• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.545-548
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• 2004

A sensitive, selective and rapid method for the determination of nickel based on the rapid reaction of nickel(II) with QADMAA and the solid phase extraction of the Ni(II)-QADMAA chelate with $C_{18}$ membrane disks has been developed. In the presence of pH 6.0 buffer solution and sodium dodecyl sulfonate (SDS) medium, QADMAA reacts with nickel to form a violet complex of a molar ratio of 1 : 2 (nickel to QADMAA). This chelate was enriched by solid phase extraction with $C_{18}$ membrane disks. An enrichment factor of 50 was obtained by elution of the chelates form the disks with the minimal amount of isopentyl alcohol. The molar absorptivity of the chelate was $1.32{\times}10^5L\;mol^{-1}cm^{- 1}$ at 590 nm in the measured solution. Beer's law was obeyed in the range of 0.01-0.6 ${\mu}$g/mL. This method was applied to the determination of nickel in water and biological samples with good results.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.263-266
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• 2004

A sensitive, selective and rapid method has been developed for the determination ${\mu}$g/L level of vanadium ion based on the rapid reaction of vanadium(V) with 2-(2-quinolylazo)-5-diethylaminophenol (QADEAP) and the solid phase extraction of the colored chelate with $C_{18}$ cartridge. The QADEAP reacts with V(V) in the presence of citric acid-sodium hydroxide buffer solution (pH = 3.5) and cetyl trimethylammonium bromide (CTMAB) medium to form a violet chelate of a molar ratio 1 : 2 (V(V) to QADEAP). This chelate was enriched by solid phase extraction with $C_{18}$cartridge and the enrichment factor of 50 was obtained by elution of the chelates from the cartridge with ethanol. The molar absorptivity of the chelate is $1.28 {\times}10^5L\;mol^{-1}cm^{-1}$ at 590 nm in the measured solution. Beer's law is obeyed in the range of 0.01-0.6 ${\mu}$g/mL. The detection limit is 0.04 ${\mu}$g/L in the original samples. This method was applied to the determination of vanadium(V) in water and biological samples with good results.

• The Plant Pathology Journal
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• 제15권1호
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• pp.34-37
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• 1999

Cymbidium mosaic virus (CyMV) was purified from CyMV infected orchid plant leaves by Sephacryl S-500 HR column chromatography. Partial purification was done by solubilization with Triton X-100 (alkylphenoxypolyethoxy ethanol) and precipitation with polyethylene glycol (PEG 6,000) followed by ultracentrifugation on 30% sucrose cushion. Based on the spectrophotometric analysis, 33 mg of CyMV could be obtained form 100 g of CyMV-infected orchid plant leaves. The purified CyMV represented one distinct homogeneous band by SDS-PAGE, and electron microscopy revealed that it was highly homogeneous and not fragmented. Bioassay demonstrated that the purified CyMV had a normal infectivity to Chenopodium amaranticolor and orchid plants. Based on these results, the purification method in this work could be served as an improved method for the purification of CyMV and similar viruses with good yield, high purity and native integrity.

• Applied Biological Chemistry
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• 제31권1호
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• pp.52-57
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• 1988

오이에서 얻어진 AAO조효소를 이용하여 AsA 정량 가능성을 검토할 결과, AAO에 의한 산화 전후의 흡광도 차는 AsA 함량과 정비례한 관계를 나타냈다. AAO를 이용한 AsA분석에 영향을 미치는 pH와 흡광도, 효소의 활성과 pH와의 관계, crude AAO의 pH 안정성, 효소의 농도와 반응시 간과의 관계를 검토한 결과, 흡광도 차가 최대를 나타낸 파장은 243nm였고, 효소의 활성이 최대를 보인 pH는 $pH\;6.0{\sim}7.5$범위였고, 본 실험에서 이용한 효소 농도로는 5분 이내에 산화반응이 종결되었다. 시판 오렌지쥬스의 AsA 함량을 AAO를 이용한 방법과 HPLC 방법에 의해서 분석하여 비교한 결과, 본 방법으로 분석된 AsA함량과 HPLC방법에 의해서 얻어진 수치는 거의 비슷한 값을 나타냈으며, 본 방법에 의한 AsA회수율은 $98.3{\sim}99.8%$로 높은 검출효과를 보였다.

• 대한화학회지
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• 제19권4호
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• pp.246-251
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• 1975

Dideptidyl carboxypeptidases와 angiotenisn-coverting enzyme의 새로운 기질불질로서 thiol ester 인 S-Hippuryl thioglycolyl glycine을 합성하였으며, 이 기질에 의한 간편하고도 예민한 효소 활성도의 정량방법을 제시하였다. 이 경우 효소반응 생성물인 thioglycolyl glycine은 반응계중에 첨가한 5,5-dithio-bis-(2-nitrobenzoic acid), DTNB와 쉽게 반응하여 410nm에서 강한 흡광스펙트럼을 갖는 5-thio-2-nitrobenzoic acid(${\varepsilon}M=1.36{\times}10^4$)을 형성함으로서 효소의 새로운 미량정량 방법으로 이용 가치가 크다고 본다.

