• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.298-302
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• 2009

Samultang is one of traditional medicine composed of Paeonia lactiflora, Angelica gigas, Rehmannia glutinosa and Cnidium officinale. To develop simultaneous determination of paeoniflorin, decursin and 5-HMF in Samultang, a high performance liquid chromatography with diode array detector was used. To separate three marker components, Dionex $C_{18}$ column (5 ${\mu}m$, 120 ${\AA}$, 4.6 mm${\times}$150 mm) was used with a gradient elution system of water and methanol. UV wavelength of detector set at 230 nm and 280 nm. This method was validated by linearity, precision test and recovery test. Calibration curves of three standard components were showed good linear regression ($R^2$>0.9973). LOD and LOQ ranged from 0.08 ${\mu}g$/ml to 0.38 ${\mu}g$/ml and 0.25 ${\mu}g$/ml to 1.16 ${\mu}g$/ml, respectively. The relative standard deviations (RSDs) of data of the inter-day and intra-day experiments were less than 0.54% and 0.89%, respectively. The measured results of recovery test were varied from 93.36 to 107.79 with RSD values 0.01~1.45%. The established method was applied for separation of bio-conversion Samultang sample and compared with control sample.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.3
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• pp.241-250
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• 2017

Recently, there has been growing interest in the emission characteristics and behavior of anthropogenic mercury compounds from emission sources. It is required to establish a standard for reliable mercury measurement method. Therefore, this study has evaluated the applicability of the new measurement method; Continuous Emission Monitoring (US EPA 30A, CEM). In addition, the reliability evaluation was conducted through Ontario Hydro Method (ASTM D6784, OHM) and Sorbent trap method (US EPA Method 30B). As a monitoring result for three months via CEM from cement kiln, the maximum mercury compounds concentration was about $600{\mu}g/Sm^3$. This is because of the various of raw materials and fuel, and the absence of mercury-control device. The mercury compounds concentrations of OHM, Sorbent trap and CEM were 13.64 $(3.33{\sim}32.41){\mu}g/Sm^3$, $13.94(5.97{\sim}23.44){\mu}g/Sm^3$ and $14.68(6.19{\sim}26.75){\mu}g/Sm^3$, respectively. The relative standard deviations (% RSD) of the three methods were 5.1~40.9%. The result of this study suggest that it is possible to apply the CEM in the cement kiln when, QA/QC such as calibration is verified.

• The Korean Journal of Pain
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• v.14 no.1
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• pp.98-103
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• 2001

Neuropathic pain originating from multiple condition of nerve cell injury is common, but is difficult to treat. Even though many drugs such as anti-convulsants, anti-depressants, NSAIDs, opioids have been used, their clinical analgesic action were not satisfactory due to occur severe side effects. Gabapentin was introduced in 1994 as a novel antiepileptic drug and has been used to treat partial seizure. After 1995 gabapentin treatment for reflex sympathetic dystrophy (RSD) started, 45% of the reports about the analgesic efficacy of gabapentin were restricted to the treatments of non-epileptic pain syndrome. This drug is preferred to treat neuropathic pain because of a lower incidence of its side effects than those of other anti-convulsants and anti-depressants. For evaluating it's analgesic efficacy, the changes in the patients' subjective pain intensity was measured by the score on the visual analogue scale (VAS) and patient's objective pain intensity by measuring the skin temperature via infrared thermography were investigated respectively. Side effects of gabapentin were look into. We observed successful relief of neuropathic pain in the three patients which included post-herpetic neuraligia, complex regional pain syndrome (CRPS) and diabetic neuropathic pain, and the side effects of gabapentin were at acceptable levels.

• Analytical Science and Technology
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• v.14 no.1
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• pp.44-49
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• 2001

Solid-phase microextraction (SPME) with $85{\mu}m$ polyacrylate fiber, coupled to gas chromatography-mass spectrometry was used to analyze the plasticizers contained in balloon samples. The balloons were identified to be made of polyisoprene by IR spectroscopy. The plasticizers extracted from the balloon samples soaked in acetone-added water solvent for an hour were quantified by external standard method using nine kinds of plasticizers. The quantification method was validated for standard plasticizers in the range of $0.25-25{\mu}g/g$. The detection limits were $0.11-0.38{\mu}g/g$ for different plasticizers. The RSDs for the reproducibility of this quantitation method were 3.7-14.2%. A few of balloons included risky level of plasticizer concerned as and endocrine disrupter, and it is necessary to regulate these products.

