• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.125-133
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• 2011

The purpose of this study was to develop a methodology to detect spinosad which are difficult to analyze by multi-component simultaneous analysis of pesticide residues. We monitored spinosad due to the paucity of related information. The spinosad was determined using HPLC with UV detector at 250 nm. Correlation coefficient ($r^2$) for standard curve of spinosad A and D at standard concentration of 0.1-5.0 mg/kg were 0.999, respectively. Limit of quantitation (LOQ) of HPLC analysis was 0.005 mg/kg while limit of detection (LOD) was 0.001 mg/kg. Recovery experiments were conducted on five representative agricultural products to validate the analytical method. The recovery of proposed methods ranged from 74.9% to 104.0% and relative standard deviations were less than 10%. Spinosad residues were investigated in 16 commodities collected from 22 provinces. In this study, residues on all samples were not detected.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.78-84
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• 2006

A high performance liquid chromatography assay method for spiramycin in fish muscle was developed. The developed method was evaluated and validated by monitoring spiramycin in olive flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli) and in live conger eel (Anguilla japonica) in fish farms and distribution centers. Using the developed method, the recovery rate was up to 82.4-88.8%, which was higher than that of conventional methods (77.6-87.1%). In particular, the proposed sample treatment protocol was suitable for use with fish samples to remove low molecular weight materials and pigments that could interfere an accurate analysis. The prepared stock solution was very stable, and it remained chemically stable for 5 weeks at $4^{\circ}C$. The performance limit of the developed method for spiramycin acid in fish muscle was 0.05 ppm. One hundred thirty-four fish samples including olive flounder, black rock fish and live conger eel were analyzed to evaluate the overall efficiency of the modified method and to monitor the actual condition of spiramycin usage in fish farms. Olive flounder and black rock fish were collected from fish farms in coastal areas of Korea, and live conger eels were purchased from a fish market in the Busan area from September 2001 to March 2002. According to the overall performance of the developed method, it was considered suitable for the monitoring of spiramycin in fish muscle. The suggested method of analysis for spiramycin in fish muscle is registered in the Korean Official Methods of Food Analysis and is currently tieing utilized for fishery products inspection by the Korea Food and Drug Administration and the National Fisheries Products Quality Inspection Service.

• Korean Journal of Food Science and Technology
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• v.42 no.2
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• pp.130-135
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• 2010

Picrate, enzyme-picrate and instrumental analysis methods using IC (Ion Chromatography) and HPLC (High Performance Liquid Chromatography) were compared for their effectiveness in determining cyanide in extracts of Maesil, which is classified as a harmful substance. First, the picrate method showed the shortest analysis time (about 5 hr). The color of picrate paper changed at 0.01 mg/$200\;mL\;CN^-$. However, it was difficult to detect cyanide from amygdalin of glucosides. Second, we performed a qualitative analysis for total cyanide (free cyanide and cyanide from amygdalin) by the enzyme-picrate method using $\beta$-glucosidase and a quantitative analysis by spectrophotometry. Finally, analysis of cyanide by IC and HPLC required the longest determining time (about 17 hr) as well as pretreatment for each free cyanide and amygdalin. These results suggest that enzyme-picrate is the most effective analysis method for the detection of cyanide in Maesil extracts.

• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.203-213
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• 2005

Oxytetracycline, tetracycline, chlortetracycline and doxycycline in honey were separated by solid phase extraction (SPE) and determined with high performance liquid chromatography (HPLC) with UV/Visible detector. Analysis was carried out using following conditions: XTerra $C_8$ column $(3.9\times150mm\;i.d. 5{\mu}m)$, mobile phase composed of 0.01M oxalic acid : methanol : acetonitrile (820 : 80 : 100, v/v/v), isocratic pump at a flow rate of 0.9 ml/min. and $50{\mu}l$ of injection volume, UV/Visible detector with wavelength of 360nm. The calibration curves of four tetracyclines showed linearity $(\gamma^2>0.999)$ at concentration range of $100\~1,000 ng/ml$. The recoveries in fortified honey represented more than $70\%$ with low coefficient of variation $(<10\%)$ for concentration range of four tetracyclines. The detection limits for oxytetracycline, tetracycline, chlortetracycline and doxycycline were 13.8, 14.6, 26.2 and 24.9ng/g in acacia honey. respectively. We also monitored tetracyclines residue in domestic honey [n : 38, acacia (20), wild flower (18) ] and foreign honey [n=22, legally distributed (13), illegally distributed (9)] using modified Charm II screening and HPLC confirmation methods. Seven of the 60 samples $(11.7\%)$ were suspect positive using modified Charm II screening test. Chlortetracycline residue was found in one foreign honey (illegally distributed) tested at concentrations of 0.22 ppm. Conclusively, for more effective control of tetracyclines used in beekeeping should be further survey for residues in honey and also national guidelines (maximum residue limit : MRL) and methods should be obligatory.

• Analytical Science and Technology
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• v.7 no.1
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• pp.33-39
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• 1994

The purpose on this study was to develop a new improved chromatographic method for determination of trace phenols from environmental waste water. The research was carried out with selected 8 phenols, and solid-phase extraction was employed as sample pretreatment method. The coupling of XAD-4 and Dowex $1{\times}8$ resin as preconcentration column increased the selectivities toward interferences coexisted in matrix. Automation was accomplished with on-line process of pretreatment and HPLC system. After elution of sample through XAD-4 column, phenols were adsorbed by dispersion force, then displaced from it by ACN basified, simultaneously and selectively readsorbed via anion exchange on Dowex $1{\times}8$. Dowex $1{\times}8$ column was washed by water. Phenols readsorbed were removed from Dowex $1{\times}8$ column by a minimum volumn of methanol containing HCl. Each pretreatment step was connected by switching valves and the eluate was directly on-line injected to obtain fast and reliable results into the HPLC. Recovery of phenols was greater than 90%. To examine utility of this method, analysis of phenols from laboratory waste water sample which was added some organic pollutants to find with phenols on environmental waste water were also accomplished without their interference effects.

