• Analytical Science and Technology
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• v.29 no.2
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• pp.94-103
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• 2016

An analytical method was developed to determine the amount of spinetoram (spinetoram J and spinetoram L) in livestock samples. The spinetoram was extracted with acetonitrile and purified through a primary secondary amine (PSA) sorbent. The spinetoram residues were then quantified and confirmed using a liquid chromatography–tandem mass spectrometer (LC-MS/MS) in the positive ion mode using multiple reactions monitoring (MRM). Matrix-matched calibration curves were linear over the calibration ranges (0.005-0.5 mg/kg) into a blank extract with r² > 0.994. The limits of detection and quantification were 0.002 and 0.01 mg/kg, respectively. The recovery results of spinetram ranged between 81.9-106.4% at different concentration levels (LOQ, 10LOQ, 50LOQ, n=5) with relative standard deviations (RSDs) less than 10%. All values were consistent with the criteria ranges requested in the Codex guidelines (CAC/GL40, 2003). An interlaboratory study was conducted to validate the method. The proposed analytical method proved to be accurate, effective, and sensitive for spinetoram determination. The method will be used as an official analytical method in Korea.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.287-292
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• 2002

To establish effective and safe control method against Phytophthora root rot caused by Phytophthora capsici on tomato in hydroponic culture, three pesticides, oxadixyl copper hydroxide 8% WP, metalaxyl copper oxychloride 15% WP, and dimethomorph. dithianon 38% WP at 4 concentration levels were tested on potato dextrose agar medium inoculated with Phytophthora capsici. All pesticides inhibited mycelial growth, but two pesticides of them, metalaxyl copper oxychloride WP and dimethomorph. dithianon WP, were selected as effective pesticides for the efficacy test in a hydroponic culture. Forty days after transplanting of tomato seedlings, 4 ml of sporangia of P. capsici (about 25 sporangi/ml) per plot was inoculated around tomato plant root, and then 5 days after inoculation, the pesticides diluted at 5,000 times were drenched 1, 2 or 3 times per plot on the culture cube at 15 days interval. Fifteen days after drenching, tomato fruits and hydroponic culture solution were sampled for the analysis of pesticide residues. Dimethomorph was detected 0.001 and 0.003 mg/kg in tomato of the plots sprayed 2 and 3 times with dimethomorph dithianon WP of which detection levels were far below compared with 1.0 mg/kg of the Korean MRL of dimethomorph on tomato. Incidences of Phytophthora root rot were $30.5{\sim}50%$ in the plots drenched at 1 or 2 times with metalaxyl.copper oxychloride WP, and $16.7{\sim}25%$ in the plots treated with dimethomorph dithianon WP. However, there was no incidence of Phytophthora root rot in the plots treated at 3 times with both of pesticides, showing no phytotoxic effect. Based on the results, the drenching of these pesticides on the culture cube could be recommended as a very safe and effective control method for Phytophthora root rot in tomato.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.639-648
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• 2010

The optimal conditions for the analysis of BPA by HPLC-MS/MS was investigated and the ultrasound degradation capacity of the BPA, with the goal to establish the proper directions for analyzing infinitesimal quantities of BPA by HPLC-MS/MS was examined. The MDL and LOQ of BPA analyzed by HPLC-MS/MS were measured 0.13 nM and 1.3 nM respectively, its sensitivity about 620 and 32 times greater than HPLC-UV (MDL: 81.1 nM, LOQ: 811 nM) and FLD (MDL: 4.6 nM, LOQ: 46 nM). In other words, the new method enables the analysis of BPA with the accuracy up to one 1,180th of the amount specified in U.S. EPA guideline for drinking water. Degradation rate of BPA by ultrasound measured over 95% under 580 kHz and 1000 kHz frequency within 30 minutes of treatment, whereas the rate showed some decrease at 28 kHz frequency. At 580 kHz of ultrasound has proven to be the most effective among others at degradation rate and $k_1$ value, so we concluded that this frequency of ultrasound creates hospitable condition for the combined process of degradation by pyrolysis and oxidization. With the addition of 0.01 mM of $CCl_4$, BPA with the initial concentration of 1 ${\mu}M$ was degraded by more than 98% within 30 minutes, the $k_1$ value measured 5 minutes and 30 minutes into the experiment both showed increases by 1.4 and 1.1 times, respectively, compared with BPA without $CCl_4$. It is also found that the main degradation mechanism of BPA by ultrasound is oxidization process by OH radical, based on the fact that the addition of 10 mM of t-BuOH decreased the rate of BPA degradation by around 60%. However, 33% of BPA degradation rate obtained with the addition of t-BuOH implies further degradation done by pyrolysis or other sorts of radical beside OH radical.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.240-245
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• 2012

Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium that causes serious infection, particularly in immunocompromised patients. Also, P. aeruginosa possessing carbapenem-resistant metallo-${\beta}$-lactamases (MBL) has been reported with increasing frequency in Korea. We therefore analyzed the level of multidrug-resistant clinical P. aeruginosa isolated from a secondary hospital in Korea in 2010. A total of 92 isolates of P. aeruginosa were collected from Sahmyook Medical Center in 2010. Susceptibility to antimicrobial agents was determined by analysis of the minimum inhibitory concentration test; the inhibitor-potentiated disk diffusion (IPD) test was performed for MBL detection. RAPD-PCR was used for genotyping to rapidly characterize P. aeruginosa strains isolated from clinical patients. The percentages of non-susceptible isolates were as follows: 40.2% to ceftazidime, 58.7% to meropenem, 56.5% to gentamicin, 46.7% to tobramycin, 62.0% to ciprofloxacin and 97.8% to chloramphenicol. The 29 multidrug-resistant strains were screened by the IPD test: of the 21 PCR-positive isolates, 19 were IPM-1 producers and 2 were VIM-2 producers. Among the 19 IMP-1-producing P. aeruginosa isolates, 16 isolates showed similar patterns, and three different banding patterns were observed. The proportion of IMP-1-producing multidrug-resistant P. aeruginosa from clinical isolates steadily increased in this secondary hospital in Korea in 2010. This study provides information about the antimicrobial-resistant patterns and genotype of multidrug-resistant P. aeruginosa isolated from clinical isolates in Korea, 2010.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.690-697
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• 2006

This study has been carried out to estimate mean concentration and the daily intake of 2 artificial sweeteners (aspartame and sucralose) by analyzing food samples. Total number of samples was 755 and the number of samples detected for sweeteners was 33 (detection rate was 4.4%). Contribution rate to total estimated daily intake (%) of artificial sweeteners in food categories was high in candy for aspartame and sucralose. Total Estimated Daily Intakes $({\Sigma}EDI)$ for different age groups were high in $13{\sim}19$ years old for aspartame and $7{\sim}12$ years old for sucralose. Total estimated daily intakes $({\Sigma}EDI)$ of men and women were 5.10 mg/person/day and 4.88 mg/person/day, respectively. Total estimated daily intakes $({\Sigma}EDI)$ of artificial sweeteners were shown as follows; 3.75 mg/person/day for aspartame and 1.27 mg/person/day for sucralose, respectively and assuming a body weight of 55 kg. These values were ranged from $0.15{\sim}0.17%$ of acceptable daily intake (ADI) evaluated by FAO/WHO and $1.0{\sim}21.4%$ of theoretical maximum daily intake (TMDI), and therefore, judged to be safe.

