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

• Archives of Pharmacal Research
• /
• v.17 no.6
• /
• pp.415-419
• /
• 1994

A simple nad rapid colorimetric method for the assay of amodiaquine hydrochloride, chloroquine phosphate and primaquine phosphate is described. The method is based on the interaction of the drug base with bromophenol blue to give a ion-pair complex. The spectra of the complex shows a maxima at 415-420 nm with high apparent molar absorptivities. Beer's law was obeyed in the concentration range 1-8, 2-10 and $2-12{\;}{\mu}{\cdot}ml^{-1}$ for amodiaquine hydrochloride, primaquine phosphate and chloroquine phosphate respectively. The proposed method was applied to the determination of these drugs in certain formulations and the results were favourably comparable to the official methods.

• Journal of the Korean Chemical Society
• /
• v.10 no.1
• /
• pp.4-10
• /
• 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 Environmental Science International
• /
• v.4 no.1
• /
• pp.13-18
• /
• 1995

In order to examine the effect on the insolation of cloud cover, we analyzed the data of the insolation, cloud cover and surface air pressure in Pusan during the period of 1991. 10 - 1993.1. At first, we investigate the atmospheric transmissivity A(t) using the Beer's law at clear skies. The atmospheric transmissivity is characterized by cold season high and warn season low. From this atmospheric transmissivity, the empirical formula that shows the variation of the insolation due to the cloud cover is obtained. The result formula is I : l0 A(tn)·( 0.7-0.05×m ). 1 is the insolation that reaches the surface when cloud cover is m and to is solar constant. Although the result is some rough it seems meaningful that the estimation of insolation can be made only from the routine data.

• Bulletin of the Korean Space Science Society
• /
• 1993.10a
• /
• pp.11-11
• /
• 1993

The Korean sounding rockets(KSR) 1, 2 equigped with the UV optical detectors have been launched at An-heung, Chungchongnam-do, of June 4 and September 1, 1993,respectively. The UV detector is used to measure the attenuation of solar UV radiation for various frequency bards in the stratospgere. We obtained the profile of the ozone number density within the altitulde of 15 - 30 km by applying the Beer-Lambert law. It is found that the maHimum of the ozone distribution occurs near 2sht which is quite consistent with the mean value in the mid-latituderegions. We will also compare our results froiu KSR 1,2 with the other observational data from the Dobson speceo meter at Yonsei Univ. and the LIDAa which were performed simultaneously with the sounding rocket experiments.

• YAKHAK HOEJI
• /
• v.13 no.2_3
• /
• pp.51-56
• /
• 1969

In quantitative analysis of sulfonamide drugs by means of infrared Spectrophotometry, the author tried to analyse Sulfamethoxydiazine and Sulfamethoxypyridazine in their Pharmaceutical Preparations. By the survey of infrared absorption spectra of Sulfamethoxydiazine and Sulfamethoxypyridazine. We found quantitative properties at the peaks of wave number 1150 cm$^{-1}$ (Sulfamethoxydiazine) and 1090 cm$^{-1}$ (Sulfamethoxypyridazine) in the spectra. These peaks obey Beer's Law in a range of 50-150 ug for Sulfamethoxydiazine and 70-350 ${\mu}$g for Sulfamethoxypyridazine in 300 mg KBr disc. By this method, Sulfamethoxydiazine and Sulfamethoxypyridazine could be analyzed less than 2% error.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.3
• /
• pp.373-378
• /
• 2007

A micro organism Agrobacterium tumifacient as an immobilized cell on a solid support was presented as a new biosorbent in a simple and sensitive spectrophotometry determination of Ni(II) in various samples using 4-hydroxy benzaldehyde-4-bromophenyl hydrazone as a color developing agent (λmax 497 nm) at pH 4.0 ± 0.2. Beer's law was obeyed over the range of 0.01-0.1 μg L-1. The molar absorptivity and Sandell's sensitivity were 1.285 × 105 L mol-1cm-1 and 0.007245 μg cm-2 respectively. Under these conditions, the preconcentration factor obtained was 82, and the detection limit achieved was 0.05 μg L-1. The detailed study of various interfering ions made the method more sensitive and selective. The recovery of Ni(II) from various samples range from 97.75 to 99.35%. The present method was successfully applied for the determination of Ni(II) in spiked, natural water and alloy samples. The proposed method was compared with reported methods in terms of Student's ‘t'-test and Variance ratio ‘f'-test which indicates that there is no significant difference between proposed and literature method at 95% confidence level.

• Journal of the Korean Chemical Society
• /
• v.37 no.5
• /
• pp.496-502
• /
• 1993

Spectrophotometric determination of rare earth elements with MTB and the composition ratio were investigated in the presence of surfactants of cetylpyridinium chloride (CPC), Triton X-100, dodecyltrimethylammonium bromide (DTMAB) and cetyltrimethylammonium bromide (CTMAB) at pH 6.5. The colour development between MTB and rare earths in the presence of cationic surfactants was very stable and more sensitive than that in the absence of surfactants. The largest absorbance increase was provided by CPC, which was therefore chosen for determination of rare earth elements. REE-MTB-CPC complex has absorption maxima at 650 nm and obeys the Beer's law in the range of 0∼100 ng/ml. Molar absorptivity is $6.6{\sim}9.4{\times}10^4\;mol^{-1}l\;cm^{-1}$.

• Journal of the Korean Chemical Society
• /
• v.44 no.4
• /
• pp.322-327
• /
• 2000

A new absorption spectrometric method for the determination of the Cr$_2O_7^{2-}$ ionin acidic media has been developed. The new method is based on the oxidation-reduction reaction of the HCr$O_4^-$ ion with H$_2$O$_2$forming a deep blue CrO(O$_2$) $_2$ andis coupled with a technique of flow injection analysis(FIA). The new method provides a linear calibration curve which accurately follows the Beer's law over a wide range of the analytical concentrations(2.0 ${\times}$ $10^{-6}$M~8.0 ${\times}$ $10^{-3}$M) of K$_2$Cr$_2$O$_2$. The sensitivity of the new method is approximately two times greater than the current method and the effects of the interfering substances such as V, Co, Ni, Fe, and Mn are almost negligible except Cu.

• Analytical Science and Technology
• /
• v.7 no.3
• /
• pp.277-284
• /
• 1994

The spectrophotometric determination of rare earth elements with XO was investigated in the presence of cetylpyridium chloride(CPC), dodecyltrimethylammonium bromide(DTMAB), cetyltrimetylammonium bromide (CTMAB), Triton X-100 at pH 6.2. The complex between XO and rare earth elements in the presence of cationic surfactants was very stable and more sensitive than in the absence of surfactants. The largest absorbance increase was provided by CTMAB, which was therefore chosen for determination of rare earth elements. REE-XO-CTMAB complex has absorption maxima at 618nm and obeys the Beer's law in the range of 0~0.5 ppm. Molar absorptivity was $1.5{\times}10^5mol^{-1}cm^{-1}l$.