the content of each material and standardization of the quality standards and manufacturing standards through LC/MS analysis. HPLC-DAD was used to simultaneously analyze these marker components of three natural product complexes (Mix) and to validate the analytical method through experiments such as linearity, accuracy and precision. The detection wavelengths were set at 210, 265, and 330 nm. The detected 3 compounds from extract of CZ, PF, RM showed significant linearity ($R^2${\geq_-}$0.9947). The limit of detection (LOD) of chlorogenic acid, astragalin and rosmarinic acid were $8.29{\mu}g/ml$, $2.28{\mu}g/ml$, and $27.00{\mu}g/ml$, respectively. The limit of quantification (LOQ) of chlorogenic acid, astragalin and rosmarinic acid were $25.11{\mu}g/ml$, $6.92{\mu}g/ml$, and $81.83{\mu}g/ml$, respectively. The contents of the three indicators of Mix were 19.82-24.71 mg/g of chlorogenic acid, 43.80-46.02 mg/g of astragalin, and 46.33-48.57 mg/g of rosmarinic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.220-228
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• 2017

Effects of extraction methods on reducing concentrations of pro-oxidants (total iron and protein) of salmon was determined. For development of the extraction process, the effectiveness of several extraction methods was determined and compared, including heat treatment (60, 80, and $100^{\circ}C$), ion exchange and carboxymethyl (CM)-cellulose column chromatography, and ultrafiltration (UF). Protein, total iron, and anserine contents of salmon extracts were 23.64 mg/mL, $16.20{\mu}g/mL$, and 5.47 mg/mL in non-heated extracts, 7.40 mg/mL, $2.32{\mu}g/mL$, and 5.20 mg/mL in heated extracts at $60^{\circ}C$, 7.64 mg/mL, $1.20{\mu}g/mL$, and 5.21 mg/mL at $80^{\circ}C$, and 7.04 mg/mL, $0.68{\mu}g/mL$, and 4.04 mg/mL at $100^{\circ}C$, respectively. Heating and UF decreased contents of protein and total iron, whereas only UF slightly decreased anserine content. Application of the primary ion exchange method increased the content of anserine up to 16%. Protein and total iron contents by the primary ion exchange method decreased by 70 and 98%, respectively. Secondary ion exchange (CM-cellulose) treatment after primary ion exchange and UF resulted in lower anserine content than the primary ion exchange method. However, the content of impurities (protein, total iron) was lower than in all other salmon extracts. Therefore, primary ion exchange, UF, and secondary ion exchange method were the best extraction processes in this study.

• Journal of Food Hygiene and Safety
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• v.31 no.3
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• pp.186-193
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• 2016

An analytical method was developed for the determination of oxathiapiprolin in agricultural commodities. Oxathiapiprolin is a new oomycide (fungicide of piperidinyl thiazole isoxazoline class) which controls downy mildew in cucurbits caused by Pseudoperonospora cubensis (oomycete plant pathogen). Agricultural commodities were extracted with acetonitrile and partitioned with dichloromethane to remove the interference, adjusting pH between 9 and 10 by 1 N sodium hydroxide. After purification by silica SPE cartridge to clean up the interference of organic compounds, they were finally quantified by HPLC-UVD (high performance liquid chromatograph ultraviolet detector) using a wavelength at 260 nm and confirmed by LC-MS (liquid chromatograph mass spectrometer) in electro-spray ionization positive ion mode. The standard calibration curve was linear with coefficients of determination ($r^2$) 1.00 over the calibration ranges (0.025-2.5 mg/L). Recoveries were ranged between 86.7 to 112.7%, with relative standard deviations less than 10% at three concentration levels (LOQ, 10LOQ, and 50LOQ) performing five replicates. The overall results were determined and estimated according to the CODEX guidelines (CAC/GL40). The proposed method for determination of oxathiapiprolin residues in agricultural commodities can be used as an official method.

• Journal of Nutrition and Health
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• v.43 no.6
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• pp.588-596
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• 2010

Most nutrients taken by pregnant women are secreted into their breast milk. Food contains choline together with betaine, and in human body choline is oxidized to betaine which transfer methyl group. The aim of the study was to estimate the concentrations of choline and betaine in breast milk of Korean lactating women and the choline and betaine intakes of their infants. Total choline, free choline and betaine concentrations in breast milk of some lactating women living in Daejon Metropolitan city were analyzed every month by using HPLC-MS and enzymatic method during the first five months. Total choline concentrations of breast milks were 157.64 mg/L (1.52 mmol/L), 157.83 mg/L (1.52 mmol/L), 165.99 mg/L (1.60 mmol/L), 153.67 mg/L (1.48 mmol/L), 145.05 mg/L (1.39 mmol/L) by month after delivery for five months. The concentrations of total choline and free choline in breast milks were not significantly changed for the five months while the betaine concentrations gradually decreased. Daily intake of total choline of the infants appears to be adequate for the infant's requirement according to the US DRI; 124.6 mg/d, 120.9 mg/d, 126.5 mg/d 104.1 mg/d from 2nd to 5th month after birth. Free choline and betaine intakes of the infants were not significantly changed during the four months except showing decrease in betaine intake per kg body weight. Choline intakes of the infants more correlated with choline concentrations of the breast milks (r = 0.982, p = 0.000) than intake amount of the breast milk (r = 0.414, p = 0.028). These results suggest that the choline intake of Korean breast-fed infants appears to be adequate and the intake could be affected by the choline concentration of the breast milk.