• Natural Product Sciences
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• v.17 no.4
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• pp.328-336
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• 2011

A high-performance liquid chromatography (HPLC) with diode array detector (DAD) method was established for the discrimination of a folk medicine Forsythia suspensa and Forsythia viridissima. Five and three representative metabolites of the lignan and phenolic glycoside classes were selected for the analysis from F. suspensa and F. viridissima, respectively. The optimal chromatographic conditions were obtained on an ODS column (5 ${\mu}m$, $4.6{\times}250$ mm) with the column temperature at $40^{\circ}C$. The mobile phase was composed of methanol and 0.3% acetic acid using an isocratic elution with the flow rate 1 mL/min. Detection wavelength was set at 280 nm. All calibration curves showed good linear regression ($r^2$ > 0.996) within test ranges. Limits of detection (LOD) and limits of quantitation (LOQ) values were lower than 0.096 and 0.291 ${\mu}g/mL$, respectively. The developed method provided satisfactory precision and accuracy with overall intra-day and inter-day variations of 0.07-0.63% and 0.14-0.62%, respectively, and the overall recoveries of 97.79-102.46% for all of the compounds analyzed. In addition, effectiveness of diverse extraction methods was compared to each other for the development of standard analytical method. The verified method was successfully applied to the quantitative determination of representative metabolites in fifty-three commercial F. suspensa samples and fifteen commercial F. viridissima samples from diverse sources. The overall analytical results showed the unequivocal differences in bioactive constituents between F. suspensa and F. viridissima.

• Analytical Science and Technology
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• v.17 no.4
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• pp.302-307
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• 2004

Determination of actinides in the environmental sample requires separation of each element. This procedure is tedious and time consuming. And also, the detection limits of some nuclides using alpha spectrometry are rather higher. To overcome the lower detection limit and complicated separation procedure, a simple analytical technique for the determination of actinide isotopes in the environmental samples was developed and applied to IAEA and NIST reference sediment samples. For the separation of actinides from matrix, anion exchange resin and TRU-spec extraction chromatography resin were used and chemical yields were obtained using natural uranium, thorium, $^{242}Pu$ and $^{243}Am$ tracers. For overcoming the higher detection limits of U and Th in alpha spectrometry, neutron activation analysis was applied. Using combined method, the detection limit was increased about 10 times. The activity values of each isotope were consistent with the reference values reported by IAEA and NIST.

• Analytical Science and Technology
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• v.14 no.2
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• pp.115-122
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• 2001

Butyltin compounds, including mono-(MBT), di-(DBT) and tributyltin(TBT) were analyzed in 44 human blood samples randomly collected from a hospital in "K" a city. Gas chromatograph equipped with flame photometric detector(FPD) was used to quantify the amounts of butylin compounds. Method detection limits(MDL) of this analytical method were 3.69ng Sn/g for MBT, 0.91ng Sn/g for DBT and 1.09ng Sn/g wet wt for TBT respectively. Standard reference material(SRM) containing of $1.3{\mu}g/g$ TBT as chloride was analyzed to check if this analytical results would be reliable. Recovery of about 90% was obtained through this analysis, indicating that the analytical method from butyltin compounds blood was reliable. The concentrations of butyltin compounds ranged MDL(<3.69) to 7.93ng Sn/g for MBT and 1.15 to 5.41ng Sn/g wet wt for DBT. Tributyltin was below detection limit in all samples. Detection limits of our results are lower than those reported by Kannan et al. who reported butyltin compounds in 33 human blood samples in the United States. Detection of MBT and DBT on blood sample implies that butyltin compounds could be absorbed through consumption of seafoods or exposure to food stuffs made of plastics and household items. Further study is needed to examine if butyltin compounds in blood can be reliably analyzed and used as intake index.

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1165-1171
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• 1999

The analysis of trace herbicides using the on-line SPE-HPLC system and a photochemical reaction was studied. 18 compounds of herbicides including eight triazines, six phenoxy acids and esters, and four other herbicides were examined. The on-line SPE-HPLC system developed for selection of eluting solvent improved chromatographic efficiency. The recoveries of herbicides were higher than 77%. With 100 mL tap water samples, the detection limits for all analytes were in the 0.1-2.3×10-10 M range. Detection was done by a UV or fluorescence spectrometer after photochemical reaction at the end of the column with 2W or 450W mercury lamp. Without a photochemical reaction, all compounds responded to 230 nm UV detector, but phenoxy acids and esters were weakly detected. However, with a photochemical reaction, these compounds were selectively detected at 320 nm wavelength of UV absorption and 400 nm emission of the fluorescence detectors. This method can be used for the analysis of environmental water containing herbicides at trace levels.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.3
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• pp.215-220
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• 2020

