• 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 the Korean Chemical Society
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• v.60 no.2
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• pp.118-124
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• 2016

Parabens were commonly used for preventing the growth of microorganisms as preservatives in the pharmaceutical, cosmetic and food industry. Also, parabens are known endocrine disruptors because of their estrogenic effects on human. Parabens affect the endocrine system and show adverse effect such as, genital malformations, precocious puberty and testicular cancer in young children, infants and fetuses. In this study, we developed analytical method for four parabens (methyl paraben, ethyl paraben, propyl paraben, butyl paraben) in human breast milk which frequently consumed by newborn baby. The analytes were extracted using liquid-liquid extraction (LLE) after enzyme hydrolysis with protease and lipase, then quantitative analysis was performed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The method validation results were as follows; the linearity of calibration curves were excellent with coefficient of determinations (r²) higher than 0.999, the limit of detections (LODs) were 0.019~0.044 ng/mL, the accuracies were 85.3~105.9% and the precisions were lower than 10%. The average concentration ± standard deviation of parabens in ten human breast milk sample were MP 0.660 ± 0.519 ng/mL, EP 1.631 ± 2.081 ng/mL and PP 0.326 ± 0.320 ng/mL, and BP was not detected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.8
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• pp.952-956
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• 2017

An high performance liquid chromatography (HPLC) analysis method was developed for standard determination of coixol as a functional cosmetic material in Coix lachryma-jobi var. ma-yuen roots extract. HPLC was performed on a $C_{18}$ Unison US column ($4.6{\times}250mm$, $5{\mu}m$ column) using a gradient elution of 0.1% (v/v) trifluoroacetic acid and acetonitrile at a flow rate of 1.0 mL/min at $30^{\circ}C$. The analyte was detected at 290 nm. The HPLC method was validated in accordance with the International Conference on Harmonization guideline of analytical procedures with respect to specificity, precision, accuracy, and linearity. The limit of detection and quantitation were 0.07 and 0.25 mg/mL, respectively. Calibration curves showed good linearity ($R^2$>0.9995), and the precision of analysis was satisfied (less than 0.29%). Recoveries of quantified compounds ranged from 98.36 to 100.30%. This result indicates that the established HPLC method is very useful for the determination of a marker compound in C. lachryma-jobi var. ma-yuen roots extracts.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.1-5
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• 2015

This study aimed to simultaneously determine various carotenoids from different colored paprika using an ultra performance liquid chromatograph (UPLC) equipped with a HSS T3 column. Analysis was performed at 450 nm using gradient conditions with acetonitrile/methanol/methylene chloride (65/25/10) and distilled water. We improved the peak resolution and performed carotenoid analysis within 30 min. We qualitatively analyzed 11 carotenoids (neoxanthin, capsorubin, violaxanthin, capsanthin, zeaxanthin, lutein, ${\alpha}$-cryptoxanthin, ${\beta}$-cryptoxanthin, lycopene, ${\alpha}$-carotene, and ${\beta}$-carotene). For the validation of UPLC methods, we validated the precision and accuracy of capsanthin. Capsanthin showed good linearity ($R^2$=0.9998) in the concentration range of $1-200{\mu}g/mL$ with 2.4 and $7.2{\mu}g/mL$ of limit of detection (LOD) and limit of quantification (LOQ), respectively. The relative standard deviation (RSD) for intra- and inter-day precision was less than 3.83%. Recovery was in the range of 91.86-99.87%. We quantitatively analyzed carotenoid contents from 8 different colored paprika (red, orange, yellow, and green). The most abundant carotenoids were capsanthin in red paprika, and zeaxanthin in orange, yellow, and green paprika.

• Analytical Science and Technology
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• v.32 no.6
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• pp.252-261
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• 2019

Pyrrolizidine alkaloids (PAs) are a group of secondary metabolites that are produced by plants all over the world as a defense mechanism against herbivores. To date, over 660 PAs have been identified from more than 6,000 plant species that have been reported to be widely present in plants belonging to Asteraceae, Boraginaceae, and Fabaceae. This study describes an analytical method based on UPLC-MS/MS for the quantitation of 7 pyrrolizidine alkaloids (Lycopsamine, Echimidine, Retrorsine, Retrorsine N-oxide, Senecionine, Heliotrine, and Trichodesmine) in honey, and was applied to 84 honey samples for validation. Quantitation was performed based on a matrix-matched calibration to compensate for the matrix effect on the electrospray ionization. Good linear calibrations were obtained for all 7 PAs in the spiked honey samples (2.575-202.14 ㎍/kg; R² ≥ 0.998). The extraction recoveries for most of the PAs in the honey samples were in the range of 81 %-108 %. The analysis showed that 6 of the 84 honey samples were contaminated by the PAs with the mean total sum of PAs being 47.19 ㎍/kg, and the concentrations of the PAs were observed to be in the range of 1.76-202.1 ㎍/kg. The retronecine type compounds (Echimidine, Lycopsamine) were the most frequently found PAs in honey. These data provide useful information for the assessment of human risk posed by the consumption of honey contaminated PAs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1791-1795
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• 2014

