• Mass Spectrometry Letters
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• v.9 no.4
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• pp.100-104
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• 2018

As a part of efforts to establish the positive list system (PLS) in South Korea, a method to determine residual emamectin benzoate (EB) in various aquatic products using QuEChERS-EDTA and LC-MRM was developed. The developed method was validated in the aspects of specificity, linearity (correlation coefficient of at least 0.996), sensitivity (the limit of detection and the lower limit of quantitation ${\leq}5ng/g$), recovery (the recovery range of 87.4 and 96.2), and precision (the relative standard deviation of recovery between 0.9 and 13.5). Additionally, the validated method was successfully applied for monitoring EB contamination in eel, halibut, and shrimp collected from local food markets. To our knowledge, the present method is the first one to determine residual EB in various aquatic products at the level satisfying the PLS and could contribute to the establishment of the PLS in South Korea.

• Journal of Applied Biological Chemistry
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• v.64 no.3
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• pp.285-290
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• 2021

Salicornia herbacea is a type of salt marsh plant that has been used in traditional medicine to treat several diseases. Isorhamnetin-3-O-glucoside (I3G) and quercetin-3-O-glucoside (Q3G) are major flavonoids in S. herbacea that are known to exert various pharmacological activities. Therefore, our study sought to validate and optimize an HPLC/UV-based analytical method for I3G and Q3G yield quantification, as well as to determine its limit of detection, limit of quantification, linearity, precision, and accuracy. Upon testing a concentration range of 31.5-1.9 ㎍/mL the results exhibited good linearity (r² ≥0.9996 and r² ≥0.9999 for I3G and Q3G, respectively), and the procedure was deemed precise (relative standard deviation of ≤3.19 and ≤3.85%, respectively), and accurate (102.6-105.0 and 92.9-95.2%, respectively). The results showed that our proposed method could be used for rapid I3G and Q3G evaluation in S. herbacea.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.976-981
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• 2022

Phenanthrenes are bioactive phenolic compounds found in genus Dioscorea, in which they are distributed more in peel than in flesh. Recent studies on phenanthrenes from Dioscorea sp. peels have revealed the potential for valuable biomaterials. Herein, an analytical method using high-performance liquid chromatography (HPLC) for quantitation of bioactive phenanthrenes was developed and validated. The calibration curves were obtained using the phenanthrenes (1-3) previously isolated from Dioscorea batatas concentrations in the range of 0.625-20.00 ㎍/ml with a satisfactory coefficient of determination (R²) of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) values of the isolated phenanthrenes ranged from 0.78-0.89 and 2.38-2.71 ㎍/ml, respectively. The intraday and interday precision ranged from 0.25-7.58%. The recoveries of the isolated phenanthrenes were from 95 to 100% at concentrations of 1.25, 2.5, and 5.0 ㎍/ml. Additionally, phenanthrenes (1-3) were found in all investigated peel extracts. Hence, the developed method was encouraging for the quantitative analysis of phenanthrenes in genus Dioscorea.

• Food Science of Animal Resources
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• v.43 no.6
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• pp.949-960
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• 2023

This research aimed to validate a high-performance liquid chromatography method for the quantitative determination of bixin and norbixin in various foods. The Diode Array Detector (495 nm) technique was used. Method was validated for specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy, and the measurement uncertainty was assessed. The calibration curve showed excellent linearity (r²≥0.9999) over the tested concentration range of 0.2-25 mg/L. The LOD and LOQ were 0.03-0.11 and 0.02-0.05 mg/L for bixin and norbixin, respectively. The intra-and inter-day accuracies and precisions were 88.0±1.3-97.0±0.5% and 0.2%-2.6% relative SD (RSD) for bixin and 88.2±0.8-105.8±0.8% and 0.3%-2.7% RSD for norbixin, respectively. Inter-laboratory validation for accuracy and precision was conducted in three laboratories, and these results all met the AOAC guidelines. In addition, the relative expanded uncertainty (<22%) satisfied the CODEX recommendation. Furthermore, products distributed in Korea were monitored for annatto extracts using the proposed method to demonstrate its application. The developed analytical method is reliable for quantifying bixin and norbixin in various foods.

