• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3755-3759
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• 2010

A on-line SPE (solid phase extraction)-HPLC preconcentration method was developed for the determination of phenolic compounds at trace levels in environmental water sample. XAD-4 and Dowex 1-X8 were used as sorbent in the on-line SPE-HPLC method for the selective enrichment of nine phenolic compounds, which are included in the priority pollutants list of the US EPA. Also alumina prefiltering considerably reduced the amount of interfering peaks due to humic substances that could accumulated due to the preconcentration step and prevent quantification of polar phenolic compounds in environmental water samples. This method was used to determine the phenolic compounds in tap and river water and superiority to the US EPA 625 method in its enrichment factor, pretreatment time, recoveries, and detection limit. The limits of detection were in the range of $0.3-0.9\;{\mu}g/L$ in tap water sample.

• 대한환경공학회지
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• 제35권2호
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• pp.75-83
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• 2013

본 연구는 기존의 고상추출(SPE) 과정을 분석장비인 LC/MSD에 on-line으로 연결함으로써 cartridge의 건조를 막아 target 물질의 손실을 최대한 억제하였으며 11종의 PFCs에 대해 실제 matrix가 있는 낙동강 원수를 이용한 실험에서 $80.4{\pm}5.2%{\sim}109.5{\pm}1.4%$ 범위의 높은 회수율을 구할 수 있었다. 낙동강에서의 PFCs 분포를 조사한 결과 하수처리장 방류수의 영향을 받는 지역(진천천과 금호강 하류)은 고농도의 PFCs가 검출되었으며, 낙동강 하류의 매리원수에서는 검출농도가 급격히 감소하여 PFOA만 8.0 ng/L의 농도로 검출되었다. 외국의 PFCs 검출현황을 보고한 연구결과들과 비교해 볼 때 낙동강 지류에서는 비교적 높은 농도로 PFCs가 검출되어 안심할 수 있는 수준은 아니었으며, 낙동강 본류의 경우도 여러 지역의 상수원으로 이용되기 때문에 주기적인 모니터링이 필요한 것으로 나타났다.

• 약학회지
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• 제39권4호
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• pp.395-400
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• 1995

The sorption and desorption properties of four adsorbents were evaluated for the trace enrichment of clobazam from biological samples. Graphitized carbon black(GCB) gaved the highest dynamic adsorption coefficient. Among the six organic solvents examined, acetone gave the highest desorption coefficient for the clobazam adsorbed on GCB. Using the GCB column, the optimum elution volume of the eluting solvent was evaluated from the on-line monitored breakthrough curve for clobazam. When GCB as the solid adsorbent and acetone as the eluting solvent were used for the solidphase extraction of clobazam from serum, the recoveries were higher than 83% with good reproducibility in the concentration range of 20-50 $\mu\textrm{g}$/ml.

• 한국환경과학회지
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• 제24권12호
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• pp.1569-1582
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• 2015

The analytical method for 16 organophosphorus pesticides was developed in this study. The 16 organophosphorus pesticides were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) using on-line solid phase extraction (on-line SPE) with PLRP- S cartridge. Analysis of all analytes in the MS/MS was processed in the electrospray ioni-zation (ESI) positive mode. They are Azinphos ethyl, Chlorfenvinphos, Ethion, Famphur, Phosmet, Phosphamidon, Terbufos, Aspon, Chlorpyrifos-methyl, Crotoxyphos, Dichlofenthi-on, Dicrotophos, Fonofos, Thionazin, Dimethoate and Iprobenfos. Limits of detection (LODs) and Limits of quantification(LOQs) were obtained as 0.8~2.0 ng/L and 2.6~6.4 ng/L, respectively. All compounds were not detected at the 8 sampling points of the raw water and clean water.

• 분석과학
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• 제8권4호
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• pp.539-543
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• 1995

The on-line SPE-HPLC coupling system was developed for the efficient separation and determination of trace pesticides, such as phenoxyacetic acids and esters, and triazines in aqueous solutions. By using the developed SPE-HPLC on-line system, the band broadening usually observed in single precolumn switching mode was greatly reduced, consequently, the quantitative determination of trace pesticides could be achieved, Besides, since most of the analytes preconcentrated by SPE column could be injected directly into HPLC system, the limit of detection can be improved down to ppt level.

