• Journal of Food Hygiene and Safety
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• v.29 no.2
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• pp.131-140
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• 2014

The objective of this study was to develop a simultaneous method of 8 penicillin antibiotics including amoxicillin, ampicillin, cloxacillin, dicloxacillin, nafcillin, oxacillin, penicillin G and penicillin V in meat using LC-MS/MS. The procedure involves solid phase extraction with HLB cartridge and subsequent analysis by LC-MS/MS. To optimize MS analytical condition of 8 compounds, each parameter was established by multiple reaction monitoring in positive ion mode. The chromatographic separation was achieved on a $C_{18}$ column with a mobile phase of 0.05% formic acid and 0.05% formic acid in acetonitrile at a flow rate of 0.2 mL/min for 20 min with a gradient elution. The developed method was validated for specificity, linearity, accuracy and precision in beef, pork and chicken. The recoveries were 71.0~106%, and relative standard deviations (RSD) were 4.0~11.2%. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.003~0.008 mg/kg and 0.01~0.03 mg/kg, respectively, that are below maximum residue limit (MRL) of the penicillins. This study also performed survey of residual penicillin antibiotics for 193 samples of beef, pork and chicken collected from 9 cities in Korea. Penicillins were not found in all the samples except a sample of pork which contained cloxacillin (concentration of 0.08 mg/kg) below the MRL (0.3 mg/kg).

• Analytical Science and Technology
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• v.22 no.6
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• pp.488-497
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• 2009

In this study, analytical methodology for several organic fatty acids (OFA: propionic acid (PA), butyric acid (BA), isovaleric acid (IA), and valeric acid (VA)) designated as new offensive odorants in Korea (as of year 2010) was investigated along with some odorous VOCs (styrene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol). For this purpose, working standards (WS) containing all of these 13 compounds were loaded into adsorption tube filled with Tenax TA, and analyzed by gas chromatography (GC) system thermal desorber interfaced with. The analytical sensitivities of organic fatty acids expressed in terms of detection limit (both in absolute mass (ng) and concentration (ppb)) were lower by 1.5-2 times than other compounds (PA: 0.24 ng (0.16 ppb), BA: 0.19 ng (0.11 ppb), IA: 0.15 ng (0.07 ppb), and VA: 0.28 ng (0.13 ppb)). The precision of BA, IA, and VA, if assessed in terms of relative standard error (RSE), maintained above 5%, while the precison of other compounds were below 5%. The reproducibility of analysis improved with the aid of internal standard calibration (PA: $1.1{\pm}0.4%$, BA: $10{\pm}0.46$, IA; $12{\pm}0.3%$, VA: $4{\pm}0.1%$), respectively. The results of this study showed that organic fatty acid can be analyzed using adsorption tube and thermal desorber in a more reliable way to replace alkali absorption method introduced in the odor prevention law of the Korea Ministry of Environment (KMOE).

• Analytical Science and Technology
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• v.18 no.5
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• pp.396-402
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• 2005

We try to look for optimum conditions of pre-reductants like L-Cysteine, KI and $FeSO_4$ when analyzing inorganic arsenic by using hydride generation-atomic absorption spectrometry, and run a comparative study of effect in the analysis of them. Also, we separated and analyzed only inorganic arsenic by using $H_2SO_4$-trap to eliminate organic arsenic which are MMA(monomethylarsonate) and DMA(dimethylarsinate). Under the conditions of mixture acid of 1.8 M HCl and 0.08 M $HNO_3$, arsenic standard solution of 20 ppb have more higher absorbance than without adding acid. In case of L-Cysteine, As(V) completely reduces into As(III) when 0.5 g of L-Cysteine is reacted more than 30 mins. in weak acid condition of approximately 0.07 M $HNO_3$ or HCl. In the event of KI, As(V) completely reduces into As(III) when 3 g of KI is reacted more than 1hour in acid condition of 0.8 M $HNO_3$. On the occasion of $FeSO_4$, the inside of tube is blocked by precipitation by mixture reaction of $NaBH_4$ and $Fe^{2+}$, therefore, comparing to other pre-reductants, reproducibility of efficiency of reducing As(V) to As(III) is low. To evaluate the accuracy of the analytical results, we use NIST SRM 1643C Trace Elements in Water ($82.1{\pm}1.2ng/mL$). The results are satisfactory.