• Analytical Science and Technology
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• v.31 no.3
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• pp.107-111
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• 2018

Currently, ultraviolet-visible spectrophotometry and titration methods are used for assay tests of tramadol hydrochloride injection and raw material in the Korean Pharmacopoeia XI (KP XI). Titration has also been used in the British Pharmacopoeia (BP 2013) for the assay test of tramadol hydrochloride, and the HPLC assay for tramadol hydrochloride raw material has been used in the United States Pharmacopeia (USP 39). In this study, we developed an alternative HPLC assay method for tramadol hydrochloride injection that is up to date and specific, and employs the same method as tramadol hydrochloride capsules. Validation of the HPLC method was conducted to determine linearity, precision, accuracy, system suitability, and robustness. The linearity of the calibration curves in the desired concentration range was good ($r^2$ > 0.9999). RSDs of intra-day precision obtained were 0.05-0.08 % and inter-day precision obtained were 0.08-0.19 %. Accuracy was obtained with recoveries in the range of 98.16 % and 100.90 %. As a result of the system's suitability, the RSD of both retention time and the peak area obtained were 0.07 %. The values of the plate number and tailing factor of tramadol hydrochloride obtained were 7076 and 1.16, respectively. Because of the intermediate precision and robustness of the developed assay, it is expected to become a valuable tool for revising the Korean Pharmacopoeia (KP XI).

• Analytical Science and Technology
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• v.33 no.1
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• pp.23-32
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• 2020

Methamphetamine (MA) is the most common and available drug of abuse in Korea and its primary metabolite is amphetamine (AP). Detection of AP derivatives, such as MA, AP, phentermine (PT), MDA, MDMA, and MDEA by the use of immunoassay screening is not reliable and accurate due to cross-reactivity and insufficient specificity/sensitivity. Therefore, the analytical process accepted by most urine drug-testing programs employs the two-step method with an initial screening test followed by a more specific confirmatory test if the specimen screens positive. In this study, a gas chromatography-mass spectrometric (GC-MS) method was developed and validated for confirmation of MA and AP in human urine. Urine sample (500 µL) was added with N-isopropylbenzylamine as internal standard and ethyl chloroformate as a derivatization reagent, and then extracted with 200 µL of ethyl acetate. Extracted samples were analysed with GC-MS in the SIM/ Scan mode, which were screened by Cobas c311 analyzer (Roche/Hitachi) to evaluate the efficiency as well as the compatibility of the GC-MS method. Qualitative method validation requirements for selectivity, limit of detection (LOD), precision, accuracy, and specificity/sensitivity were examined. These parameters were estimated on the basis of the most intense and characteristic ions in mass spectra of target compounds. Precision and accuracy were less than 5.2 % (RSD) and ±14.0 % (bias), respectively. The LODs were 3 ng/mL for MA and 1.5 ng/mL for AP. At the screening immunoassay had a sensitivity of 100% and a specificity of 95.1 % versus GC-MS for confirmatory testing. The applicability of the method was tested by the analysis of spiked urine and abusers' urine samples.

• Korean Journal of Environmental Agriculture
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• v.29 no.2
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• pp.165-175
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• 2010

A gas chromatographic (GC) method was developed to determine residues of captan, folpet, captafol, and chlorothalonil, known as broad-spectrum protective fungicides for the official purpose. All the fungicide residues were extracted with acetone containing 3% phosphoric acid from representative samples of five agricultural products which comprised rice, soybean, apple, pepper, and cabbage. The extract was diluted with saline, and dichloromethane partition was followed to recover the fungicides from the aqueous phase. Florisil column chromatography was additionally employed for final cleanup of the extracts. The analytes were then determined by gas chromatography using a DB-1 capillary column with electron capture detection. Reproducibility in quantitation was largely enhanced by minimization of adsorption or thermal degradation of analytes during GLC analysis. Mean recoveries generated from each crop sample fortified at two levels in triplicate ranged from 89.0~113.7%. Relative standard deviations (RSD) were all less than 10%, irrespective sample types and fortification levels. As no interference was found in any samples, limit of quantitation (LOQ) was estimated to be 0.008 mg/kg for the analytes except showing higher sensitivity of 0.002 mg/kg for chlorothalonil. GC/Mass spectrometric method using selected-ion monitoring technique was also provided to confirm the suspected residues. The proposed method was reproducible and sensitive enough to determine the residues of captan, folpet, captafol, and chlorothalonil in agricultural commodities for routine analysis.