• Animal Bioscience
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• 제36권7호
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• pp.1130-1142
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• 2023

Objective: Cow urine possesses several bioactive properties but the responsible components behind these bioactivities are still far from identified. In our study, we tried to identify the possible components behind the antimicrobial activity of cow urine by exploring the peptidome and metabolome. Methods: We extracted peptides from the urine of Sahiwal cows belonging to three different physiological states viz heifer, lactation, and pregnant, each group consisting of 10 different animals. The peptides were extracted using the solid phase extraction technique followed by further extraction using ethyl acetate. The antimicrobial activity of the aqueous extract was evaluated against different pathogenic strains like Staphylococcus aureus, Escherichia coli, and Streptococcus agalactiae. The safety of urinary aqueous extract was evaluated by hemolysis and cytotoxicity assay on the BuMEC cell line. The urinary peptides were further fractionated using high-performance liquid chromatography (HPLC) to identify the fraction(s) containing the antimicrobial activity. The HPLC fractions and ethyl acetate extract were analyzed using nLC-MS/MS for the identification of the peptides and metabolites. Results: A total of three fractions were identified with antimicrobial activity, and nLC-MS/MS analysis of fractions resulted in the identification of 511 sequences. While 46 compounds were identified in the metabolite profiling of organic extract. The urinary aqueous extract showed significant activity against E. coli as compared to S. aureus and S. agalactiae and was relatively safe against mammalian cells. Conclusion: The antimicrobial activity of cow urine is a consequence of the feeding habit. The metabolites of plant origin with several bioactivities are eliminated through urine and are responsible for their antimicrobial nature. Secondly, the plethora of peptides generated from the activity of endogenous proteases on protein shed from different parts of tissues also find their way to urine. Some of these sequences possess antimicrobial activity due to their amino acid composition.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1783-1790
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• 2013

A simultaneous analytical method has been developed for the fluorimetric determination of haloacetonitriles (HANs) [dichloroacetonitrile (DCAN), trichloroacetonitrile (TCAN), dibromoacetonitrile (DBAN), haloacetamides [dichloroacetamide (DCAD), and trichloroacetamde (TCAD)] in drinking water by using the combined on-line perconcentration/reversed phase liquid chromatography (RPLC)-postcolumn detection system. This on-line perconcentration system was achieved by employing a precolumn packed with a commercial solid phase extraction (SPE) sorbent for the enrichment and purification of the target analytes. The haloacetonitriles and haloacetamides were separated on CN analytical column in a 7.5% methanol-0.02 M phosphate buffered mobile phase at pH 3. The column effluents were reacted with postcolumn reagents of ophthaldialdehyde (OPA) and sulfite ion at pH 11.5, to produce a highly fluorescent isoindole fluorophore, which were measured with a fluorescence detector. Under the optimized conditions for RPLC and the postcolumn derivatization system all of the coefficient of determination of the standard calibration curves for the target analytes were over 0.99 and had a linear range from 5 to 100 ${\mu}g/L$. The detection limits showed 1.6 ${\mu}g/L$ for DCAD, 0.1 ${\mu}g/L$ for TCAD, 0.6 ${\mu}g/L$ for DCAN, 1.6 ${\mu}g/L$ for TCAN and 1 ${\mu}g/L$ for DBAN, and the recoveries were ranged from 64 to 99% except for DCAD with precisions less than 4.9% in distilled water, and from 72(${\pm}4%$) to 116%(${\pm}2%$) in tap water.

