• 한국환경농학회지
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• 제34권2호
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• pp.120-127
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• 2015

본 연구에서는 엇갈이배추 재배기간 중 살균제 amisulbrom을 살포하고, 농약 살포 후 0(2시간 이내), 1, 3, 5, 7 및 10일에 엇갈이배추 시료를 채취하여 amisulbrom을 분석하고 amisulbrom의 생물학적 반감기를 산출하여 생산단계 농약 잔류허용기준(PHRL; Pre-Harvest Residue Limit)을 설정하였다. 엇갈이배추에 잔류한 amisulbrom은 acetonitrile과 dichloromethane으로 각각 추출 및 분배를 진행하여 HPLC-UVD로 분석하였다. Amisulbrom의 분석정량한계는 0.04 mg/kg이었으며, 평균 회수율은 0.4 및 2.0 mg/kg의 두 수준에서 각각 $93.7{\pm}2.3%$와 $100.0{\pm}1.3%$이었다. Amisulbrom을 기준량으로 1회 살포 시 엇갈이배추 중의 생물학적 반감기는 포장 1 및 2에서 각각 3.7일과 4.1일로 계산되었으며, 증체량에 따른 희석효과가 amisulbrom의 잔류량 감소에 주된 인자로 작용하지는 않았다. 잔류감소 회귀식을 이용한 생산단계 농약 잔류허용기준은 수확 10일전 8.86~9.47 mg/kg, 또는 5일전에 4.21~4.35 mg/kg으로 제안하였다.

• 원예과학기술지
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• 제34권4호
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• pp.644-654
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• 2016

본 연구는 엇갈이배추 재배기간 중 mandelamide계 살균제인 mandipropamid를 수확 10일전 1회 살포한 후 각각 0(2시간 이내), 1, 3, 5, 7, 및 10일 후에 엇갈이배추 시료를 채취하여 mandipropamid 잔류량을 분석, 통계학적 생물학적 반감기를 산출하여 생산단계 농약잔류허용기준(Pre-Harvest Residue Limit; PHRL)을 설정하고자 하였다. Mandipropamid의 평균 회수율은 0.4 및 $2.0mg{\cdot}kg^{-1}$의 두 수준에서 각각 $88.2{\pm}3.2%$와 $92.2{\pm}2.0%$이었으며, 분석정량한계는 $0.04mg{\cdot}kg^{-1}$이었다. Mandipropamid를 기준량으로 1회 살포 시 엇갈이배추 중의 생물학적 반감기는 포장 1 및 2에서 각각 3.9일과 4.0일 이었고, 생체중 증가가 mandipropamid의 잔류량 감소에 상당한 영향을 나타내었다. 잔류감소 회귀식을 이용한m andipropamid의 생산단계 잔류허용기준은 수확 10일전의 경우 $11.07-12.19mg{\cdot}kg^{-1}$ 수준, 수확 5일전의 경우 $5.76-6.05mg{\cdot}kg^{-1}$ 수준인 것이 바람직한 것으로 판단 되었다.

• 농약과학회지
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• 제16권3호
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• pp.230-235
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• 2012

본 실험은 포장과 살포기의 차이가 고추 열매 중 농약 잔류량에 미치는 영향을 구명하고자 하였다. 위치가 다른 세 농가 포장에서 비슷한 시기에 정식한 고추를 대상으로 동일한 분무기와 노즐로 약제 처리 후 1일차의 농약 잔류량은 통계처리로 확인하여 차이가 없었다. 시료 채취시 고추나무 외부의 고추 중 잔류량은 내부의 고추 보다 2배 이상 많아 시료 채취의 위치가 고추 중 잔류량 변이의 요인이 되었다. 배부식 동력분무기와 압축식 인력분무기 사용에 따른 농약잔류량 차이는 동력분무기가 인력분무기를 사용할 때 보다 1.7배 높은 잔류농도를 보였는데 이는 약제 살포시 인력분무기의 상용압력보다 2배 정도 높은 동력분무기 압력과 노즐의 영향으로 판단되었다.