The objective of this study was to compare two extraction methods for determination of vitamin K1 (phylloquinone) in vegetables. In addition, analytical method validation parameters such as accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), and linearity were calculated to ensure the method's validity. Vitamin K1 was quantified by reversed-phase HPLC using post-column derivatization and fluorescence detection ($Ex{\lambda}=243nm$, $Ex{\lambda}=430nm$). Higher analytical values were observed using solvent extraction compared to those from the enzyme extraction method. The results from the method validation showed high linearity in the calibration curve with a coefficient of correlation ($R^2$) of 0.9994. The LOD and LOQ were 0.1335 and 0.2784 ng/injection volume ($50{\mu}L$), respectively. The inter-day precision and inter-day precision were 2.0% and 2.1%, respectively. Overall recovery was close to 100% (n=5). The phylloquinone contents ranged from 9.42 to $1,212.57{\mu}g/100g$. Our study provides reliable data on the phylloquinone contents in commonly consumed vegetables in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1737-1741
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• 2014

An HPLC method for determination of naringin was developed to standardize it as a marker compound in Goheung yuzu extract as a functional health food. Optimum results were obtained by C-18 column chromatography using solvent mixtures (A: 0.5% acetic acid, B: acetonitrile) as the stationary phase and mobile phase. The method was fully validated and sensitive with a limit of detection (LOD) of 0.0218 mg/L and limit of quantification (LOQ) of 0.0661 mg/L. The method showed high linearity (coefficient of correlation=0.9986) and high accuracy, as recovery rates of naringin at concentrations of 1, 0.5, 0.1, 0.05 mg/mL were in the ranges of 95.74~98.25%, 97.67~101.01%, 97.33~104.64%, and 95.53~106.82%, respectively. Intra-day and inter-day variation, which are measures of method precision, were 1.39~1.95% and 0.17~1.49%, respectively. Therefore, the method could be used without modification for determination of naringin as a marker compound in Goheung yuzu extracts.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.496-507
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• 2020

Virus infections of apples result in lowered commercial qualities such as low sugar content, weakened tree vigor, and malformed fruits. An effective way to control viruses is to produce virus-free plants based on the development of an accurate and sensitive diagnostic method. In this study, real-time PCR assays based on SYBR Green I and TaqMan probes were developed for detecting ASGV, ASPV, and ApMV viruses. These methods can detect and quantify 10³ to 10¹¹ RNA copies/μL of each virus separately. Compared with methods with two different dyes, the SYBR Green I-based method was efficient for virus detection as well as for assay using the TaqMan probe. Field tests demonstrated that real-time PCR methods developed in this study were applicable to high-throughput diagnoses for virus research and plant quarantine.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.1-5
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• 2011

It is possible that veterinary medicines remain in livestock food products, according to the use of many and various veterinary medicines to protect against disease when livestock animals are breed in limited space. Concentrated and continuous monitoring of residues is needed due to increases in resistance to antibiotics and side effects by eating livestock food products. We developed an analysis method for detecting streptomycin, dihydrostreptomycin, neomycin, gentamicin and spectinomycin in meat using LC/MS/MS and measured sensitivity, precision, accuracy, linearity and recovery according to CODEX guidelines to acquire confidence in the analysis method. Based on the results, we acquired good sensitivity compared to the maximum residue limit (MRL) as limits of detection (LOD) were 0.002-0.016 mg/kg and limits of quantification (LOQ) were 0.006-0.050 mg/kg. The analysis method satisfied the CODEX guidelines. The linearity ($r^2$) values of aminoglycoside antibiotics were 0.9936-0.9980, recoveries were 60-110% and relative standard deviations (RSD) were within 15%. As a result of monitoring for residues in a total 250 samples of livestock foods such as pork, chicken, and beef by the confirmed method, dihydrostreptomycin and gentamicin were detected in 5 pork samples. The residues of these antibiotics were within the MRLs. Thus, the detection ratio was 2% as 5 samples were identified from 250 samples.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.377-382
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• 2018

An HPLC method was developed to quantitate a marker, oxyresveratrol (ORT), for the standardization of mulberry branch extracts (MBE) as a functional ingredient. HPLC was performed on a $C_{18}$ column with a gradient elution using 0.05% $H_3PO_4$ and acetonitrile at a flow rate of 0.8 mL/min, and detected at 320 nm. The HPLC method was validated according to Korea Food and Drug Administration (KFDA) guideline of analytical procedures with respect to specificity, linearity, accuracy and precision. Calibration curve of ORT showed high linearity ($R^2=1$), and limits of detection and quantification were 0.3 and $1.0{\mu}g/mL$, respectively. Relative standard deviation values from intra-and inter-day precision were less than 3.52 and 4.70%, respectively. Recovery rate ranged from 97.64% to 103.69%, and ORT content in MBE was approximately 3.78%. These results suggest that the HPLC method developed for the analysis of ORT in MBE is simple, efficient, and could contribute to the quality control of MBE.