• 한국연초학회지
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• 제30권2호
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• pp.117-124
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• 2008

A solid phase microextraction (SPME) method in combination with gas chromatography/mass spectrometric techniques was used for the extraction and quantification of 12 selected agrochemical residues in tobacco. The parameters such as the type of SPME fiber, adsorption/desorption time and the extraction temperature affecting the precision and accuracy of the SPME method were investigated and optimized. Among three types of fibers investigated, polyacrylate (PA), polydimethylsiloxane (PDMS) and polydimethylsiloxane-divinylbenzene (PDMS-DVB), PDMS fiber was selected for the extractions of the agrochemicals. The SPME device was automated and on-line coupled to a gas chromatograph with a mass spectrometer. Mass spectrometry (MS) was used and two different instruments, a quadrupole MS and triple quadrupole MS-MS mode, were compared. The performances of the two GC-MS instruments were comparable in terms of linearity (in the range of 0.01$\sim$0.5 $\mu$g/mL) and sensitivity (limits of detection were in the low ng/mL range). The triple quadrupole MS-MS instrument gave better precision than that of quadrupole MS system, but generally the relative standard deviations for replicates were acceptable for both instruments (< 15%). The LODs was fully satisfied the requirements of the CORESTA GRL. Recoveries of 12 selected agrochemicals in tobacco yielded more than 80% and reproducibility was found to be better than 10% RSD so that SPME procedure could be applied to the quantitative analysis of agrochemical residues in tobacco.

• 분석과학
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• 제31권1호
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• pp.39-46
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• 2018

온라인 고체상 추출을 이용한 LC/MS/MS를 사용하여 carbaryl과 유기인계 농약 7 종을 동시에 분석하는 방법을 확립하였다. 분석 대상농약은 carbaryl, diazinon, methyl-demeton, fenitrothion, malathion, parathion, phenthoate, EPN 등 8 종이다. 본 연구에서는 온라인 고체상 추출과 LC/MS/MS의 ESI positive mode로 전처리 없이 물 시료 $500{\mu}L$를 직접 주입하여 10분안에 분석하였다. 농약 8 종의 회수율은 86.8~100 % 였고, 정확도는 90.6~98.8 %로 90 %이상이었고, 정밀도는 1.3~5.2 %로 나타났으며 검출한계 및 정량한계는 각각 $0.05{\sim}0.28{\mu}g/L$, $0.16{\sim}0.89{\mu}g/L$ 였다. $0.5{\mu}g/L$에서 $8.0{\mu}g/L$까지 다섯 개의 농도로 검량선을 작성한 결과 모든 물질의 상관계수(r2)가 0.99이상을 나타냈다. 방법의 유효성 평가를 한 결과 모든 내용에서 적합하므로확립한 분석방법으로 수질 시료에서 농약을 조사한 결과 모두 검출되지 않았다.

• 분석과학
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• 제7권1호
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• pp.33-39
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• 1994

환경오염수에 미량 존재하는 페놀류를 정량하기 위한 분석법의 개발을 위하여 8가지 페놀류를 대상 시료로, 고체상 추출법을 이용한 전처리 방법을 연구하였다. XAD-4와 Dowex $1{\times}8$ 수지를 연결하여 HPLC로 분석하는 온 라인 시스템을 만들어 농축과 분리의 선택성을 높이며 자동화에 중점을 두었다. 시료를 XAD-4 컬럼에 용리시켜 페놀류를 분자흡착으로 농축시킨 후 염기성 아세토니트릴을 용리시켜 탈착시키고 계속해서 Dowex $1{\times}8$ 컬럼에 음이온교환으로 페놀류만을 선택적으로 재흡착시킨다. Dowex $1{\times}8$ 컬럼에 재흡착된 페놀류를 물로 세척한 후 HCl을 포함하는 메탄올 용액으로 재탈착시킨다. 전처리 단계는 switching 밸브에 의해 온 라인으로 연결하였고 탈착된 페놀류를 HPLC에 직접 주입하여 신속하고 신뢰성 있는 정량이 가능하였다. 각 페놀류는 90% 이상의 회수율을 나타내었다. 본 분석법의 활용성을 평가하기 위해 환경오염수에서 페놀류와 공존 가능한 유기 화합물들을 첨가시켜 조제한 실험실적 오염수를 만들어 방해 효과를 조사한 결과, 페놀류만을 선택적으로 농축-분석할 수 있었다.