• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.278-283
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• 2005

Cement and paraffin waste form were prepared with a acid extraction method for the analysis of radionuclides generated from nuclear power plants. The acid extraction method was carried out with $HNO_3-HCl$ acid. At first, we compared the method with the microwave acid digestion method using SRM. The solutions of decomposed SRM were then analyzed by AAS and ICP-AES. The acid extraction method had shown good results as microwave acid digestion method. This method provided recovery values greater than $80\%$ for metallic elements.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1199-1202
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• 2006

A simple, sensitive and rapid spectrofluorimetric method was developed for determination of mefenamic acid in pharmaceutical preparation and human urine. The procedure is based on the oxidation of mefenamic acid with cerium (IV) to produce cerium (III), and its fluorescence was monitored at 354 nm after excitation at 255 nm. The variables affecting oxidation of drug were studied and optimized. Under the experimental conditions used, the calibration graphs were linear over the range 0.03-1.5 mg $L^{-1}$. The limit of detection was 0.009 mg $L^{-1}$ and the relative standard deviation for 5 replicate determinations of mefenamic acid at 1.0 mg $L^{-1}$ concentration level was 1.72%. Good recoveries in the range of 102-107 and 102-109% were obtained for pharmaceutical preparation and human urine, respectively. The proposed method was applied to the determination of MF in one pharmaceutical preparation and human urine. The amounts of mefenamic acid found are very similar to those obtained by a standard method.

• YAKHAK HOEJI
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• v.29 no.3
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• pp.117-123
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• 1985

A clorimetric determination method of pyruvic acid using hydroxylamine was studied. Hydroxylamine was reacted with pyruvic acid to form complex compound in the presence of Cu(II) ion. Optimal conditions for the quantitative analysis were investigated and the structure of complex was examined spectrometrically. The molar ratio (2:1) and the stability constant ($1.88{\times}10^{4}$) of the complex were measured. It was the characteristic feature of this method that the commonly encountered interfering substances such as fructose, glucose and lactic acid do not infuence the measurement of pyruvic acid.

• YAKHAK HOEJI
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• v.4 no.1
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• pp.47-49
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• 1959

Another application of the new quantitative analytical method of prussic acid by "Microdiffusion analysis" for the determination of prussic acid in human blood was studied. The blood containing potassium cyanide was dropped in outer room of unit, and then N-sulfuric acid was added. The liberated HCN gas was absorbed into nickel sulfate solution of inner room, afterward, absorbed prussic acid was determined with EDTA by residual titration. The result was coincided with the result of Liebig Denigs' method at ordinary temperature.

• Journal of the Korea Convergence Society
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• v.7 no.5
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• pp.169-173
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• 2016

Anodic oxidation of aluminum has a sulfuric acid method and a oxalic acid method. Sulfuric acid concentration of the sulfuric acid method is 15~20 wt%. In the case of soft anodizing used in the $20{\sim}30^{\circ}C$ range, and voltage is the most used within a DC voltage 13~15V. In the case of hard anodizing used in the $0{\sim}-5^{\circ}C$ range. An aluminum oxide layer is made using sulfuric acid and oxalic acid. In this study, thermal fatigue of aluminum oxide layer which is made using sulfuric acid and oxalic acid is compared. Crack generating temperature of a sulfuric acid method and a oxalic acid method is $500^{\circ}C$ and $600^{\circ}C$. Thermal fatigue of aluminum oxide layer which is made using oxalic acid is better than thermal fatigue of aluminum oxide layer which is made using sulfuric acid. The characteristic of thermal fatigue can be explained by using thermal expansion coefficient of Al and Al2O3 and manufacturing temperature on Al anodizing. It was made possible through the convergent study to propose the manufacturing method of the anodic oxidation product used at a high temperature.

• Journal of Acupuncture Research
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• v.28 no.2
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• pp.89-95
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• 2011