• Journal of Biomedical Engineering Research
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• v.38 no.4
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• pp.183-189
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• 2017

Electrosurgical Unit(ESU) is medical equipment that cut or coag tissues using electrical energy. It is used in hospitals' outpatient clinic room and operating room. Improper use of an ESU may cause fatal injuries to the patient, such as burns. So, before using an ESU, make sure that it is supplying enough energy for cut and coag by measuring the output power and checking the output power cable. In this study, we developed a simple ESU power measurement system PW100 that allows anyone to check the basic output power. And PW100 can check the state of the cable associated with the output power before using ESU. Then, we compared the measured output power of the PW100 with an ESU Analyzer which was commercialized, and compared the performance. In the experiment, the output power measured by the PW100 was lower value than an ESU Analyzer's that. However, the PW100's output power measured in the 5% error range and showed stable reproducibility by a low %RSD value.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.745-756
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• 2013

The purpose of this study is to evaluate representativeness of fuel-based emission factors. Twelve light-duty diesel vehicles which meet Euro-3 to 5 legislative emission limits were selected for emission tests. Second-by-second modal emission rates of vehicles were measured on a standard laboratory chassis dynamometer system. An off-cycle driving cycle was developed as a representative Korean real-world on-road driving cycle. Fuel-based emission factors were developed for short trip segments that involved in the selected driving cycle. Each segment was defined to have unit travel distance, which is 1 km, and characterized by its average speed and Relative Positive Acceleration (RPA). Fuel-based $NO_x$ emission factors demonstrate relatively good representativeness in terms of vehicle operation conditions. $NO_x$ emission factors are estimated to be within ${\pm}20%$ of area-wide emission factor under more than 40% of total driving situations. This result implies that the fuel-based $NO_x$ emission factor could be practically implemented into the on-road emission management strategies, such as a remote sensing device (RSD). High emitting vehicles as well as high emitting operating conditions heavily affect on the mean values and distributions of CO and THC emission factors. Few high emitting conditions are pulling up the mean value and biasing the distributions, which weaken representativeness of fuel-based CO and THC emission factors.

• Journal of Pharmaceutical Investigation
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• v.35 no.5
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• pp.375-381
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• 2005

A rapid and specific high-performance liquid chromatographic method was developed and validated for the simultaneous determination of prostaglandin $E_{1}\;(PGE_{1})$ and prostaglandin $E_{1}$ ethyl ester $(PGE_{1}-EE)$ in hairless mouse skin homogenate. The sample treatment procedure involved deproteination and precipitation by acetonitrile. $PGE_{1}$ and $PGE_{1}-EE$ in supernatant were separated in a reversed-phase C18 column without being interfered by other components present in hairless mouse skin homogenate. 9-Anthracenecarboxylic acid was used as an internal standard. The retention times of $PGE_{1}$, 9-anthracenecarboxylic acid and $PGE_{1}-EE$ were, 4.5, 9.5 and 18.0 min, respectively. The assay showed linearity from 1 to $40\;{\mu}g/ml$ for both $PGE_{1}$ and $PGE_{1}-EE$. Precision expressed as RSD ranged from 2.3 to 14.1 % for $PGE_{1}$ and 1.6 to 11.0% for $PGE_{1}-EE$. Accuracy ranged from 100.5 to 119.6 % for $PGE_{1}$ and from 98.0 to 103.7% for $PGE_{1}-EE$. This method was employed successfully to follow the time course of concentrations of $PGE_{1}$ and $PGE_{1}-EE$ in hairless mouse skin homogenate for stability study.