• Journal of the Korean Chemical Society
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• v.38 no.1
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• pp.50-54
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• 1994

Spectrophotometric determination of some light lanthanide ions by flow injection method is described. Chromeazurol S forms water soluble complex with lanthanide ions in the presence of DTAB. The absorption maximum of the complexes are from 650 nm to 655 nm and the molar absorptivities were ca. $1.8{\times}10^5\;L mol^{-1}cm^{-1}$ on Tris buffer (pH 10.5). The calibration curves for Nd(III), Eu(III) and Sm(III) obtained by FIA are over the range of 0.1 to 0.6 ppm and the correlation coefficient were ca. 0.9993. The detection limits (S/N) were from 10 ppb for Nd(III) and Eu(III) to 20 ppb for Sm(III). The relative standard deviations was ${\pm}$.2% for 0.4 ppm sample. The samples throughput was ca. $50\;cm^{-1}$.

• Journal of the Korean Chemical Society
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• v.47 no.1
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• pp.19-25
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• 2003

A spectrophotometric method for the simultaneous determination of anionic and nonionic surfactant based on the application of multivariate calibration method such as principal component regression(PCR) and partial least squares(PLS) has been studied. The calibration models in PCR and PLS were obtained from the spectral data in the range of 400~700 nm for each standard of a calibration set of 26 standards, each containing different amounts of two surfactants. The relative standard error of prediction(RSEP$_{\alpha}$) was obtained to assess the model goodness in quantifying each analyte in a 5 validation samples which containing different amounts of two surfactants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.95-100
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• 2006

Sesamin and sesamolin, antioxidant lipidsoluble lignan compounds, are abundant in sesame (Sesamum indicum L.) seed oil and provide oxidative stability of oil related to sesame quality. The sesamin and sesamolin contents of 403 sesame land races of Korea were determined by HPLC analysis of methanol extract (HPLC value), and their total lignan content was compared with those by using UV-Vis spectrophotometric analysis (UV method) of methanol (UV-MeOH value) and hexane (UV-Hexane value) extracts. HPLC values of total lignan content were strongly associated with UV-Hexane (r=0.705**) and UV-MeOH (r=0.811**) values. The UV values from both the extracts were 3.8-4.7 times higher than those of HPLC values. Lignan content was overestimated by UV method because total compounds in the mixture solution were quantified by absorbing at the same ultraviolet wavelength as in HPLC method. UV method could more rapidly analyze small amount of sample with higher sensitivity of detection than HPLC method. Average contents of lignans in sesame germplasm evaluated in this study were $2.09{\pm}1.02mg/g$ of sesamin, and $1.65{\pm}0.61mg/g$ of sesamolin, respectively, showing significant variation for lignan components. The results showed that UV method for the determination of sesamin and sesamolin could be practically used as a faster and easier method than HPLC by using the regression equations developed in this study.

• Journal of the Korean Chemical Society
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• v.36 no.4
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• pp.546-551
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• 1992

Reaction mechanism on the solvent extraction of nickel(Ⅱ) with N-benzylisonitrosoacetylacetone imine(HIAANB) was studied spectrophotometrically. Absorbance was measured by changing the ligand HIAANB concentration in the chloroform organic phase and the pH values in the agueous solution phase. From the absorbance data, the reaction rate was found to be the first order for HIAANB concentration and the inverse first one for [$H^+$]. The rate determining step of the extraction reaction and the rate equation are as follows; $Ni^{2+}$＋HIAANB ${\to}$ Ni-IAANB$^+$＋$H^+$ -d[Ni$^{2+}$] / dt = K'[Ni$^{2+}$][HIAANB]$_0$ / [H$^+$] Calibration curve for the spectrophotometric determination of nickel(Ⅱ) ion in the aqueous solution was linear below the concentration of 1.17 ppm at the optimum experimental condition. And the ligand-to-metal ratio, the relationship between extractability and pH of the aqueous phase, and the effect of diverse ion on the determination of nickel(Ⅱ) ion were examined.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.725-732
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• 2006