• Analytical Science and Technology
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• v.9 no.4
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• pp.336-344
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• 1996

The extraction of trace cobalt, copper, nickel, cadmium, lead and zinc in urine samples of organic and alkali metal matrix into chloroform by the complex with a dithizone was studied for graphite furnace AAS determination. Various experimental conditions such as the pretreatment of urine, the pH of sample solution, and dithizone concentration in a solvent were optimized for the effective extraction, and some essential conditions were also studied for the back-extraction and digestion as well. All organic materials in 100 mL urine were destructed by the digestion with conc. $HNO_3$ 30 mL and 30% $H_2O_2$ 50 mL. Here, $H_2O_2$ was added dropwise with each 5.0 mL, serially. Analytes were extracted into 15.0 mL chloroform of 0.1% dithizone from the digested urine at pH 8.0 by shaking for 90 minutes. The pH was adjusted with a commercial buffer solution. Among analytes, cadmium, lead and zinc were back-extracted to 10.00 mL of 0.2 M $HNO_3$ from the solvent for the determination, and after the organic solvent was evaporated, others were dissolved with $HNO_3-H_2O_2$ and diluted to 10.00 mL with a deionized water. Synthetic digested urines were used to obtain optimum conditions and to plot calibration-eurves. Average recoveries of 77 to 109% for each element were obtained in sample solutions in which given amounts of analytes were added, and detection limits were Cd 0.09, Pb 0.59, Zn 0.18, Co 0.24, Cu 1.3 and Ni 1.7 ng/mL, respectively. It was concluded that this method could be applied for the determination of heavy elements in urine samples without any interferences of organic materials and major alkaline elements.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.315-321
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• 2012

Fate of acetamiprid and imidacloprid aerially sprayed to control pine wood nematode (Bursaphelenchus xylophilus) were studied in a forest of Haman area. Acetamiprid 20% SL or imidacloprid 20% DC were diluted 100 times and applied two times as rate of 50 L/ha using an aircraft of Bell 206 L helicopter. Average acetamiprid deposits on forest floor ranged from 2 to 4% of standard aerial application rate. Following to the second application, acetamiprid deposits in the pine needle ranged 1.8~8.5 mg/kg and then gradually decreased to 1.2~2.1 mg/kg after 48 days. Deposits on the plant washed off by rainfall and reached to soil surface was ca. 17% of the application rate. All of acetamiprid on the ground resided in the forest floor covering the soil surface, where acetamiprid residues were decreased to a quarter at 48 days after the second application, but they were not detected in soil beneath it. And the only low level of acetamiprid residues, 0.0003 mg/L, was detected in the reservoir nearby the experimental forest on the day of aerial application. The acetamiprid detection was presumably due to spray drift. And average imidacloprid deposits on forest floor ranged from 1 to 3% of standard aerial application rate. Following to the second application, imidacloprid deposits in the pine needle analysed very low concentration of 0.1 mg/kg, but the amount of imidacloprid in wash-off in standard and two-fold treatment were ca. 8% and 4% of the application rate, respectively. Most of imidacloprid on the ground also resided in the forest floor, where imidacloprid residues were decreased to a twentieth at 111 days after the second application, and they were detected below 0.5% of the application rate in sol beneath it. And the low level of imidacloprid, 0.0003~0.0017 mg/L, were detected in the streams in the experimental forest. It was not to the level of contamination concerns.

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.303-309
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• 2005

