• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.203-210
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• 2023

Ferimzone Z is a fungicide for effectively controlling rice blast. Under light irradiation conditions, it undergoes a rapid conversion to its E-stereoisomer. Given the importance of isomers in risk assessments of residues in crops, an analytical method was developed for individual isomer quantification. A comparative analysis performed using two columns in HPLC-MS/MS demonstrated that the isomers were successfully separated using the Cadenza column. For the brown rice sample preparation, 5 g of the homogenized sample was saturated with 7 mL of water. The sample was then extracted with a 10 mL mixed solvent of acetonitrile and ethyl acetate (1:1, v/v) that contained 0.1% formic acid, and it was subsequently partitioned with magnesium sulfate and sodium chloride. The upper layer was purified using dSPE containing C₁₈ and PSA sorbents. The established method was subjected to method validation, and it showed recovery rates of 90.6-98.8% (RSD ≤ 3.9%) at concentrations of 0.01, 0.1, 2 mg/kg, with a soft matrix effect (%ME) ranging from -3.1% to +6.5%. This method can be employed in monitoring studies of brown rice to determine the conversion ratio from the Z isomers to the E isomers.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.25-30
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• 2010

This paper describes a simultaneous method for the determination of two aminoglycosides (neomycin and gentamicin) using solid phase extraction followed by liquid chromatograph-mass spectrometry. The extract was applied to an WCX and HLB solid phase extraction cartridge. The cartridges were washed with water and methanol, and analytes were eluted with TCA buffer-acetonitrile mixture. The aminoglycosides were separated by ion-pairing reversed phase mode prior to ESI-LC/MS. Under the conditions applied neomycin was almost separated from all the gentamicin compounds. No interfering peaks from endogenous compounds of matrix were noted at the elution position of the analytes. Recoveries of neomycin fortified at levels of 0.25, 0.5, 1.0 and 2.0 mg/kg seafood samples ranged from 92 to 115%. Recoveries of gentamycin fortified at levels of 0.05, 0.1, 0.2, 0.4 mg/kg seafood samples ranged from 99 to 116%. Method detection limits in four seafood sample matrices were between 0.002 and 0.033 mg/kg.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.310-320
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• 2009

In this paper, we estimate area-averaged solution of peening residual stress using a 3-D multi-impact symmetry-cell FE model. The symmetry-cell model includes factors reflecting peening phenomena and plastic shot. Area-averaged solution is much closer to XRD experimental solution than 4-node-averaged solution in plastic shot FE model. We then obtain FE Almen saturation curve corresponding to experimental Almen curve based on area-averaged solution. Using the curve, we obtain FE area-averaged solution in major peening materials, and compare the FE solution with experimental solution. In peening materials, surface, maximum compressive residual stress and deformation depth reach experimental solutions. Thus, FE Almen curve is useful for estimation of residual stress solution and could improve the efficiency of peening process. Consequently, it is confirmed that concept of area-averaged solution is the realistic analytical method for evaluation of peening residual stress.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.768-777
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• 2013

The purpose of this study is to be conducive to work improvement through analyzing turnover intention and organizational commitment of EMT within medical institution. The subjects of this study were randomly extracted 188 EMT. The survey period was conducted from May 3, 2011 to May 19 (May 3rd-4th in G Province, May 14th in B Metropolitan City, May 18th-19th in D Metropolitan City). An analytical method was made with SPSS WIN program(Version 12.0). As a result of research, the turnover intention was high in women(p<.001), in under 30 years old(about 4.9 times, p<.001), in the unmarried(about 4.3 times, p<.001), and in junior college graduate(about 4 times, p<.001). Also, the turnover intention was high in income with under 1,500,000 won(about 3.3 times, p<.001), in working career with under 5 years(about 3.2 times, p<.001), in feeling the legal work limit(about 1.8 times, p<.05), and in group with low job satisfaction(p<.001). In correlation between organizational commitment and job variable, the variables in age, marriage, academic background, turnover intention, income, career, and legal work limit except gender and job satisfaction showed positive correlation with organizational commitment(p<.01). As for the factors affected on the organizational commitment, the turnover intention(p<.01), the legal work limit(p<.01), and the job satisfaction(p<.001) had significant effect on organizational commitment.