• Mass Spectrometry Letters
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• v.2 no.1
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• pp.12-15
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• 2011

The Korean government has regulated emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in waste water of manufacturing facilities producing chlorinated compounds since 2009. As this regulation is expected to be reinforced in 2013 to 50 pg I-TEQ/L, a large sample volume is required for the analysis of trace amounts of PCDD/Fs in waste water. Liquid-liquid extraction (LLE) is used to extract PCDD/Fs from aqueous samples; however, its low efficiency makes it inadequate for analyzing large sample volumes. Herein, we present a disk-type solid-phase extraction (SPE) method for the analysis of dioxin at a part per quadrillion level in waste water. This SPE system contains airtight glass covers with a decompression pump, which enables continuous semi-automated extraction. Small (0.5 L) and large (7 L) samples were extracted using LLE and SPE methods, respectively. The method detection limits (MDLs) were 0.001.0.25 and 0.015.4.1 pg I-TEQ/L for the SPE and LLE methods, respectively. The concentrations of detected congeners with both methods were similar. However, the concentrations of several congeners that were not detected with the LLE method were quantified using the SPE method.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.895-899
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• 2009

A new approach for the determination of acrylamide (AM) in foods by solid phase microextraction-gas chromatography (SPME-GC) was established. AM was bromized and transformed to 2-bromoacrylamide (2-BAM). 2-BAM was then extracted by a commercial SPME fiber, $75-{\mu}m$ Car/PDMS fiber, for GC detection. The influence of extraction and desorption parameters such as extraction temperature and time, stirring rate, desorption temperature, and time were studied and optimized. The mass concentration was proportional to the peak area of 2-BPA from 1.0 to 8,000 ${\mu}g/L$. The detection limit of the SPME-GC for 2-BAM was found to be 0.1 ${\mu}g/L$, and the recoveries and relative standard deviations for different food samples were 74.5 to 102.0%, and 4.2 to 9.1%, respectively. The presented method was applied to the determination of AM in fried foods.

• Journal of Korea Multimedia Society
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• v.25 no.3
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• pp.546-557
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• 2022

Recently, the demand to interpret image data with artificial intelligence in various fields is rapidly increasing. Object recognition and detection techniques using deep learning are mainly used, and video integration analysis to determine unstructured object recognition is a particularly important problem. In the case of natural disasters or social disasters, there is a limit to the object recognition structure alone because it has an unstructured shape. In this paper, we propose intelligent video integration analysis system that can recognize unstructured objects based on video turning point and object detection. We also introduce a method to apply and evaluate object recognition using virtual augmented images from 2D to 3D through GAN.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.198-201
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• 2022

Recently, new cyber threats targeting new technologies are increasing, and hackers' attack targets are becoming broader and more intelligent. To counter these attacks, major security companies are using traditional EDR (Endpoint Detection and Response) solutions. However, the conventional method does not consider the context, so there is a limit to the accuracy and efficiency of responding to an advanced attack. In order to improve this problem, the need for a security solution centered on XDR (Extended Detection and Response) has recently emerged. In this study, we present effective threat detection and countermeasures in a changing environment through XDR trends and development roadmaps using machine learning-based context analysis.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.377-382
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• 2010

This study was conducted to establish a method to analyze biurea decomposed from azodicarbonamide in processed foods such as wheat flour and bread. New method was developed using high performance liquid chromatography mass/mass spectrometry to determine biurea in wheat flour and bakery products. The recovery rate was 94.3-112.5%. The limit of detection for biurea was 0.003 mg/kg, and the limit of quantification was 0.01 mg/kg. The monitoring results for biurea content using established methods showed that biurea was detected at 2.76 mg/kg in the azodicarbonamide-detected flour (detection rate, 2%). The detection rate in processed foods such as baked goods was 27% (16/59). The detection range was 0.19-18.01 mg/kg (average, 3.79 mg/kg). However, it was thought that the detection level was safe due to much lower values than the standard (45 mg/kg). As a result, the newly established biurea analytical method will contribute to the management of azodicarbonamide in processed foods such as wheat flour and bakery products.

• Analytical Science and Technology
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• v.11 no.3
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• pp.161-166
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• 1998

Analytical method of haloperidol (HAL) in serum which has been widely used in therapy of schizophrenic disorders is developed. Gas chromatography/nitrogen-phosphorus detection (GC/NPD) was used for this study. Bromoperidol was used as an internal standard and diethylether as a solvent of three-step extraction. The extraction yield in this procedure was $67.5{\pm}1.9%$ at 15 ng/mL. A good linear response in the range of 1~40 ng/mL was obtained with correlation coefficient of $r^2=0.999$. Detection limit was 0.5 ng/mL when 2 mL of serum was used. This method was applied for the analysis of HAL in serum of schizophrenic patients. After HAL decanoate (HD) was intaken as intramuscular route, HAL levels were determined at second week and forth week. From the result, the concentration of HAL at forth week appeared to 29.6% lower than those at second week. The present method showed low detection limit and high selectivity. Therefore it can be applied for the trace analysis of HAL in serum and the monitoring.