• 대한화학회지
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• 제63권5호
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• pp.335-341
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• 2019

배양한 셀레늄 강화 스피룰리나를 ICP-MS에서 동위원소희석법을 이용하여 총농도를 정량하였고, HPLC-ICP/MS를 이용하여 낮은 분자량의 셀레늄 화학종들을 각각 분리하고 정량하였다. 셀레노 화합물들은 일차적으로 증류수를 이용하여 추출하였고 이차적으로는 단백질 분해 효소 protease XIV를 이용하여 단백질들을 분해한 뒤에 추출하였다. 배양한 스피룰리나의 셀레늄 총량은 $414.9{\pm}4.0mg\;g^{-1}$으로 나타났고 증류수로 추출하였을때, 분리한 상등액과 가라앉은 residue는 각각 $318.3mg\;g^{-1}$과 $90.9mg\;g^{-1}$으로서 총량의 약 77%와 22%로 분포되어 있었다. 셀레늄 화학종의 분포는 상등액에서는 주로 selenate ($222.7mg\;g^{-1}$)가 존재하였고 단백질 가수분해를 시키고 조사한 결과, 유기셀레늄들 SeMet ($12.13mg\;g^{-1}$)과 SeCys ($15.20mg\;g^{-1}$)이 추가로 나타났다. Residue에서는 무기 셀레늄이 거의 검출되지 않았고 SeCys과 SeMet이 나타났으며 단백질 분해효소를 사용하여 추출한 경우, 더 많은 셀레노 아미노산들, SeCys ($9.35mg\;g^{-1}$)과 SeMet ($18.23mg\;g^{-1}$), 및 MeSeCys ($1.5mg\;g^{-1}$)이 검출되었다. 무기셀레늄은 주로 스피룰리나의 표면에 흡착된 것으로 보이며 증류수 추출로 이들을 충분히 제거할 수 있었고 결과, residue에서는 대부분 유기셀레늄(99% 이상)만 존재하였다.

• 농업과학연구
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• 제43권4호
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• pp.634-640
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• 2016

The objective of this study was to evaluate the effectiveness of using HR-GC/MS for the rapid screening of dieldrin residues in soils. Persistent organic pollutants (POPs) of organochlorine pesticides such as dieldrin, were analyzed in sedimentary rock and granite rock collected from greenhouses, Niigata, Japan. Dieldrin remains in Japanese farming soils, more than 40 years after their use as insecticides was prohibited. The averages in soil moisture ranged from 2.79% to 7.20% in soils derived from sedimentary rock and from 25.59% to 31.40% in soils derived from granite rock. Mean concentrations of dieldrin residues in sedimentary rock and granite rock were $39.7ng\;g^{-1}$ and $40.51ng\;g^{-1}$, respectively. Dieldrin residue was detected at a slightly higher concentration in granite rock than sedimentary rock samples. There was no consistency between the two soils or between surface and subsurface soils. The coefficients of variation of the two soils were 10.6% and 8.7%, respectively. These results suggest that our high-resolution mass spectrometry detector (HR-GC/MS) is effective at analyzing residual organochlorine pesticides in soil. In order to increase the precision and sensitivity for chemical analysis of POPs, high-resolution gas chromatography coupled with a HR-GC/MS is highly recommended.

• Agribusiness and Information Management
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• 제3권1호
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• pp.11-22
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• 2011

This study describes the development of a web-based system that collects all data generated in the research conducted to set pre-harvest residue limits (PHRLs) for agricultural product safety control. These data, including concentrations of pesticide residues, limit of detection, limit of quantitation, recoveries, weather charts, and growth rates, are incorporated into a database, a regression analysis of the data is performed using statistical techniques, and the PHRL for an agricultural product is automatically computed. The development and establishment of this system increased the efficiency and improved the reliability of the research in this area by standardizing the data and maintaining its accuracy without temporal or spatial limitations. The system permits automatic computation of the PHRL and a quick review of the goodness of fit of the regression model. By building and analyzing a database, it also allows data accumulated over the last 10 years to be utilized.