This study was conducted to examine the effects of OA on metaphase of meiosis II and the mitochondrial activity of cytoplasm in bovine cumulus oocytes complexes(COCs) during in vitro maturation. Hanwoo COCs were collected from the slaughterhouse cow ovaries and matured in TCM199 supplemented with $0.1\%$ PVA, 0.2 uM, 2 uM, 20 uM OA for the maturation rate of OA concentration. For the maturation effects between OA and cycloheximide(CX), COCs were matured in TCM199 with 25 ug/mL CX, 25 ug/mL CX (6 hrs culture) plus 2 uM OA or 2 uM OA only at a atmosphere $5\%\;CO_2,\;95\%$ air $39^{\circ}C$ for 6, 12, 24 hrs. To evaluate the nuclear types of matured COCs, cumulus cells were removedby $0.5\%$ hyaluronidase sol. and oocytes were fixed in 1:3 acetic acid ethyl alcohol for 30 sec. and then stained with $0.1\%$ basic Fuchsin sol. For the detection of fluoriscent intensity (FI) of matures oocytes, cumulus cells were removed same as performed above and were stained with 20 nM mite tracker for 20 min. at $39^{\circ}C$. Mitochondrial activity of FI in matured oocytes was imaged by laser conforcal microscopy (Fluoview, Olympus, Japan) and were measured scanned face on 5 um from median to endpoint of oocytes. Statical analysis of nuclear types observed the three replicates was carried out with ANOVA and Fisher's protected least significant difference test using the STATVIEW program. FI of matures oocytes was compared the multiples of the least intensity among the measured oocytes. Maturing in TCM199 supplemented with $0.1\%$ PVA, 0.2 uM, 2 uM, 20 uM OA, metaphase B were showed 72.0, 50.0, 70.0, $68.8\%$, respectively and there were different significant(p<0.05). In the case of treatment with OA and CX, metaphase were $73.8\%,\;8.2\%,\;45.5\%,\;73.7\%$ in $0.1\%$ PVA-TCM199, 25 ug/mL CX, 25 ug/mL CX plus OA or 2uM OA only, respeclively. FI was revealed the increasing tendency during the process of maturation. Whereas FI in CX was decreased about 3 times compared to the other treatments of 6 hrs maturation. We conclude that OA regulates bovine COCs maturation and induces the mitochondrial activity during the process of maturation.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.119-128
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• 2017

BACKGROUND: Miscellaneous cereal have been largely consumed in Korea as due to their physiological functions beneficial to human health. The cereals are currently a social concern because they have been found to contain heavy metals. Thus, monitoring heavy metals in the cereals is an important requirement for food safety analysis. In this study, we determined arsenic concentration in the cereals randomly harvested from different markets. METHODS AND RESULTS: Inorganic arsenic was determined by ICP-MS coupled with HPLC system. The HPLC-ICP-MS analysis was optimized based on the limit of detection and recover test to reach $0.13-1.24{\mu}g/kg$ and 94.3-102.1%, respectively. The concentrations of inorganic arsenic equivalent to daily exposure were levels of $19.91{\mu}g/day$ in mixed grain, $1.07{\mu}g/day$ in glutinous rice, $0.77{\mu}g/day$ in black brown rice, $0.13{\mu}g/day$ in barley and $0.11{\mu}g/day$ in soybeans. CONCLUSION: The levels of arsenic in miscellaneous cereals were found lower than the recommended The Joint FAO/WHO Expert Committee on Food Additives (JECFA) levels, suggesting that the cereals marketed in Korea are not potential concern in risk assessment.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.8-13
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• 2010

Bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) were obtained by a polymerization reaction of epichlorohydrin (ECH) with bisphenol A (BPA) or bisphenol F (BPF). These compounds are commonly used as monomers or additives such as a polymerization stabilizer and a hydrochloric acid scavenger of epoxy resin, polyvinyl chloride (PVC)-containing organosols and polyester lacquers, that are applied to the internal surface of most canned foods to impart chemical resistance. The unreacted BADGE, BFDGE and their reaction products migrating from epoxy resin, PVC-containing organosol and/or polyester lacquer-based food packaging materials into the foods have recently become an issue of great concern because of increased customer demand for safety. This study was conducted to develop a rapid and sensitive simultaneous analysis method based on HPLC/FLD and HPLC/APCI-mass and to evaluate the concentration of BADGE, BFDGE and their metabolites, BADGE $H_2O$, BADGE $2H_2O$, BADGE HCl, BADGE 2HCl, BADGE HCl $H_2O$, BFDGE $H_2O$, BFDGE $2H_2O$, BFDGE HCl, BFDGE 2HCl and BFDGE HCl $H_2O$ for 133 canned food samples. The method provided a linearity of 0.9997-0.9999, a limit of detection of $0.01-0.13\;{\mu}g/mL$, a limit of quantitation of $0.03-0.44\;{\mu}g/mL$ and a recovery (%) of 85.64-118.18. The number of samples containing BADGE, BFDGE or their metabolites were: 28/133 (21.1%), with levels of 0.400-0.888 mg/kg being observed for aqueous foods (19/133) and 0.093-0.506 mg/kg being observed for oily foods (9/133).