A rapid flotation methodology for zinc(II) separation and enrichment from human biofluids is established. At pH 6.0 and ambient temperature, using oleic acid (HOL) as a foaming reagent, zinc(II) was separated with phenanthraquinone monophenyl thiosemicarbazone (PPT) as a new flotation collector for Zn(II). The floated red colored 1 : 2 Zn(II)-PPT complex was measured spectrophotometrically at 526 nm with a molar absorptivity of $1.83 \;{\times}\; 10^5\; L$ mol $L ^{-1}\;cm ^{-1}$. Beer's law was obeyed over a concentration range 0.05-1.0 mg $L ^{-1}$ in the aqueous as well as in the scum layers. The proposed preconcentration flotation methodology was applied to determine Zn(II) in human biofluids. Application was, also, extended to determine Zn(II) in pharmaceutical samples and natural water samples spiked with known amounts of Zn(II) with a preconcentration factor of 100 and a detection limit of 10 ng m$L ^{-1}$. The method was verified by comparison of the spectrophotometric results with flame atomic absorption spectrometric (AAS) measurements. Moreover a postulation for the mechanism of flotation is proposed.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.291-293
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• 2010

알카리성 과황산칼륨을 이용한 자외선 흡광광도법은 수중의 총질소를 간편하면서도 신속하고 정확하게 분석할 수 있는 방법으로 각각의 질소성분을 standard method에 의해 분석한 후 이들을 합산하는 방법보다 회수율이 좋게 나타났다. 자외선 흡광광도법을 이용할 경우 Cr(VI)이온과 Br이온에 의해 방해를 받으므로, Br이온을 다량 함유하는 해수의 총질소 분석방법으로는 적합하지 않은 것으로 관찰되었다. 전처리를 한 후 220 nm에서 흡광도를 측정하기 위해서는 탄산염의 방해를 방지하기 위해 pH를 2~3으로 조절한 후 분석해야만 하고, 알카리성 과황산칼륨을 이용한 자외선 흡광광도법은 총질소를 분석하는 방법으로 우수성이 입증되었으나 각 형태별 질소의 농도를 측정할 수 없는 단점이 있으므로 각 형태별 질소의 농도를 측정하기 위해서는 standard method를 이용해야 된다. 본 연구에서 알카리성 과황산칼륨을 이용한 자외선 흡광광도법은 총질소를 분석하는데 있어서 standard method에 의한 합산법보다 시간과 노력을 절약할 수 있는 것으로 검토되었다.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.858-861
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• 2001

Near Infrared spectroscopy was applied to the samples of processed pork to see the effect of grinding on chemical components analyses. Data from conventional chemical analyses of moisture, fat, protein, NaCl were put into calibration model by NIR of reflectance mode. The other properties observed were pH and color parameters ($L^*,\;a^*,\;b^*$). Spectral ranges of 400~2500 nm and 400~1100 nm were compared for color parameters. Spectral ranges of 400~2500 nm and 1100~2500 nm were compared for chemical components and pH. Different spectral ranges caused little changes in the coefficients of determination or standard errors. $R^{2,}s$ of calibration models for color parameters were in the range of 0.97 to 1.00. $R^{2,}s$ of calibration models of intact sausages for moisture, protein, fat, NaCl and pH were 0.98, 0.89, 0.95, 0.73 and 0.77, respectively using spectra at 1100~2500 nm. $R^{2,}s$ of calibration models of ground sausages for moisture, protein, fat, NaCl and pH were 0.97, 0.91, 0.97, 0.42 and 0.56, respectively using spectra at 1100~2500 nm.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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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.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2732-2736
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• 2011

In pH 4.2 HAc-NaAc buffer solution, horseradish peroxidase (HRP) catalyzed $H_2O_2$ oxidation of nanosilver to form $Ag^+$. After centrifugation, $Ag^+$ in the supernatant can be measured by graphite furnace atomic absorption spectrophotometry (GFAAS) at the silver absorption wavelength of 328.1 nm. When HRP concentration increased, the $Ag^+$ concentration in the supernatant increased, and the absorption value enhanced. The HRP concentration in the range of 0.84-50 $ng{\cdot}mL^{-1}$ was linear to the enhanced absorption value (${\Delta}A$), with a regression equation of ${\Delta}A$=0.012C+0.11, correlation coefficient of 0.9988, and detection limit of 0.41 $ng{\cdot}mL^{-1}$ HRP. The proposed GFAAS method was used to detect HRP in waste water samples, with satisfactory results.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.452-456
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• 1987

Acidic strength of benzenesulfonic acid (HBs) and it's derivatives, p-toluenesulfonic acid(HTs), p-chlorobenzenesulfonic acid(HCs) and m-nitrobenzenesulfonic acid(HNs), were measured in the anhydrous acetic acid medium by spectrophotometry. p-naphtholbenzein (PNB) was used as an indicator base and the ionization constants of HTs, HBs, HCs and HNs were $3.5{\times}10^2,\;4.1{\times}10^2,\;19.3{\times}10^2\;and\;50{\times}10^2$, respectively, at 20.0${\pm}$0.1$^{\circ}$C.