• Animal cells and systems
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• 제11권2호
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• pp.161-164
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• 2007

Oxidative stress is prerequisite for the development of atherosclerosis. Apart from the traditional risk factors that contribute to this devastating condition, in the past few decades, much attention has been focused on plasma total homocysteine mainly because of its strong association with coronary artery disease. It has been suggested that homocysteine induces oxidative stress and hence the present work was undertaken to assess the total homocysteine status and plasma total antioxidant capacity in the acute myocardial infarction (AMI) patients among Tamil population. The study subjects included only the Tamil population. Blood samples were collected from 100 AMI patients and 100 controls. Plasma was separated and the total antioxidant status was assessed as a measure of ferric reducing power of antioxidants using spectrophotometric method. Plasma total homocysteine concentrations were assessed by automated chemiluminescence method. While Total antioxidant status was significantly decreased, the plasma homocysteine concentrations were elevated in AMI patients compared to the controls. However, there was no correlation between the homocysteine levels and total antioxidant status. The findings of this study may have therapeutic implications, including food sources rich in antioxidants for all AMI patients to minimize the effect of free radicals formed during oxidative stress among Tamil population.

• 대한화학회지
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• 제59권5호
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• pp.407-412
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• 2015

A preconcentration procedure for determination of palladium by laser thermal lens spectrometry (TLS) is proposed. It is based on cloud point extraction of palladium(II) ions as 2-(3,5-dichloro-2-pyridylazo)-5-dimethylaminoaniline (3,5-diCl-PADMA) complexes using octylphenoxypolyethoxyethanol (Triton X-114) as surfactant. The effects of various experimental conditions such as pH, concentration of ligand and surfactant, equilibration temperature and time on cloud point extraction were studied. Under the optimized conditions, the calibration graph was linear in the range of 0.15~6 ng mL⁻¹, and the detection limit was 0.04 ng mL⁻¹ with an enrichment factor of 22. The sensitivity was enhanced by 846 times when compared with the conventional spectrophotometric method. The recovery of palladium was in the range of 96.6%~104.0%. The proposed method was applied to the determination of palladium in water samples.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3437-3442
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• 2011

An on-line flow injection analysis with dual pre-concentration method was developed to determine the ultra trace tri and hexavalent chromium in water. In this system, the cation and anion pre-concentration columns were combined with a 10-port injection valve and then used to separate and concentrate Cr (III) and Cr (VI) selectively. The two species of concentrated chromium were sequentially eluted and determined by using HCl-KCl buffer of pH 1.8 as an eluent. Cr (III) was oxidized by hydrogen peroxide to Cr (VI). It was detected spectrophotometrically at 548 nm by complexation with DPC (diphenylcarbazide). Several factors such as concentration of $H_2O_2$, DPC and coil length in reaction condition were optimized. The linear range for Cr (III) and Cr (VI) was 0.1-50 ${\mu}g$/L. The limit of detections ($3{\sigma}$) of Cr (III) and Cr (VI) were 52 ng/L and 44 ng/L under the optimized FIA system, and their recoveries 98% and 103%, respectively. This method was applied to analyze contamination level of chromium species in tap water, groundwater and bottled water.

• Archives of Pharmacal Research
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• 제12권3호
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• pp.160-165
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• 1989

Binding of sulfaethidole to bovine serum albumin was studied by equilibrium dialysis, fluorescence probe technique, uv difference spectrophotometry and circular dichroism. Equilibrium dialysis method enabled us to estimate the total number of drug binding sites of albumin molecule. For sulfaethidole, albumin had 6 primary and 40 secondary binding sites. The primary and secondary binding constants were 0.9 * 10/sup 5/ M/sup -1/ and 0.2 * 10/sup 6/ M/sup -1/, respectivitely. 1-Anilino-8-naphthalenesulfonate (ANS) and 2-(4-hydroxylbenzeneazo)- benzoic acid (HBAB) were used as the fluorescence probe and the uv spectrophotometric probe, respectively. In fluorescence probe technique, results indicated that the number of higher affinity drug binding site of albumin was 1 and the number of lower affinity drug binding sites of albumin was 3, and the primary and secondary drug binding constants for bovine serum albumin were 2.15 * 10/sup 5/M/sup -1/ and 1.04 * 10/sup 5/ M/sup -1/, respectively. In uv difference spectrophotometry, binding sites were 3 and binding constant was 1.88 * 10/sup 5/M/sup -1/. The above spectrophotometry, binding sites were 3 and binding constant was 1.88 * 10/sup 5/M/sup -1/. The above results suggest that several different methods should be used in ompensation for insufficient information about drug binding to albumin molecule given by only one method.

• 한국연초학회지
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• 제2권2호
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• pp.14-19
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• 1980

바르비트릭산 완충용액을 반응시약으로 사용하여 잎담배중의 니코틴을 정량하였다. 니코틴과 바르비트락산 완충용액이 반응하여 생성 된 생성물의 분간 홉수 분광도의 값은 안정하였다. 홉수 극대파장은 505nm였으며 pH4.2에서 15분간 흡수 분광도의 값은 안전하였다. 흡수 분광도 값은 니코틴 농도$7.5\mu{g}/ml$부터 $25\mu{g}/ml$까지는 Laulbert-Beer의 법칙을 잘 따라 주었다. 잎담배에 대해서 Griffith방법과 이 방법에 따라 분석한 결과 Griffith방법에 대하여 최대편차2.1% 범위에서 두 값은 일치 하였으며 자동 분석기에 의한 분석결과는 두 값의 최대펀차2.8%내에서 일치하였다.