• Journal of the Korean Chemical Society
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• v.40 no.8
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• pp.542-548
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• 1996

Electrodes modified with threonine, methionine and serine as ligands, which are incorporated by ion exchange into a polycationic film of electropolymerized $[Ru(v-bpy)_3]^{2+}$, have been employed in the determination of mercury in solution. The redox response of the surface-immobilized mercury/ligand complex was used as the analytical signal. When the polymeric film was electropolymerized, the supporting electrolytes were TBAP and $KPF_6$ to compare the morphology and anodic stripping of resulted polymer electrodes. At the case of the latter, the film had high porosity to give an easy incorporation of dopant anions into polymeric film matrix and a high sensitivity in determination of mercury ion. Especially, this polymer modified electrode exhibited possibility of multiple use in mercury determination over ten times. In all cases, calibration curves which were plotted by log of the surface coverage-normalized redox response vs. log[Hg] exhibited an excellent correlation (r=0.99) for mercury concentrations ranging from 1.0{\times}10^{-8}{\sim}1.0{\times}10^{-2}M$. At these curves relative standard deviation was 5∼8% and saturation response was not observed at high concentration region. Serine of the employed ligands had the best sensitivity in analytical application, which had greater stability constant in forming a complex with mercury than others as $pK_{Hg}=8.54$. The formation constants of threonine and methionine were respectively 7.04 and 7.80.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.108-114
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• 2012

Purpose: Immunosorbent assay most commonly used in the laboratory and commercial third-party quality control material is a substance that provided by BIO-RAD. However, in Reference Sheet by radioimmunoassay test kit or a measuring device for the mention of Acceptable Range is somewhat lacking. Radioimmunoassay for the inspection of test results by setting Acceptable Range to increase the objectivity of the recommendations on the data accumulated by the manufacturer listed in the Reference Sheet is to be issued. Materials and Methods : In our hospital since 2009 partially BIO-RAD using quality control materials in 2011, excluding certain items, some items were most of the BIO-RAD third-party quality control materials are used. Thus, internal quality control data accumulated BIO-RAD's Unity Real Time program by using the items were measured. Results : BIO-RAD using quality control material items were about 50 of the 20 Point Data averages, standard deviations, variation coefficients were calculated to measure the Acceptable Range of kit, automated immunoassay attributed Roche Elecsys / E170 / cobas e Systems the measures and compared. Conclusions : BIO-RAD QC materials commonly used hospital and peer group by setting the measurement kit, suitable for laboratory equipment for radioimmunoassay of Acceptable Range manufacturer recommendation to increase the objectivity of the test results by national and international recognition for radioimmunoassay should seek to increase.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.374-378
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• 2008

For the standard method of collecting the run-off, it is consumed the high cost and much effort to install and to manage this instrument. Because the all the soil and water from reservoir tank must be eliminate after their measurement of amount of soil loss and run-off and installed the reservoir tank at regular size in the experimental field. Therefore, objective of this study was to compare its efficacy between the standard method and a flow rotate divider for ontinuously collecting and measuring the soil loss and run-off in order to conveniently conduct the field experiment of the lysimeters. For collecting the sampling of soil loss and run-off from agricultural land with invariable ratio, a flow rotate divider was consisted with a 8 blades of round plate sloped in order to collect the invariable ratio of soil and water at lowest part from round plate by the law of gravity. For comparing its accuracy in the batch scale experiment, it shown that there was significantly a positive linear corelation ($r=0.997^{***}$) between flowing and sampling amounts with adjusting the range from 1 to $10L\;min^{-1}$ with flowing rate. In collecting ratio in the field experiment, it observed that the more its accuracy had, the more soil loss and run-off.