• The Korea Journal of Herbology
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• v.25 no.4
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• pp.77-84
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• 2010

Objectives : Taraxaci Herba et Radix (THR) is widely used as a food and medicinal herb in Korea. It has been used for treatment of virus inflammatory disease, liver diseases and gastritis. So far, anti-inflammatory effects and constituents of various species in THR has not been studied for comparison. The aim of this study is to compare the anti-inflammatory effects of the aerial part and root from various THR. Also, we have compared the contents of its known constituents with each. Methods : In this study, we estimated anti-inflammatory effect and compared their constituent by HPLC. For the determination of anti-inflammatory effects, we investigated NO and $PGE_2$ production by ELISA. The expressions of iNOS was determined by western blotting in LPS-induced RAW 264.7 macrophage cells. And, standard compounds which are methyl gallate, gallic acid, syringic acid and esculetin of THR were analyzed by HPLC using a $C_{18}$ column. Results : Methanol extracts of THR decreased NO and $PGE_2$ production. The expressions of iNOS protein were also decreased in methanol extracts of THR. As a result, HPLC analysis showed that they showed similar patterns. Methyl gallate and esculetin showed the highest content. Methyl gallate was included over 10% content in each aerial part and root of THR. Conclusions : These results indicate that most of THR distributed in Korea might represent therapeutic agent for treatment of inflammatory diseases.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.81-86
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• 2015

A simple analytical method to quantify formaldehyde in water at lower levels (${\mu}g/L$) was developed using a high performance liquid chromatography (HPLC) and acetylacetone as a derivative reagent. Unlike conventional methods, no extraction and/or concentration were required. The derivative reagent was added into samples and reacted for 30 minutes at $80^{\circ}C$ prior to the analysis of formaldehyde using HPLC. The method detection limit and the limit of quantification for this method were 1.6 and $5.0{\mu}g/L$, respectively. This method also achieved high precision (0.6-3.0%) and accuracy (91.6-106.3%). The recovery rates for various environmental samples ranged from 92.0 to 115.2%.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.1
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• pp.1-16
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• 1991

In this study, sampling and analytical procedures were evaluated for the determination of ambient levels of atmospheric PAH, both in gaseous and particulate phase. The method involves low-volume sampling and Soxhlet extraction of the filters and Tenax absorbent, followed by a clean-up stage using a silica column prior to analysis by reversed-phase HPLC with wavelength programmable fluorescence and UV detection. A total of 18 PAH were identified and quantified, all of which have been of environmental concern. In order to validate the methodology and to ensure compatibility of the results, the analytical method used for the determination of PAH was evaluated with respect to the efficiencies of extraction and clean-up procedure, HPLC separation, and lower limits of detection. In addition, substrate dependency of PAH recovery was investigated for the two types of fiters, i.e. glass fiber and PTFE filters.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.27-37
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• 2019

Background: The structural conversions in ginsenosides induced by steaming or heating or acidic condition could improve red ginseng bioactivities significantly. In this paper, the chemical transformations of red American ginseng from fresh Panax quinquefolium L. under steaming were investigated, and the possible mechanisms were discussed. Methods: A method with reversed-phase high-performance liquid chromatography coupled with linear ion trap mass spectrometry ($HPLC-MS^n$)-equipped electrospray ionization ion source was developed for structural analysis and quantitation of ginsenosides in dried and red American ginseng. Results: In total, 59 ginsenosides of protopanaxadiol, protopanaxatriol, oleanane, and ocotillol types were identified in American ginseng before and after steaming process by matching the molecular weight and/or comparing $MS^n$ fragmentation with that of standards and/or known published compounds, and some of them were determined to be disappeared or newly generated under different steaming time and temperature. The specific fragments of each aglycone-type ginsenosides were determined as well as aglycone hydrated and dehydrated ones. The mechanisms were deduced as hydrolysis, hydration, dehydration, and isomerization of neutral and acidic ginsenosides. Furthermore, the relative peak areas of detected compounds were calculated based on peak areas ratio. Conclusion: The multicomponent assessment of American ginseng was conducted by $HPLC-MS^n$. The result is expected to provide possibility for holistic evaluation of the processing procedures of red American ginseng and a scientific basis for the usage of American ginseng in prescription.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.120-143
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• 2018

The analytical methods and their ambient levels of organic nitrogenous compounds such as nitrosamines, nitramines (nitroamines), imines, amides and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) in the atmosphere are summarized and discussed. Sampling for the analysis of organic nitrogenous compounds was mostly conducted using high volume air sampler. The direct liquid extraction (DLE) using sonification and the pressurized liquid extraction (PLE) using the accelerated solvent extraction (ASE) have been frequently employed for the extraction of organic nitrogenous compounds in the atmospheric samples. After extraction, clean-up via filtration and the solid phase extraction (SPE) and concentrations using nitrogen and rotary evaporator have been generally conducted but in some studies the clean-up and concentration steps have been omitted to prevent the loss of analyte and improve the recovery rate of the analytical procedure. Instrumental analysis was mainly carried out using gas chromatography (GC) or the high performance liquid chromatography (HPLC) coupled with the single quadrupole mass spectrometer or tandem mass spectrometer in the electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) mode and analysis sensitivity of nitrosamines and nitramines were higher in NCI mode. Desirable sampling and analysis methods for analyzing particulate organic nitrogenous compounds are suggested.