• Analytical Science and Technology
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• v.8 no.4
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• pp.469-475
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• 1995

Di-2-pyridylmethanon 2-thiophenecarboxylie hydrazone(DPMTCH) was synthesized and used as a chromogenic reagent in the spectrophotometric determination of nickel in steel. The proton disc spectrophotometrically, were $pK_{a1}= 2.66$ and $pK_{a2}= 10.98$ ${\mu}=0.5(NaCl)$. Nickel(II) reacts with DPMTCH to form a 1:2 metal-2-ligand ratio complex, the xylene solution of which has an absorption maximum at 417 nm. Beer's law is obeyed over the range $0-1.17\;mg\;ml^{-1}$ of nickel(II). The molar absorptivity of the nickel(II) complex is $4.17{\times}10^4l\;mol^{-1}\;cm^{-1}$. The precision of the method was estimated for 4.7 mg of nickel(II), the coefficient of variation for 15 replicate determinations being 0.34%.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.360-363
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• 1994

A colorimetric assay for $\gamma$-glutamyl transpeptidase ($\gamma$-CTP; E.C 2.3.2.2) employing 2, 4, 6-trinitrobenzene sulfonate (TNBS) to detect the amount of disappeared acceptor via transpeptidation, has been developed. Under the experimental conditions using L-$\gamma$-glutamyl ethyl ester and L-phenylalanine as $\gamma$-glutamyl donor and acceptor, respectively, it was found that the decreased absorbance of yellow color at 420 nm was strictly related to the amount of L-$\gamma$-glutamyl-L-phenylalanine (L-$\gamma$-Glu-L-Phe) formed, which was determined by DEAE-cellu-lose column chromatography. Concentrations of the enzyme and $\gamma$-glutamyl products were able to be determinedin the nanogram and nanomoles per milliliter range, respectively, with high precision and reliability. This novel assay system may therefore be a useful means for understanding of catalytic function of the $\gamma$-CTP spectrophotometrically without any usage of sophisticated instruments.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3377-3380
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• 2013

The spectrophotometric and electrochemical properties of tetraazo(p-carboxy)phenylcalix[4]arene (p-CAC) in the presence of various metal ions were investigated by UV/Vis spectroscopy and voltammetry in $CH_3CN$. p-CAC showed selective color changes to $Cu^{2+}$ over other metal ions from light orange to colorless, in accordance with hypsochromic shift in UV/Vis spectra. Voltammetric measurements also showed high selectivity for $Cu^{2+}$.

• YAKHAK HOEJI
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• v.46 no.4
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• pp.226-230
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• 2002

The Coptis Rhizome is known for containing a number of isoquinoline type alkaloids. Berberine, coptisine and palmatine are the major constituents of alkaloids. The alkaloids were isolated and determined by forming complex from Coptis japonica (Ranunculaceae). For the determination of these alkaloids, a new spectrophotometric method was developed with a simple and selective sample clean-up using thiocyanatocobaltate[II] complex ion. The absorbance of alkaloidal complex in l,2-dichloroethane solution was measured at 625 nm. A calibration curve for the alkaloids isolated from Coptis Rhizome was linear over the concentration range of 0.2-0.3 mg/mι. The method proved to be rapid, simple and reliable for the isolation and the determination of the alkaloids in Coptis Rhizome.

• Journal of the Korean Chemical Society
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• v.10 no.1
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• pp.4-10
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• 1966

A new method of cobalt determination has been developed by employing ethylenediamine tetrabutyl acetate(EDTA-butyl ester) synthesized from EDTA and Butyl alcohol. The synthesized EDTA ester dissolved in butyl alcohol extracts various metal ions from aqueous solutions. Cobaltous ion extracted into organic phase containing EDTA ester to form Co (II)-EDTA butyl ester complex is back extracted into alkaline aqueous phase forming a stable pink colored complex of Co (III). The optimum condition for spectrophotometric determination of cobalt via the new complex has been established. The absorption peak occurs at 540$m{\mu}$ and Beer's law was obeyed over the concentration range of 0∼50 ${\mu}g/ml$ of cobalt.

• Journal of the Korean Chemical Society
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• v.6 no.1
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• pp.69-72
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• 1962

Spectrophotometric studies have been made on the solutions of elementary iodine in pyridine and quinoline, in the absence of light. The results shown that triiodide ion is produced in both solutions with different rates, and that triiodide ion behaves differently in both solutions. Iodine reacts slowly with pyridine, giving rise to triiodide ion, which is relatively stable in this solvent, hereas, iodine reacts rapidly with quinoline, forming triiodide ion, which interacts further with the medium at slow rate. It has been thought that the difference of the behavior of triiodide ion in both solutions may be due to the stronger basicity of quinoline than pyridine.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1261-1264
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• 2003

A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and $25{\circ}C$ is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples.

• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1767-1770
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• 2003

A simple, rapid and sensitive spectrophotometric method is herewith proposed for the determination of copper(II) by using diamine-dioxime ligand, meso-3,6,6,9-tetramethyl-4,8-diazaundecane-2,10-dione dioxime or meso-HexaMethyl Propylene Amine Oxime (meso-HMPAO). This method is based on the formation of a stable 1 : 1 red-pink complex between copper(II) and meso-HMPAO in aqueous solution. Absorption measurements were carried at 497 nm, with a molar absorptivity value of 338 L $mol^{-1}\;cm^{-1}$. Beer's law was obeyed over the concentration range of 0.5-370 ${\mu}$g $mL^{-1}$ with a Sandell's sensitivity value of 0.18 ${\mu}$g $cm^{-2}$. The proposed method has been successfully applied for determination of copper(II) in foodstuffs and pharmaceutical samples. The results obtained from this method are comparable with those obtained AAS.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1535-1542
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• 2010

Spectrophotometric micro determination of allopurinol (ALP) via charge-transfer formation is described. This includes the utility of some $\pi$-acceptors such as 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 3,6-dichloro-2,5-dihydroxy-p-benzoquinone (p-CLA) for estimation of ALP drug (act as $\grave{e}$-donor). These reactions are applied for determination of ALP in its pharmaceutical preparations coming from different companies. Elucidation of the chemical structure of the solid CT complexes formed via reaction between drugs under study and $\pi$-acceptors, using elemental analyses (C, H, N), I. R., $^1H$ NMR and mass spectrometry.

• Journal of the Korean Chemical Society
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• v.15 no.1
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• pp.5-9
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• 1971

A separation scheme using cation exchange procedure is designed specifically for the rapid determination of thorium in monazite samples. All the coexisting ions in monazite, including rare earth ions, are eluted with 3N hydrochloric acid. The remaining thorium is eluted from the resin column with 5N sulfuric acid prior to spectrophotometric determination with thorin reagent. The radioactive tracers and spectrophotometric methods were used to confirm the quantitative elution of thorium and also the chemical purity of the eluted thorium from the column.