• Journal of fish pathology
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• v.20 no.2
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• pp.139-145
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• 2007

To decrease stress in eel (Anguilla japonica) during its culture or transportation, aspirin (ASA) known as analgesic, antiinflammatory and antithrombic agent was administrated by dipping or oral routes. Concentrations of aspirin (ASA) and salicylic acid (SA) in eel plasma were simultaneously measured by a high performance liquid chromatography (HPLC). The plasma was acidified with 0.2 M HCl and 0.2 M orthophosphoric acid, and mixed with acetonitrile. ASA and SA extracted with acetonitrile were analyzed by the HPLC equipped with reversed phase Novapak C18 column (4 ㎛ silica, 150×4 mm) and UV detector(237 nm). The mobile phase consisted of 740 ㎖ water, 900 ㎕ orthophosphoric acid (85%) and 180 ㎖ acetonitrile. The retention times of ASA, SA and 2-methylbenzoic acid(MBA) were 4.8 min, 8.4 min and 11.5 min, respectively. The limit of quantification was 0.01 ㎍/㎖ for SA and 0.05 ㎍/㎖ for ASA. The mean recovery from eel plasma was 70.8～99.6% for ASA and 95.2～100.3% for SA. This HPLC method was applied to analyze ASA and SA of eel plasma after either dipping in a concentration of 20 ppm or feeding the feed supplemented with 50 ㎎/kg BW. Only SA was detected in eel plasma after the administration of ASA by dipping or oral routes because the drug was quickly decomposed into SA in eel plasma. The amount of SA in eel plasma reached the highest value at 3hr in dipping and 7 days in oral administration. When the ASA-administrated eel were kept in ASA free aquaria, 0.02-0.03 ㎍/㎖ of SA were detected 48 hr after the administration in both routes.

• The Korean Journal of Pesticide Science
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• v.9 no.2
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• pp.159-165
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• 2005

A sensitive derivatization method by using the TFE/TFAA as derivative reagent is proposed for the determination of acidic herbicides in water, by using this method, method detection limits are improved by 10 times and sample volumes are decreased by 5 times compared with other methods such as U.S. EPA and SPEED 98. And also, in order to suggest higher creditable standard operating procedure (SOP), intra- and inter-lab validation test carried out by four laboratories include our lab. The results of intra and inter-lab validations in same experimental conditions show good linearity in given range of concentrations as a $0.1{\sim}10.0$ ng/ml, and range of accuracies and precisions show $-20.5{\sim}12.2$ bias%, $0.55{\sim}24.48%$ (for intra-lab validation) and $-6.66{\sim}0.80 bias%$, $1.92{\sim}13.86%$ (for inter-lab validation), respectively.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.98-98
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• 2003