• Analytical Science and Technology
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• v.7 no.3
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• pp.339-347
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• 1994

A multicolumn system consisted of two valve(10-port and 6-port valve)-three column (28% DC 200, SP 1700 and Chromosorb 102 column) was developed. Nine natural gas components composed of $N_2$, $CH_4$, $CO_2$, $C_2H_6$, $C_3H_8$, $i-C_4H_{10}$, $n-C_4H_{10}$, $i-C_5H_{12}$ 및 $n-C_5H_{12}$ completed all the baseline separation within 18 minutes. The accuracy and the precision of this system was tested. The retention times and the peak areas were determined with a repeatability between 0.02 and 0.16%, and less than 1%, respectively. Calibration curves for natural-gas components were plotted by the partial pressure injection method of pure gases, and good linear relationships for each component were presented. By using these calibration curves the accuracy of the multicolumn system compaired with that of the single column system for a certified standard gas of natural gas. As a result, relative error in the single and the multicolumn system was less than 0.5% and 0.04%, respectively. The result of application of this system in the analysis of importing LNG composition showed that the heating values calculated by the multicolum system were estimated lower compared with those calculated by the single column system and consequently, the importing price of LNG was able to be cut down.

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.197-205
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• 2002

Volatile organic compounds (VOCs) are an important public health problem throughout the world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. Personal exposure measurements are needed to evaluate the relationship between microenvironmental concentrations and actual exposures. It is also important to investigate exposure frequency, duration, and intensity, as well as personal exposure characteristics. In addition to air monitoring, biological monitoring may contribute significantly to risk assessment by allowing estimation of absorbed doses, rather than just the external exposure concentrations, which are evaluated by environmental and personal monitoring. This study was conducted to establish the analytic procedure of VOCs in air, blood, urine and exhaled breath and to evaluate the relationships among these environmental media. The subjects of this study were selected because they are occupationally exposed to high levels of VOCs. Environmental, personal, blood, urine and exhalation samples were collected. Purge ＆ trap, thermal desorber, gas chromatography and mass selective detector were used to analyze the collected samples. Analytical procedures were validated with the“break through test”, 'quot;recovery test for storage and transportation”,“method detection limit test”and“inter-laboratory QA/QC study”. Assessment of halogenated compounds indicted that they were significantly correlated to each other (p value < 0.01). In a similar manner, aromatic compounds were also correlated, except in urine sample. Linear regression was used to evaluate the relationships between personal exposures and environmental concentrations. These relationships for aromatic and halogenated are as follows: Halogen $s_{personal}$ = 3.875+0.068Halogen $s_{environmet}$, ($R^2$= .930) Aromatic $s_{personal}$ = 34217.757-31.266Aromatic $s_{environmet}$, ($R^2$= .821) Multiple regression was used to evaluate the relationship between exposures and various exposure deter-minants including, gender, duration of employment, and smoking history. The results of the regression model-ins for halogens in blood and aromatics in urine are as follows: Halogen $s_{blood}$ = 8.181+0.246Halogen $s_{personal}$+3.975Gender ($R^2$= .925), Aromatic $s_{urine}$ = 249.565+0.135Aromatic $s_{personal}$ -5.651 D.S ($R^2$ = .735), In conclusion, we have established analytic procedures for VOC measurement in biological and environmental samples and have presented data demonstrating relationships between VOCs levels in biological media and environmental samples. Abbreviation GC/MS, Gas Chromatography/Mass Spectrometer; VOCs, Volatile Organic Compounds; OVM, Organic Vapor Monitor; TO, Toxic Organicsapor Monitor; TO, Toxic Organics.

• Applied Biological Chemistry
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• v.20 no.2
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• pp.236-241
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• 1977

Analytical method of carbofuran (2,3-dihydro-2, 2-dimethyl-7-benzofuranyl methyl carbamate) residues and its persistence in rice seeds, rice seedlings, rice plants and soils were studied by gas-liquid chromatographic analysis using electron capture detector. 1. The effective column material for clean-up is Florisil (5% $H_2O$)+Alumina (4% $H_2O$)+absorbent mixture with rinsing the first 300l of eluants to remove impurities in the column materials. 2. The method of applying an gelatin encapsulated carbofuran to the root zone of rice plant is the longest persistence in its residues. 3. By seed treatment, no carbofuran residues were detected in rice seeds and seedlings. 4. The amounts of carbofuran residues in rice seedlings is in proportion to the soaking time of rice seedlings in carbofuran solution rather than the concentration of the chemical. 5. Applying carbofuran by root zone has the higher and the loger residual effect than broadcast. 6. Persistence of carbofuran in the high clay content soil is longer than in the low clay content soil. 7. No carbofuran residue was detected in rough rice at havesting time.