• Journal of Welding and Joining
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• 제35권3호
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• pp.21-27
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• 2017

A soldering temperature of ($235{\pm}3$) $^{\circ}C$ is described in ISO 9455-15 for the copper corrosion test. However, this temperature is not suitable for performing lead-free solder pastes. We evaluated the compatibility of a lead-free solder paste in the experimental conditions of (Liquidus temperature + ($35{\pm}3$)) $^{\circ}C$. Based on the results after a Cu corrosion test, a proper temperature for Pb-free soldering was (melting point+($35{\pm}3$)) $^{\circ}C$. Criteria used to evaluate corrosion due to discoloration of flux residue is described in ISO 9455-15, but a more quantitative evaluation standard is needed. In this study, experimental error level was estimated by analyzing flux residue after a corrosion test for 72, 500 hours of specimens using EDS analysis with acceleration voltage. It was determined that the copper area at the flux residue boundary is suitable for the EDS analysis area.

• Mass Spectrometry Letters
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• 제10권2호
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• pp.50-55
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• 2019

The fragmentation statistics of ion trap CID (Collision-Induced Dissociation) spectra using 87,661 tandem mass spectra of doubly charged tryptic peptides are analyzed here. In contrast to the usual method of using intensity information, the frequency of occurrence of fragment ions, with respect to the position of the cleavage site and the residues at these sites is studied in this paper. The analysis shows that the frequency of occurrence of fragment ion peaks is more towards the middle of the peptide than its ends. It was noted that amino acid with an aromatic and basic side chain at N- & C- terminal end of the peptide stimulates more peaks at the lower end of the spectrum. The residue pair effect was shown when the amide bond occurs between acidic and basic residues. The fragmentation at these sites (D/E-H/R/K) stimulates the generation of the y-ion peak. Also, the cleavage site H-H/R/K stimulates the generation of b-ions. K-P environment in the peptide sequence has more tendency to generate y-ions than b-ions. Statistical analysis helps in the visualization of the CID fragmentation pattern. Cleavage pattern along the length of the peptide and the residue pair effects, enhance the knowledge of fragmentation behavior, which is useful for the better interpretation of tandem mass spectra.

• 한국환경농학회지
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• 제42권1호
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• pp.71-81
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• 2023

An accurate and easy-to-use analytical method for determining isocycloseram and its metabolites (SYN549431 and SYN548569) residue is necessary in various food matrixes. Additionally, this method should satisfy domestic and international guidelines (Ministry of Food and Drug Safety and Codex Alimentarius Commission CAC/GL 40). Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) was used to determine the isocycloseram and its metabolites residue in foods. To determine the residue and its metabolites, a sample was extracted with 20 mL of 0.1% formic acid in acetonitrile, 4 g magnesium sulfate anhydrous and 1 g sodium chloride and centrifuged (4,700 G, 10 min, 4℃). To remove the interferences and moisture, d-SPE cartridge was performed before LC-MS/MS analysis with C₁₈ column. To verify the method, a total of five agricultural commodities (hulled rice, potato, soybean, mandarin, and red pepper) were used as a representative group. The matrix-matched calibration curves were confirmed with coefficients of determination (R²) ≥ 0.99 at a calibration range of 0.001-0.05 mg/kg. The limits of detection and quantification were 0.003 and 0.01 mg/kg, respectively. Mean average recoveries were 71.5-109.8% and precision was less than 10% for all five samples. In addition, inter-laboratory validation testing revealed that average recovery was 75.4-107.0% and the coefficient of variation (CV) was below 19.4%. The method is suitable for MFDS, CODEX, and EU guideline for residue analysis. Thus, this method can be useful for determining the residue in various food matrixes in routine analysis.

• 분석과학
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• 제9권2호
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• pp.1033-1060
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• 1996