Objectives : The purpose of this study was to investigate the composition of Rehmannia glutinosa's essential oils with Rehmanniae Radix herbal acupuncture Methods : I obtained the essential oils of Rehmannia Radix by hydrodistillation extraction method and supercritical fluid extraction(SFE) method, and then I analyzed those by GC/MS(gas chromatography/mass spectrum). Results : 1. With GC(gas chromatography) and GC/MS(gas chromatography/mass spectrum) analysis. I identified 9 compounds in the Rehmanniae Radix's essential oil obtained through the SFE method. The main compounds were as follows : Hexachloroethane(2.24%), N-Butyl-benzenesulfonamide(2.05%), hexadecanoic acid(1.93%), hexadecanoic acid, ethyl ester(3.49%), 9,12-Octadecadienoic acid(z,z)(2.70%), (9E)-9-Octadecenoic acid(6.14%), ethyl linoleate(4.43%), ethyl oleate(5.80%). 2. I failed to get Rehmanniae Radix's essential oil obtained through the hydrodistillation method. 3. With GC(gas chromatography) and GC/MS(gas chromatography/mass spectrum) analysis. I identified 4 compounds in the Rehmanniae Radix's essential oil obtained through the hydrodistillation method. The main compounds were as follows : Ethylbis(trimethylsilyl)amine(1.04%), 2-(Trimethylsiloxy)benzoic methyl ester(2.65%), Hexadecanoic acid trimethylsilyl ester(12.61%), octadecanoic acid, trimethylsilyl ester(6.28%). Conclusions : The substances by hydrodistillation method may not perfectly match with the substances by supercritical fluid extraction(SFE) method in essential oils extracted form Rehmanniae Radix. But, the main substances was assumed Hexadecanoic acid and octadecanoic acid.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.6
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• pp.379-384
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• 2005

A high-performance liquid chromatography assay method for oxolinic acid in fish products was developed, evaluated and validated through the monitoring of oxolinic acid based on farming and distribution. The recovery rate of the developed method was $102.3-106.7\%$ as compared to conventional methods. The stock solution was stable for 3 weeks under refrigerated condition at $4^{\circ}C$ The performance limit was evaluated as 0.01ppm of oxolinic acid in fish muscle. 478 fish samples such as olive flounder, genuine porgy, common sea bass and black rock fish collected from fish farms in the coastal area from September 2001 to October 2004 were analyzed to evaluate overall efficiency of the modified method and to monitor the actual condition of oxolinic acid usage in fish farm. According to the monitoring results, the modified method was suitable for analysis of oxolinic acid in fish muscle and oxolinic acid might be used in a small portion of fish farms. The suggested analysis method of oxolinic acid was registered in the Korean Official Methods of Food Analysis and is being utilized for fishery products by the Korea Food and Drug Adminstration and the National Fisheries Products Quality Inspection Service.

• The Korean Journal of Food And Nutrition
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• v.32 no.4
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• pp.379-384
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• 2019

This study was to investigate the sorbic acid, benzoic acid and sulfur dioxide in commonly consumed beverages, snacks and instant ramens in Korea. A total of 150 food samples including 50 beverages, 50 snacks and 50 instant ramens were examined using the Korea Food Code method. Sorbic and benzoic acid were analyzed by the HPLC method, whereas sulfur dioxide was measured by Monnier-Williams method. Our results indicated that benzoic acid was detected in six beverages samples, and its concentration was in the range of 3.08-11.94 mg/kg. The contents of both sorbic and benzoic acid in 50 beverage samples did not exceed the residue allowance standards set by the Ministry of Food and Drug Safety (MFDS). Sulfur dioxide was detected in 12 beverages samples, but its content was lower than the detection limit specified in the method by the Korea Food Code. On the other hand, sorbic acid was not detected all samples. These results provide a basic data regarding sorbic acid, benzoic acid and sulfur dioxide in commonly consumed beverages, snacks and instant ramens in Korea.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.519-524
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• 1998

Formaldehyde is known to have adverse health effects, and is also found to be a product of atmospheric. photochemical reaction%. Several methods have been employed for the measurement of formaldehyde. Among them, two common methods are comparatively evaluated in this study, i.e. the chromotropic acid method and the HPLC method coupled with 2,4- dinitrophenylhydrazine (DNPH) derivatization of carbonyl compounds. Method evaluation and validation were performed with respect to repeatability, linearity, collection efficiency, and recovery efficiency. Comparison of formaldehyde concentrations measured simultaneously in the field using the two (n=20) and 35.8%, respectively. Overall, the measured levels by chromotropic acid method appeared to ice significantly higher than those by DNPH-HPLC method, indicating a positive interference due to the other aldehydes collected together with formaldehyde.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.41-46
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• 2001

This study was conducted to develop a high throughput system for screening acetolactate synthase(ALS) inhibitors, and to detect basic mother molecules for developing new novel herbicide candidates. The high throughput screening (HTS) method using 96-well plate and microplate reader was developed. This method is 8 times more effective than basic technique in one cycle per person. Futhermore, considering for less than 1/10 volume of materials required for ALS test and enzyme kinetics with 16 times faster speed compared to those of former procedure, this HTS method has more than 100 times higher efficacy than basic system in a consecutive procedure. We discovered 11 new ALS inhibitors such as 2-oxoglutaric acid, aminooxyacetic acid, azelaic acid, citric acid, cyanuric fluoride, itaconic acid, malonic acid, niclosamide, oxalic acid, glyoxylic acid, and suramin from 107 commercial plant-specific inhibitors using this technique. We hope these results might be useful to discover lead compounds for developing new novel herbicide candidate.