• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.162-167
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• 2013

An analytical method for the simultaneous determination of pencycuron in agricultural products was established by using GC-NPD. The method was validated through the guidelines of linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy and precision. The calibration curve of pencycuron was linear over the concentration range of 0.02-2 mg/kg with correlation coefficient of above 0.9999. The limits of detection and quantification were 0.005 and 0.02 mg/kg. Mean recoveries of pencycuron for each sample were 79.6-107.5% at the level of 0.02 mg/kg and 86.4-112.1% at the level of 0.2 mg/kg and 84.0- 104.9% at the level of 1 mg/kg. Relative standard deviation (RSD) in recoveries were all less than 5%. The intra- and inter-day precision (RSD) were 1.6-3.0% and 5.3-11.5%, respectively. The result of validation indicated that this method was accurate and sensitive assay.

• Journal of Food Hygiene and Safety
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• v.30 no.4
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• pp.366-371
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• 2015

This work was conducted to apply the multi class pesticide multiresidue method for determining the use of hexaconazole in the agricultural products using GC-NPD. The multi class pesticide multiresidue method results were validated for the assay of hexaconazole by using linearity, accuracy, precision, limit of detection and quantitation. The linearity in the concentration ranged from 0.025 to 5.0 mg/L ($R^2$ > 0.999). Lettuce recoveries ranged from 89.42% to 94.15% with relative standard deviations below 7.78%, for spiking levels from 0.04 to 4.0 mg/kg. The limit of detection was 0.04 mg/kg, and the limit of quantitation was 0.11 mg/kg. The intra- and inter-day precisions were 2.42~3.49% and 4.90~7.78%, respectively. We suggested that the multi class pesticide multiresidue method for determining hexaconazole was highly accurate and reproducible, and it will be used as a routine analysis in agricultural products.

• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.193-198
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• 2017

Scutellaria baicalensis, Eleutherococcus senticosus, and Angelica sinensis have been used as raw materials for health functional foods. This study was conducted to develop a novel method to analyze levels of baicalin (Scutellaria baicalensis), eleutheroside E (Eleutherococcus senticosus), and ligustilide (Angelica sinensis) simultaneously in health functional foods. The methanol extracted samples were analyzed and quantified via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the positive ion mode and the negative ion mode using multiple reaction monitoring. Standard calibration curves confirmed linearity with the correlation coefficient ($r^2$) of > 0.99 at $100-2000{\mu}g/mL$ concentration range. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of $13.0{\sim}35.2{\mu}g/L$ and $39.3{\sim}106.7{\mu}g/L$, respectively. The recovery results ranged between 91.4~109.9% at 3 different concentration levels with relative standard deviations (RSDs) less than 5%. The proposed analytical method was characterized with high accuracy and acceptable precision. The new method would be an effective tool to analyze baicalin, eleutheroside E, and ligustilide simultaneously in raw materials of health functional foods.

• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.107-116
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• 2013

Polar pesticides like pymetrozine (log $P_{ow}$: -0.18) are known to be difficult to analyze. The analytical method of pymetrozine using hydromatrix included in the official method of KFDA was uncommon and provided ambiguous evidence to confirm both the identity and the quantity. Therefore, precise single residue analytical method was developed in representative crops for using liquid-liquid extraction (LLE). The pymetrozine residue was extracted with methanol from 11 representative crops which comprised apple, blueberry, broccoli, cabbage, cherry, crown daisy, hulled rice, Korean cabbage, potato, rice and watermelon. The extract was purified serially by liquid-liquid extraction (LLE) and silica solid phase extraction (SPE). For rice and hulled rice samples, n-hexane partition was additionally adopted to remove nonpolar interferences, mainly lipids. The residue levels were analyzed by HPLC with DAD, using $C_8$ column. LOQ (limit of quantitation) of pymetroizinie was 1 ng (S/N > 10) and MQL (method quantitation limit) was 0.01 mg/kg. Mean recoveries from 11 crop samples fortified at three levels (MQL, 10 ${\times}$ MQL and 50 ${\times}$ MQL) in triplicate were in the range of 83.1~98.5% with coefficients of variation (CV) of less than 10%, regardless of sample type, which satisfies the criteria of KFDA. The method established in this study could be applied to most of crops as an official and general method for analysis of pymetrozine residue.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.4
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• pp.333-340
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• 2019

This study attempted to eatablish a high performance liquid chromatography (HPLC) analysis method for the determination of avicularin, quercitrin as a part of the quality control for the development of functional cosmetic materials from Astilbe chinensis extract. HPLC was performed on a Capcell Pak C₁₈ MGII column with a gradient elution of 0.05% (v/v) trifluoroacetic acid (TFA) and acetonitrile at a flow rate of 1.0 mL/min at 30 ℃. The analyte was detected at 254 nm. The HPLC method was performed in accordance with the international conference on harmonization (ICH) guideline (version 4, 2005) of analytical procedures with respect to specificity, precision, accuracy, and linearity. The limits of detection and quantitation of avicularin and quercitrin were 0.094 and 0.285 mg/mL, 0.031 and 0.095 mg/mL respectively. Calibration curves showed good linearity r² > 0.99990 for avicularin and r² > 0.99994 for quercitrin. Precision of analysis was satisfied with less than 0.59% for avicularin and 0.63% for quercitrin. Recoveries of quantified compounds ranged from 100.97 to 101.77% for avicularin and 100.18 to 100.32% for quercitrin. These result indicated that the established HPLC method is very useful for the determination of marker compounds in A. chinensis extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1221-1226
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• 2016

