• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.332-338
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• 2012

A simple and sensitive analytical method was developed using gas chromatography with electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS) for determination of Picoxystrobin in agricultural products (apple, hulled rice, mushroom, pepper, soybean, and mandarin). Picoxystrobin residues were extracted with acetonitrile, partitioned with saline water, and then they were cleaned up on a florisil solid-phase extraction (SPE) cartridge to obtain an extract suitable for analysis by GC-ECD and GC-MS. The method was validated using 6 agricultural product samples spiked with Picoxystrobin at different concentration levels (0.02, 0.05 and 0.5 mg/L). Average recoveries of Picoxystrobin (using each concentration three replicates) ranged 64.0~98.3% with relative standard deviations less than 10%, calibration solutions concentration in the range 0.1~5 mg/L, and limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.02 mg/L, respectively. The result showed that the developed analytical method is suitable for Picoxystrobin determination in agricultural products.

• Journal of Food Hygiene and Safety
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• v.29 no.4
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• pp.285-291
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• 2014

Saflufenacil is a low-volatile and uracil-based herbicide. This herbicide is used for pre-and post-emergence control of major broadleaf weeds. The objective of present study was to develop and validate an analytical method for saflufenacil determination in agricultural products for ensuring the food safety. The saflufenacil residues in samples were extracted with acetone, dichloromethane, and then purified with silica and graphitized carbon cartridge. The purified samples were analyzed by HPLC-UVD and confirmed with LC-MS. The linear range of saflufenacil was $0.1{\sim}5.0{\mu}gmL^{-1}$ with the correlation coefficient (r) = 0.999. Average recoveries of saflufenacil ranged from 80.5% to 110.2% at the spiked level of $0.02{\sim}0.5mgkg^{-1}$, while the relative standard deviation was 0.3~7.3%. In addition, the limit of detection and limit of quantification were 0.005 and $0.02mgL^{-1}$, respectively. Furthermore, an interlaboratory study among three labs was conducted to validate the method, and the results were satisfactory.

• Journal of Food Hygiene and Safety
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• v.34 no.5
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• pp.431-437
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• 2019

This study was conducted to develop a simultaneous analysis method for ferulic acid, caffeic acid, catechin and taxifolin from Health Functional Food (HFF) Pinus Pinaster bark extract. The simultaneous analytical method for ferulic acid, caffeic acid, catechin and taxifolin is carried out using UPLC-MS/MS. The method validation was performed to determine selectivity, linearity, accuracy, limit of detection (LOD), limit of quantification (LOQ) and precision for ferulic acid, caffeic acid, catechin and taxifolin. LC-MS/MS method was established using an Acquity UPLC BEH $C_{18}$ Column and was applied for these 4 compounds. Product-ion traces, at m/z $194.2{\rightarrow}133$, $180.2{\rightarrow}135$, $290.3{\rightarrow}245$, $304.3{\rightarrow}248$, were used for quantitative analysis of ferulic acid, caffeic acid, catechin and taxifolin, respectively. Excellent linearity ($r^2=0.999$) was observed for ferulic acid, caffeic acid, catechin and taxifolin in the concentration range (50-2500 mg/L). The observed recoveries of these 4 compounds were found to be between 84.9 and 104.9%, while precision was between 1.20 and 4.43% relative standard deviation (% RSD).

• Korean Journal of Food Science and Technology
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• v.51 no.5
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• pp.420-424
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• 2019

An HPLC analysis method was developed and standardized for the detection of dieckol as a functional food ingredient in Ecklonia cava extracts. HPLC was performed using a Capcell Pak C18 column ($250{\times}4.6mm$, $5{\mu}m$) with a gradient elution of water and acetonitrile, both containing 0.1% (v/v) trifluoroacetic acid, at a flow rate of 1.0 mL/min at $25^{\circ}C$. The eluate was detected at 230 nm. For validation, the specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ) of dieckol were measured. The calibration curve for the detection of dieckol had high linearity ($R^2=0.9994$), with LOD and LOQ values of 0.38 and $1.16{\mu}g/mL$, respectively. Recovery of the quantified compound ranged from 99.61 to 100.71%. The relative standard deviation values of the intra-day and inter-day precisions were less than 1.7 and 1.25%, respectively. These results indicate that the reported HPLC method is simple, reliable, and reproducible for the detection of dieckol in Ecklonia cava extracts.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.52-57
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• 2019

Method development and validation of decursin for the standardization of Angelica gigas Nakai as a functional ingredient and health food were accomplished. The quantitative determination method of decursin as a marker compound of aerial parts of Angelica gigas Nakai extract (AAGE) was optimized by HPLC analysis using a C18 column ($3{\times}150mm$, $3{\mu}m$) with 0.1% TFA in water and acetonitrile as the mobile phase at a flow rate of 0.5 mL/min and detection wavelength of 330 nm. The HPLC/PDA method was applied successfully to quantification of the marker compound in AAGE after validation of the method with linearity, accuracy, and precision. The method showed high linearity in the calibration curve at a coefficient of correlation ($R^2$) of 0.9994 and the limit of detection and limit of quantitation were $0.011{\mu}g/mL$ and $0.033{\mu}g/mL$, respectively. Relative standard deviation (RSD) values of data from intra- and inter-day precision were less than 1.10% and 1.13%, respectively. Recovery of decursin at 0.5, 1, 5 and $10{\mu}g/mL$ were 92.38 ~ 104.11%. These results suggest that the developed HPLC method is very useful for the determination of marker compound in AAGE to develop a health functional material.

• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.259-265
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• 2021

A diagnostic test for viral hemorrhagic septicemia virus (VHSV), which infects more than 80 species of freshwater and marine fish at home and abroad, causing mass mortality, was conducted to provide quantitative data on the amount of virus expression in various tissues of flounder in chronological order. The tissues were collected in chronological order after the intraperitoneal injection of 3.0E+07 tissue culture infective dose₅₀ (TCID₅₀) per 0.1mL per fish of VHSV to randomly selected flounder. As a result of relative quantification through real-time PCR, the highest levels of virus expression were found in the spleen, kidney, gill, and liver on day 5. This study proved that the spleen was an appropriate site for the final diagnosis of VHSV in the early stages of infection and will provide important information for the diagnosis of legal infectious diseases in Korea.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.34-41
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• 2021

The purpose of this research is to improve analysis methods of determining the contents of fatty acids in infant formulas and follow-up formulas. A gas chromatography (GC) method was performed on a GC system coupled to flame ionization detector, with a fused silica capillary column (SP2560, 100 m×0.25 mm, 0.20 ㎛). The method was validated using standard reference material (SRM, NIST 1849a). Performance parameters for method validation such as specificity, linearity, limits of detection (LOD) and quantification (LOQ), accuracy and precision were examined. The linearity of standard solution with correlation coefficient was higher than 0.999 in the range of 0.1-5 mg/mL. The LOD and LOQ were 0.01-0.06 mg/mL and 0.03-0.2 mg/mL, respectively. The recovery using standard reference material was confirmed and the precision was found to be between 0.8% and 2.9% relative standard deviation (RSD). Optimized methods were applied in sample analysis to verify the reliability. All the tested products had acceptable contents of fatty acids compared with component specification for nutrition labeling. The result of this research will provide efficient experimental information and strengthen the management of nutrients in infant formula and follow-up formula.

• Analytical Science and Technology
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• v.34 no.6
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• pp.241-250
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• 2021

Calibration curves are essential in quantitative methods and for improving the accuracy of analyte measurements in biological samples. In this study, a statistical analysis model built in the R language (The R Foundation for Statistical Computing) was used to identify a set of weighting factors and regression models based on a stepwise selection criteria. An LC-MS/MS method was used to detect the presence of urinary methamphetamine, amphetamine, and 11-nor-9-carboxy-Δ⁹ -tetrahydrocannabinol in a sample set. Weighting factors for the calibration curves were derived by calculating the heteroscedasticity of the measurements, where the presence of heteroscedasticity was determined via variance tests. The optimal regression model and weighting factor were chosen according to the sum of the absolute percentage relative error. Subsequently, the order of the regression model was calculated using a partial variance test. The proposed statistical analysis tool facilitated selection of the optimal calibration model and detection of methamphetamine, amphetamine, and 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol in urine. Thus, this study for the selection of weighting and the use of a complex regression equation may provide insights for linear and quadratic regressions in analytical and bioanalytical measurements.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.431-445
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• 2022

A quantitative phase analysis method of X-ray powder diffraction was studied to determine the mineral content of clay-rich rocks practically as well as effectively. For quantitative X-ray powder diffraction analysis of the clay-rich rocks, it is necessary to prepare whole-rock powder samples with a random orientation by side mounting method. In addition, for the identification of the clay minerals in the rock, it is required to prepare an oriented mount specimen with a clay particle size of 2 ㎛ or less, ethylene glycol treatment, and heat treatment. RIR (reference intensity ratio) and Rietveld method were used for the quantitative analysis of the clay-rich rocks. It was possible to obtain the total clay and the non-clay minerals contents from the whole-rock X-ray diffraction profiles using the RIR values. In addition, it was possible to calculate the relative content of each clay mineral from the oriented X-ray diffraction profiles of the clay particle size and assign it to the total clay. In the Rietveld method of whole-rock X-ray diffraction, effective quantitative values were obtained from the Rietveld diffraction patterns excluded the region of less than 10 degrees (2θ). Similar quantitative values were shown in not only the RIR but the Rietveld methods. Therefore, the analysis results indicate a possibility of a routine quantitative analysis of clay-rich rocks in the laboratory. However, quantitative analysis of clay minerals is still a challenge because there are numerous varieties of clay minerals with different chemical and structural characteristics.

• Analytical Science and Technology
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• v.36 no.3
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• pp.105-112
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• 2023

Lycopene, a carotenoid hydrocarbon is known to have effects on reducing cardiovascular risk factors, blood lipids, and blood pressure. Thus, a lot of supplementary foods with lycopene in several dosage forms like soft capsule filled with liquid and hard capsule filled with powder are available in a market. Recently, however, our research group found that the lycopene assay in Supplementary Food Code of South Korea is only valid for oily lycopene preparation. Thus, here, we developed a simple method to determine lycopene in solid preparations for Supplementary Food Code of South Korea using saponification and liquid chromatography with an absorbance detector. The method was validated following Ministry of Food and Drug Safety guidelines. All validation parameters observed in this study were within acceptable criteria of the guidelines (selectivity, linearity of r² ≥ 0.991, lower limit of quantification of 0.0149 mg/mL, accuracy as recovery (R) between 92.70 and 97.18 %, repeatability as relative standard deviation (RSD) values of R between 0.85 and 1.59 %, and reproducibility as the RSD value of interlaboratory R of 3.70 %). Additionally, the practical sample applicability of the validated method was confirmed by accuracy between 98.81 and 101.59 % observed from its lycopene certified reference material (CRM) analyses. Therefore, the present method could contribute to fortify the supplementary food safety management system in South Korea.