This paper deal with estimating the direction of arrival (DOA) of GNSS signal using two antennae for spoofing detection. A technique for estimating the azimuth angle of a received signal by applying the interferometer method to the GPS carrier signal is proposed. The experiment assumes two antennas placed on the earth's surface and estimates the azimuth angle when only GPS signal are received without spoofing signal. The proposed method confirmed the availability through GPS satellite placement simulation and experiments using a dual antenna GPS receiver. In this case of using dual antenna, an azimuth angle ambiguity of the received signal occurs with respect to the baseline between two antennas. For this reason, the accurate azimuth angle estimation is limits, but it can be used for deception by cross-validating the ambiguity.

• Korean Journal of Clinical Pharmacy
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• v.5 no.2
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• pp.71-74
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• 1995

A high performance liquid chromatographic method has been developed for the simultaneous analysis of non-steroidal anti-inflammatory drugs in plasma. The simultaneous determination of ibuprofen, fenoprofen and ketoprofen is performed by RP-HPLC with UV detection. The chromatographic system consisted of Spherisorb octyl column$(5{\mu}m)$ ; the mobile phase was $acetonitrile\;-\;0.5\%$ phosphoric acid(55 : 45, v/v) and the detection wavelength was 230nm. Tolmetin was employed as an internal standard. The method described is rapid and simple with sensitivity limits of $2.0{\mu}g/ml$ ibuprofen, $0.5{\mu}g/ml$ fenoprofen and $0.3{\mu}g/ml$ ketoprofen and is suitable for routine clinical and pharmacokinetic studies.

• Analytical Science and Technology
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• v.12 no.4
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• pp.341-345
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• 1999

The separation and determination of inorganic cations by a capillary zone electrophoresis was studied. Cations were separated by the capillary column and detected by indirect UV method. The running buffer of 0.03 M creatinine and 0.02 M-hydroxy isobutylic acid solution (pH 4.8) was used to improve the mobility of ions in the column. A potential of 18 kV was applied at anode. A complete separation of cations ranged within 15 min and detection limits were between 0.1 and 1.0 ppm. The applicability of the method for real samples was demonstrated.

• Journal of the Korean Chemical Society
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• v.38 no.6
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• pp.418-426
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• 1994

This study was aimed at the detection of 40 semi-volatile organic base/neutral compounds from soil among 129 priority pollutants listed by EPA. Two extraction procedures, sonication extraction and Soxhlet extraction, were studied as a extraction and concentration method for priority pollutants in soil. Extracts were analyted by GC/MS-SIM(selected ion monitoring). The analytical methods were tested by standard compounds spiked into blank soil. Accuracy and precision of the methods were measured by calculation of mean recovery and mean relative standard deviation. And the method detection limits were estimated.

• Journal of Ginseng Research
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• v.19 no.2
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• pp.134-137
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• 1995

Ginseng saponins were analyzed by thermospray (TSP) LCMS method using ODS column and with acetonitrile/ammonium acetate solution. Optimal condition for TSP Lchfs was found as follows: capillary temperature: 33$0^{\circ}C$ repelled voltage: 200 V, and concentration of ammonium acetate: 0. 05 M. Panaxadiol and panaxatriol type saponins showed characteristic fragment ions. The calibration curve of ginseng saponin showed good linearity with a correlation coefficient of 0.99. Detection limits using selected ion monitoring (SIM) technique were improved by 10~200 times compared to conventional HPLCnnr detection method.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1118-1123
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• 2009

Event-specific real-time polymerase chain reaction (PCR) detection method for genetically modified (GM) maize MIR604 was developed based on integration junction sequences between the host plant genome and the integrated transgene. In this study, 2 primer pairs and probes were designed for specific amplification of 100 and 111 bp DNA fragments from the zSSIIb gene (the maize endogenous reference gene) and MIR604. The quantitative method was validated using 3 certified reference materials (CRMs) with levels of 0.1, 1, and 10% MIR604. The method was also assayed with 14 different plants and other GM maize. No amplification signal was observed in real-time PCR assays with any of the species tested other than MIR604 maize. As a result, the bias from the true value and the relative deviation for MIR604 was within the range from 0 to 9%. Precision, expressed as relative standard deviation (RSD), varied from 2.7 to 10% for MIR604. Limits of detections (LODs) of qualitative and quantitative methods were all 0.1%. These results indicated that the event-specific quantitative PCR detection system for MIR604 is accurate and useful.