This study investigated changes in the S-allyl-L-cysteine (SAC) content of garlic using different cooking methods. Methods for determining SAC were validated by determining specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy using an high-performance liquid chromatography-fluorescence detection system. Results showed high linearity in the calibration curve with a coefficient of correlation ($R^2$) of 0.9999. The LOD and LOQ values for SAC were 0.15 and $0.47{\mu}g/mL$, respectively. The relative standard deviations for intra- and inter-day precision of SAC were less than 5%. The recovery rate of SAC was in the range from 97.35% to 97.47%. The SAC content of raw garlic was 2.77 mg/g, and there was no significant difference in SAC content according to blanching and microwave treatment. However, SAC content upon boiling and autoclaving at $110^{\circ}C$ and $121^{\circ}C$ increased from 3.50~9.16 mg/g, 6.52~16.21 mg/g, and 14.15~50.24 mg/g with increasing cooking temperature and time, respectively.

• 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.

• Bulletin of Food Technology
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• v.21 no.2
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• pp.49-54
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• 2008

농산물 중 잔류농약을 보다 쉽고 효율적으로 분석 할 수 있는 다성분 동시분석 방법에 따라서 UPLC-PDA을 이용하여 기기조건에 따른 검출한계 및 정량한계를 식품별 최저 MRL과 비교하여 유효성을 알아보고 회수율을 통하여 방법의 재현성을 조사한 결과 다음과 같다. 41종의 농약에 대한 검량선은 직선성이 우수하였으며 검출한계 $0.005{\sim}0.109mg/kg$으로 나타났으며 정량한계 는 $0.018{\sim}0.363ppm$으로 나타났다. Cycloprothrin 등의 경우처럼 검출기의 감응도가 최저 MRL 기준을 초과하는 농약에 대한 보완으로는 검출감도가보다 우수한 UV 검출기 등의 병행 활용이 필요하다. 회수율에 따른 재현성은 쌀의 경우 첨가 농도 0.4 mg/kg 일때 $62.09{\sim}99.58%$로 편차범위는 $1.03{\sim}13.92%$ 얻을 수 있었다.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.201-206
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• 2012

Benzo(a)pyrene is a polycyclic aromatic hydrocarbons (PAHs) whose metabolites are mutagenic and highly carcinogenic and is listed as a Group 1 carcinogen by the IARC. It has been found at variable concentrations in several foods and is associated with several factors during the process including contaminated raw materials, exposure of environment, and procedure of process or cooking. In this study, benzo(a)pyrene in 45 oriental medicines were determined by HPLC/FLD. The calibration curves of benzo(a)pyrene was linear over the concentration range of 0.5~40 ng/mL with correlation coefficient of above 0.999. The limit of detection (LOD) and limit of quantitation (LOQ) of benzo(a)pyrene were 0.04 and 0.10 ${\mu}g/kg$. Benzo(a)pyrene in 3 samples out of 45 samples was not detected. The level of benzo(a)pyrene in 26 (57.7%), 8 (17.8%) and 7 (15.6%) samples was 0.1~0.5, 0.5~1.0 and 1.0~5.0 ${\mu}g/kg$, respectively. Especially, content of benzo(a)pyrene in Coptis Rhizome is the highest (5.97 ${\mu}g/kg$). In conclusion, these results suggest that could be applied to fundamental study and guideline on drying condition to decrease content of benzo(a)pyrene in oriental medicine.

• Korean journal of applied entomology
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• v.60 no.3
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• pp.263-268
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• 2021

The venom of honeybees (Apis mellifera L.) is used to treat many diseases because of its anti-inflammatory and analgesic effects. Bee venom consists of several biologically active molecules and exhibits remarkable anti-cancer effects. However, biological amines, which exhibit diverse functionality such as anti-inflammatory and antibacterial effects, have not been previously reported in bee venom. In this study, we determined the content of putrescine in bee venom by using ultra-performance liquid chromatography. The specificity, accuracy, and precision of the assay were assessed, and the assay validated. The linearity of the putrescine assay was r ≥ 0.99, indicating a moderate level of putrescine in the bee venom. The limit of detection and limit of quantification were both 0.9 ㎍/mL, while the rate of recovery was 96.4%-99.9%. The relative standard deviation (RSD) of the intra-day precision and inter-day precision of the putrescine assay were 0.16% - 0.23% and 0.09% - 0.36%, respectively, with the RSD ≤ 5% indicating excellent precision. Thus, the linearity, limit of detection, limit of quantification, and recovery rate of the putrescine assay were satisfactory. The analysis of the bee venom showed that the putrescine content was 3.1 ± 0.09 mg/g. This study provides fundamental data on putrescine content in bee venom, which will prove useful in further studies of its bioactivity.