• Analytical Science and Technology
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• v.28 no.4
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• pp.255-259
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• 2015

A technique on the determination of Co(II) in aqueous samples with quinalizarin-β-cyclodextrin inclusion complex was developed. The conditions such as pH of the sample solution, the concentration of quinalizarin and the concentration of β-CD were optimized to 11.3(±0.2), 1.2×10⁻⁶ M and 8.0×10⁻⁶ M, respectively. Under these optimum conditions, the calibration curve of Co(II) was obtained over concentration range of 5.0×10⁻⁹ ~ 1.2×10⁻⁷ M. The detection limit was 4.2×10⁻⁹ M (0.25 ng/mL). For validating this proposed technique, aqueous samples(stream water, reservoir water and tap water) were used. Recovery yields of 95~105% were obtained. The relative standard deviation(%) in aqueous samples were less than 7.0%. Based on experimental results, it is proposed that this technique can be applied to the practical determination of Co(II).

• Journal of the Korean Chemical Society
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• v.46 no.4
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• pp.309-317
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• 2002

A spectrofluorimetric method for the simultaneous determination of amino acids (tryptophan and tyrosine) based on the application of multivariate calibration method such as principal component regression and partial least squares (PLS) to luminescence measurements has been studied. Emission spectra of synthetic mixtures of two amino acids were obtained at excitation wavelength of 257 ㎚. The calibration model in PCR and PLS was obtained from the spectral data in the range of 280-500 ㎚ for each standard of a calibration set of 32 standards, each containing different amounts of two amino acids. The relative standard error of prediction ($RSEP_a$) was obtained to assess the model goodness in quantifying each analyte in a validation set. The overall relative standard error of prediction ($RSEP_m$) for the mixture obtained from the results of a validation set, formed by 6 independent mixtures was also used to validate the present method.

• Journal of the Korean Chemical Society
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• v.46 no.5
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• pp.407-411
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• 2002

A method to determine lead ion in aqueous media using an optical sensor loaded on a fluorescent optode membrane incoporating a metal ion-selective ionophore, a proton-selective chromoionophore and lipophilic anionic sites has been studied. The effects of pH and thickness of membrane on the fluorescence intensity were investigated. The effects of foreign ions such as $Na^+$, $K^+$, $Mn^{2+}$ and $Zn^{2+}$ on the determination of lead ion were also studied. The linear range in the calibration curve for the determination of lead ion was found to be 5.0${\times}10^-7$ to 5.0${\times}$$10^-3$M and the correlation coefficient in this range was -0.99107 under the optimal experimental conditions. The relative standard deviation of the blank signals was 3.0% and the detection limit of lead ion was 5.0${\times}$$10^-9$M.

• Analytical Science and Technology
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• v.17 no.1
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• pp.45-52
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• 2004

Determination of some PAHs in sediments at Ulsan bay has been carried out by extraction of the components into n-hexane followed by synchronous spectrofluorimetric technique. 11 PAHs, such as acenaphthene (Ace), anthracene (Anth), benz(a)anthracene (BaA), benzo(b)fluoranthene (BbFt), benzo(k)fluoranthene (BkFt) benzo(a)pyrene (BaP), chrysene (Chry), phenanthrene (Phen), fluoranthene(Ft), perlyrene (Per), and pyrene (Pyr) in sediment samples were able to determine separately by synchronous spectrofluorimetry. Calibration curves for those components were linear for the concentration range of 0.15~166 ppb PAHs with the correlation factor of 0.9985~0.9999. The total amount of PAHs in sediments varied from 68.8 to 324.4 ng/g. The PAHs concentration was shown a tendency to increase from the outer bay to the inner basin as well the predominant contributors to the aromatic ring groups of the PAHs was 4-ring group.

• Analytical Science and Technology
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• v.22 no.4
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• pp.307-312
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• 2009

A spectrofluorimetric methods has been developed for the determination of carbaryl in an aqueous solution. The effects of excitation wavelength, concentration of surfactant, concentration of ethanol as cosurfactant and emission wavelength on the fluorescence intensity were investigated to find the optimum experimental conditions to determine carbaryl. The emission intensity of the carbayl was increased with addition of sodium dodecyl sulfate (SDS) as a surfactant. The emission intensity of the carbaryl was further increased with addition of ethanol as a co-surfactant. The optimum conditions were 281 nm for excitation wavelength, $1.0{\times}10^{-2}mol/L$ SDS, 20% (v/v) ethanol and 349 nm for emission wavelength. Under the optimum conditions, the emission intensity increased with the carbaryl concentration in the range of $5{\times}10^{-7}$ to $1.0{\times}10^{-4}mol/L$ with a detection limit ($3{\sigma}$) of $1.1{\times}10^{-8}mol/L$. The resulting correlation coefficient of the working curve was 0.9996.

• Analytical Science and Technology
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• v.16 no.5
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• pp.339-348
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• 2003

Determination of some PAHs in used engine oils have been carried out by extraction of the components into acetonitrile followed by GC/FID and synchronous spectrofluorimetric technique. 7 PAHs, such as acenaphthene (Ace), anthracene (Anth), benzo(a)pyrene (BaP), chrysene (Chry), phenanthrene (Phen), fluoranthene (Ft), and perlyrene (Per) in used engine oil sample were able to determine separately by synchronous spectrofluorimetry. Calibration curves for those components were linear for the concentration range of 0.4~166 ppb PAHs with the corelation factor of 0.9985~0.9999. The peak areas produced by GC/FID split ratio program were used for the calibration curves of the other 8 PAHs. Detection sensitivity of the synchronous spectrofluorimetry seems to be 100 times more sensitive than GC/FID method. The total amount of PAHs in the used engine oil were 5.5 ng/g for LNG (bus), 10.5 ng/g for LPG(taxi), 92.2 ng/g for gasoline-passenger car, and 130 ng/g for diesel trailer, respectively.