• 한국환경과학회지
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• 제11권12호
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• pp.1299-1305
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• 2002

Thirty sediment samples of the <63${\mu}{\textrm}{m}$ fraction collected from the southwestern coast of Korea were analysed for their heavy metal (Fe, Mn, Cr, Co, Cu, Ni, Zn and Pb) concentration. The results show that sediment texture plays a controlling role on the total metal concentrations and their spatial distribution. A single lM HCl extraction procedure was used in order to assess the environmental risk of heavy metals in bottom sediments. The non-residual fraction was the most abundant pool for Mn and Pb in most samples, which means that this metals are highly avaliable in these sediments. Cr, Ni, Fe, Co, Zn and Cu were mainly associated with the residual fraction, suggesting that their concentrations are controlled significantly by transport processes with the fine particles as carriers from diffuse pollution source. Concentration enrichment ratios(CER) were calculated from the non-residual contents and their values allowed us to classify the sediments according to their environmental risk.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2004년도 춘계임시총회 및 제23회 학술대회
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• pp.218-226
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• 2004

Solvent extraction and stripping experiments were conducted to separate iron from a spent $FeCl_3$ etching solution containing nickel. In the extraction, PC88A, MIBK and Alamine336 were tested as an extractant in various diluents. Alamine336 salt in toluene led to the highest extraction percentage of iron. Stripping percentage of iron from the loaded organic by Alamine336 increased with decreasing HCl conentration of stripping solution and with increasing volume ratio of aqueous to organic. In the operation of bench scale mixer-settler, 7 extraction stage with 1.0M Alamine336 salt in toluene and 10 stripping stage with 0.01M HCl solution resulted in a stripped solution with 133g/L of iron and in a raffinate with most of nickel together with a small amount of iron when the flow rate ratio of organic to aqueous was 7.

• Mass Spectrometry Letters
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• 제7권1호
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• pp.26-29
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• 2016

Simultaneous determination of three corticosteroids (clobetasol propionate, betamethasone dipropionate, fluticasone propionate) in moisturizers was performed by using liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS). Sample preparation was conducted by the liquid-liquid extraction (LLE). Moisturizers include emulsifying agent and it forms micelles. In order to improve the extraction efficiency of corticosteroids trapped in micelle, newly developed-optimized extraction conditions which can remove the matrix effect from moisturizers was applied with various pH conditions in LLE extraction stage of sample preparation. Thus, the addition of 10 μL of 1 M HCl into moisturizers sample before extraction could improve the extraction efficiency. For the quantitative analysis, SRM table that contained specific transition of all of target corticosteroids was created. The developed method was validated for linearity, accuracy, precision, limit of detection (LOD), limit of quantization (LOQ) and recovery. Over the 0.99 r² value was obtained in calibration standard range. Effective accuracy and precision were also obtained. LODs were below 31 ng/mL and LOQs were estimated below 94 ng/mL for all corticosteroids tested.

• 청정기술
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• 제23권3호
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• pp.279-285
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• 2017

본 연구에서는 염화철 에칭폐액 재생을 위하여 (주)케이엠씨에서 조합한 organophosphorus acid계의 신규용매(KMC-P)를 사용하였으며, 용매추출공정에서 신규 용매에 대한 추출효율을 증가시키기 위해 공정변수를 선정하고 변수간의 상관관계를 알아보기 위해서 DOE에 따른 최적화실험을 진행하였다. 용매 농도, pH, O/A ratio가 추출, 탈거효율에 영향을 미치는 인자로 나타났으며 최적의 탈거효율을 갖는 공정조건은 용매 농도 29.4 wt%, HCl 첨가량 0 mL, O/A ratio 7일 때, 최대 69.7%의 탈거효율을 기대할 수 있는 결과를 얻었으며 신뢰 수준은 86% 이상인 것을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1780-1784
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• 2006

Cloud point extraction was used to extract mefenamic acid (MF) from human urine, and spectrofluorimetry and spectrophotometry were used to analyze extracted MF. The variables affecting extraction and phase separation, i.e. HCl and Triton X-114 concentration, temperature and time of equilibration, were optimized. Under the experimental conditions used the limit of detection for extraction of 25 mL of sample was 0.006 and 0.045 mg $L^{-1}$, with relative standard deviations of 2.52 and 1.45% (n = 5) for spectrofluorimetric or spectrophotometric methods, respectively. Good recoveries in the range of 95-107% were obtained for spiked samples. The proposed methods were applied to the determination of MF in human urine.