무순에는 비타민 C가 많이 들어 있어 겨울철 비타민 공급원뿐만 아니라 디아스타제라는 효소가 들어 있어 소화를 촉진시키는 역할을 한다. 그 외에도 거담제 및 건위제 작용을 하고 음주로 인한 토혈해소, 천식에도 좋아 약용하기도 한다. 본 연구에서는 이용가치는 적지만 농가 소득증대에 기여 할 수 있으며 소화를 촉진시키는 무순, 또는 무싹기름이라고 일컬어지는 무순을 추출용매에 따라 생리활성 효과 분석하고 영양학적 가치가 가장 높은 시기의 무순을 선택함으로써 올바른 섭취의 기초자료를 마련하고 그 기능성을 확인하여 기능성 식품소재 및 기능성 화장품 소재로써의 활용을 검토하고자 하고자 한다. 무순을 4일, 8일, 12일에 따라 incubator에 배양하여 시기별로 채취하여 동결건조 한 후 70% Ethanol, 80% Methanol, 75% acetone, 열수로 환류 추출한 후 시료로 사용하였다. 각 용매 추출물에 대해 DPPH free radical 소거능 실험에서는 acetone 추출물에서 89.18%로 가장 높은 전자공여능을 나타냈으며 각각의 추출용매에서 성장 4일과 12일의 무순에서 높은 전자공여능을 보였다. 아질산염 소거능에서는 pH 1.2의 조건에서 가장 높은 아질산염 소거능을 보였고, 열수 추출물에서 89.70%로 가장 높은 소거능을 보였다. pH 4.2조건에서는 열수추출물의 소거능이 가장 좋았고, pH 6.0 조건에서는 가장 낮은 소거능을 보였으며, Ethanol 과 Methanol 추출물에서 23.55∼37.41%의 소거능을 보였다. SOD유사활성은 성장 8일에서 모두 낮은 활성을 보였으며, 성장 4일과 성장 12일의 무순에서는 큰 차이를 보이지 않았지만, Methanol 추출물중 성장 12일에서 27.41%의 SOD유사활성을 보였다.ic acid는 28.8∼51.7 mg%, 미강에서 321.4∼438.4 mg% 범위로 나타났다. 현미, 백미 및 미강에 함유된 총 폴리페놀의 함량을 표준 페놀화합물로 카테친을 사용하고 비색법에 의하여 측정하였을 때 오대 현미의 폴리페놀 함량은 78.4 mg%, 남평 현미 88.8 mg% 였다. 도정한 백미 중의 총 폴리페놀 함량은 30.3∼56.9 mg%, 미강이 541.5∼472.6 mg%의 범위였다. 이상과 같이 쌀에는 phenolic acid 및 총 폴리페놀이 상당량 함유되어 있으며 특히 배유보다는 강층에 많이 존재하므로 이들 성분의 효율적인 이용을 위한 쌀의 섭취방안이 필요한 것으로 나타났다. 유의적인 상관관계를 나타내고 있어 백편의 조직감은 Compression force 와 Work ratio로 대치할 수 있을 것이라고 사료된다. 수분함량은 기계적 검사보다 관능검사와 더욱 높은 상관관계를 나타냈다.내었다. 항균활성이 우수한 생약재를 농도별로 활성을 조사한 결과, 물 추출물과 10% Ethanol 추출물 모두 낮은 농도에서도 우수한 항균활성을 나타내었다.취와 함께 점질성 갈변물질이 생성되었다. 이와 같은 결과로 볼 때, BAAG의 처리는 BAAC의 경우보다 가격은 저렴하면서도 항균력은 우수한 천연 항균복합제재로써 농산물 식품원료에 적용하여 선도유지 기간을 연장할 수 있는 효과를 기대할 수 있었다. 과일 등의 포장제로서 이용할 가능성을 확인하였다.로 [-wh] 겹의문사는 복수 의미를 지닐 수 없 다. 그러면 단수 의미는 어떻게 생성되는가\ulcorner 본 논문에서는 표면적 형태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elem

• Journal of Korean Society of Environmental Engineers
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• v.37 no.5
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• pp.262-268
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• 2015

This study established an analytical method to simultaneously determine six organophosphorous pesticides [methyldemetone-S, diazinon, fenitrothion, parathion, phentoate, and O-ethyl O-(4-nitrophenyl) phenylphosphonothioate (EPN)] and carbaryl in water using a gas chromatography/mass spectrometry (GC/MS) system coupled with on-line micro extraction by packed sorbent (MEPS) and programmed temperature vaporizer (PTV) injector. Polystyrene divinylbenzene (PDVB) was used as a sorbent of MEPS. The effects of elution solvents, pH, elution volume and draw-eject cycles of samples on sample pretreatment process were investigated. Also, quality assurance and quality control (QA/QC) and the recovery of the pesticides in environmental samples were evaluated. The elution was performed using $30{\mu}L$ of a mixed solvent (acetone : dichloromethane = 80 : 20 (v/v)). Sample pretreatment processes were optimized with seven cycles of draw-eject of sample (1 mL) spiking an internal standard and sulfuric acid. At lower pH, the analytical sensitivity of diazinon decreased, but that of carbaryl increased. The method detection limit and the limit of quantification for this method were 0.02~0.18 and $0.08{\sim}0.59{\mu}g/L$, respectively. The method precision and accuracy were 1.5~11.5% and 83.3~129.8%, respectively, at concentrations of $0.5{\sim}5.0{\mu}g/L$. The recovery rates for all the pesticides except carbaryl in various environmental samples ranged 75.7~129.3%. The recovery rate of carbaryl in effluent sample was over 200% whereas carbaryl in drinking water, groundwater, and river water were in the acceptable range.