• Journal of Food Hygiene and Safety
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• v.25 no.3
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• pp.226-231
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• 2010

We aimed at the monitoring medroxyprogesterone acetate (MPA) residue amount in meats and confirmed the safety of its residue in meats. Optimized condition for analytical and instrumental methods was obtained by method validation. The limit of detection (LOD) and limit of quantification (LOQ) were validated at 1.5 and 5.0 ug/kg, respectively. The calibration curve showed good linearity ($r^2$ = 0.9968) within the concentration range of 5.0~50.0 ug/kg. We selected progesterone-d9 for internal standard, The recoveries in fortified meat ranged from 67.5 to 109.56% at the 3 spiking levels. As the regulation of MPA analysis method used by LC-MS/MS on other products have established. We selected 3 species of farm stock products (cattle, pig, chicken) and purchased at the markets of seven major cities. The total 196 of meat including 46 of domestic beef, 43 of import beef, 60 of domestic pork, 12 of import pork and 35 of domestic chicken. No residue of synthetic growth hormones were detected in cattle, pig and chicken samples tested.

• Analytical Science and Technology
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• v.25 no.3
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• pp.178-189
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• 2012

As phthalates classified as toxic to reproduction category 2 and endocrine disrupting chemicals were more strictly regulated as Substances of Very High Concern (SVHC) for authorization in under EU REACH and considered as priority substances in RoHS II, standardization of phthalate testing method is now being proposed in IEC 62321 of IEC TC 111 and the 2nd revision of KS M 1991 is also finished. In order to assist standardization activities related to phthalating testing, solvent extraction part of existing national standards were compared and verified. Recovery of DEHP (diethylhexyl phthalate) from PVC (polyvinyl chloride) by Soxhlet extraction increased in the order of methanol, toluene, dichloromethane and hexane from 46.9% to 95.3% as measured by GC-MS. Optimum extraction time was verified to be 6 hours using hexane. Recovery of DBP (dibutyl phthalate), BBP (butylbenzyl phthalate), and DEHP from different matrixes such as PVC, nitro cellulose, ABS (acrylonitrile butadiene styrene). and EPDM(ethylene propylene diene monomer) rubber were evaluated to be more than 90% up to 99%. The detection limits of phthalates in solvent extraction followed by GC-MS analysis were 0.08~0.3 ${\mu}g/mL$ in solution and 8~30 mg/Kg in polymeric samples. GC-MS analyses of phthalates were carried out using different solvent extraction based on the EN 14372, ASTM D 7083, Japanese test method (MHLW 0906-4) and KS M 1991, proving that equivalent recoveries ranging from 98%~99% were obtained. DBP and DEHP were detected in three consumer products such as a child toy, a power cable and manicure with the amount of 22~1,910 mg/kg.

• Steel and Composite Structures
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• v.33 no.3
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• pp.445-461
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• 2019

The ultrasonic guided wave-based technique has become one of the most promising methods in non-destructive evaluation and structural health monitoring, because of its advantages of large area inspection, evaluating inaccessible areas on the structure and high sensitivity to small damage. To further advance the development of damage detection technologies using ultrasonic guided waves for the inspection of welded components in structures, the transmission characteristics of the ultrasonic guided waves propagating through welded joints with various types of defects or damage in steel plates are studied and presented in this paper. A three-dimensional (3D) finite element (FE) model considering the different material properties of the mild steel, high strength steel and austenitic stainless steel plates and their corresponding welded joints as well as the interaction condition of the steel plate and welded joint, is developed. The FE model is validated against analytical solutions and experimental results reported in the literature and is demonstrated to be capable of providing a reliable prediction on the features of ultrasonic guided wave propagating through steel plates with welded joints and interacting with defects. Mode conversion and scattering analysis of guided waves transmitted through the different types of weld defects in steel plates are performed by using the validated FE model. Parametric studies are undertaken to elucidate the effects of several basic parameters for various types of weld defects on the transmission performance of guided waves. The findings of this research can provide a better understanding of the transmission behaviour of ultrasonic guided waves propagating through welded joints with defects. The method could be used for improving the performance of guided wave damage detection methods.