• 분석과학
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• 제12권5호
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• pp.370-374
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• 1999

추출 크로마토그래피를 이용하여 고순도 테르븀의 선택적 분리를 시도하였다. 고정상으로 2-ethylhexyl-2-ethylhexyl phosphonic acid(HEH[EHP]) 추출수지(-100~+150 mesh), 컬럼은 ${\Phi}20{\times}530mm$를 사용하고 온도는 $50^{\circ}C$로 유지하고, 흡착 유속은 $0.2mL/cm^2{\cdot}min$, 용출유속은 $1.0mL/cm^2{\cdot}min$, 컬럼의 높이와 직경의 비는 1:15로 하였다. 용리액의 산도, 시료의 부하량 및 시료의 조성을 변화시켜 테르븀의 분리의 최적조건을 설정하였다. 그 결과, 산도는 0.6 N HCl, 부하량은 약 5%, 시료의 조성은 $Gd_2O_3(20%)+Tb_4O_7(60%)+Dy_2O_3(20%)$이었다. 그리고, ICP-AES로 테르븀의 분리수율을 구한 결과 99.99% 이었고 순도는 99.98%이었다.

• 한국환경보건학회지
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• 제21권3호
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• pp.96-101
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• 1995

A selective and highly sensitive spectrophotometric measurements have been developed for the determination of trace mercury(II) with thiosulfate and PAR. Hg(II)-thiosulfate complex was extracted into high molecular alkylamine such as quaternary ammonium salt and back extracted into 1 M-HCl solution. The Hg(II)-PAR complex has maximum absorbance at 499 nm and obeys Beer's law in the range of 0.04~1.0 $\mu g/mL$ of mercury(II). The molar absorptivity and Sandell's sensitivity are $6.27\times 10^4 L.mole^{-1} cm^{-1}$ and $3.2\times 10^{-3}g/cm^2$ respectively.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1489-1494
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• 2004

A gas chromatography/mass spectrometric assay method was developed for the determination of persistent organochlorine pollutants (POPs) in hair. For the exact extraction study was used hair of rat exposed with POPs. Sonication of the hair matrix with 3 M HCl solution in methylene chloride of the extraction methods studied was the most efficient and rapid sample preparation method. After sonication of rat hair was achieved clean up with a solid phase extraction procedure using silica gel-florisil. Elution was performed with 8 mL of methylene chloride. The eluate was concentrated to approximately 100 ${\mu}L$ and analyzed by gas chromatography-mass spectrometry (GC-MS). Detection limits of POPs were in the concentration range of 0.6-1.2 ng/g in rat hair. Aldrin, dieldrin, p,p-DDT and mirex were dosed rat for 4 weeks at concentration of 0.01 mg/L in drinking water and detected in rat hair at concentration of 2.8, 11.3, 7.9 and 15.6 ng/g, respectively. Aldrin and p,p-DDT were metabolized to dieldrin and p,p-DDE, which were detected in concentration of 9.7 and 2.9 ng/g in rat hair, respectively. The developed method may be valuable to be used to analyze POPs in human hair.

• 한국축산식품학회지
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• 제34권6호
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• pp.749-756
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• 2014

A rapid and simple analytical method for L-carnitine was developed for infant and toddler formulas by liquid chromatography tandem mass spectrometry (LC-MS/MS). A 0.3 g of infant formula and toddler formula sample was mixed in a 50 mL conical tube with 9 mL water and 1 mL 0.1 M hydrochloric acid (HCl) to chemical extraction. Then, chloroform was used for removing a lipid fraction. After centrifuged, L-carnitine was separated and quantified using LC-MS/MS with electrospray ionization (ESI) mode. The precursor ion for L-carnitine was m/z 162, and product ions were m/z 103 (quantitative) and m/z 85 (qualitative), respectively. The results for spiked recovery test were in the range of 93.18-95.64% and the result for certified reference material (SRM 1849a) was within the range of the certificated values. This method could be implemented in many laboratories that require time and labor saving.

• 대한화학회지
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• 제41권8호
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• pp.392-398
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• 1997

무기수은과 유기수은을 분리하여 각각을 정량하는 방법을 연구하였다. 고분자량 알킬의 4차아민의 염, Aliquat 336의 $CHCl_3$ 용액을 이용하여 수용액 중에 함유된 무기수은이온, $Hg^{2+}$을 티오시안 착이온으로서, 그리고 유기수은 화합물, $CH_3HgCl$ 및 $C_2H_3O_2$ $HgC_6H_5$ 등을 동시에 추출농축한 다음 무기수은은 3 M $HClO_4 $ 용액으로 선택적인 역추출을 하여 CVAAS로 정량하고, 유기수은은 추출액의 $CHCl_3$ 을 증발 제거한 후 그 찌끼를 4% $KMnO_4 $-1M $H_2$$S0_4 $ 용액으로 분해하여 무기수은 이온으로 만들어서 역시 CVAAS로 정량하였다. 시료용액 50 mL 중에 함유된 Hg로서 1 ${\mu}g$의 무기수은과 유기수은 혼합용액(0.02 ${\mu}gHg/mL$)을 분석한 결과 절대오차 ${\pm}6%$ 이내의 결과를 얻었다.