• Analytical Science and Technology
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• v.27 no.4
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• pp.196-200
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• 2014

Currently nonaqueous titration method for the assay method using the hazardous reagent, mercury acetate for difemerine hydrochloride has been used in Korean Pharmaceutical Codex. We developed an alternative titration assay method by substituting the use of the hazardous reagent, mercury acetate to the use of less toxic ones like ethyl alcohol. The linearity of the calibration curves in the desired concentration range was good (r>0.999). Precision was less than 0.64%. Accuracy was obtained with recoveries in range of 99.10% and 99.71%. The developed assay could be expected to become valuable tools for revising the Korean Pharmaceutical Codex.

• Analytical Science and Technology
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• v.12 no.3
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• pp.243-247
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• 1999

After aconitine-type alkaloids have been isolated from the crude drug "Buza" as the precipitate, they could be identified with colour test, UV/Vis. absorption wavelength, TLC. The presence of aconitine-type alkaloids are confirmed by the reaction with the Reineke ion, $[Cr(NH_3)_2(SCN)_4]^{1+}$, and TCR ion, $[Co(SCN)4]^{2-}$, to produce the white precipitate or one of the containing from blue to yellowish blue. It is based on the formation of complex compounds by aconitine-type alkaloids with Reineke and TCR reagent. The method has been found to be simple, convenient and suitable for routine identification of aconitine-type alkaloids, related basic compounds, the crude drug "Buza" processed from the roots of certain Aconitum spp. plants(Ranunculaceae).

• Analytical Science and Technology
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• v.17 no.1
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• pp.23-28
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• 2004

Trace amount of uranyl (II) has been determined spectrophotometrically by measuring the optical density of the light blue yellowish coloured solutions formed by reaction between the metal ion and nicotinohydroxamic acid (NHx) in presence of different secondary ligands in strong isoamyl alcohol alkaline medium. The absorption maxima for both aqueous and extracted systems measured at their respective optimum pH were found to be 360 and 559 nm (DETA), 375 and 358 nm (EDA), 369 and 362 nm (piperidine), 354 and 341 nm (pyridine) and 363 and 336 nm (3 piperidine), 354 and 341 nm (pyridine) and 363 and 336 nm (3 - picoline), respectively at which Beer's law was obeyed. Effect of pH, reagent concentration, order of addition of reagent, time, temperature and solvent media on the absorption spectra have also been studied. Among the different systems studied, the shortest concentration range of uranyl(II) adhering to Beer's Law was 2.4 - 10.5 ppm observed for $UO_2(II)$ - NHx - DETA system in aqueous medium and also for iso amyl alcohol(IAA) extracted $UO_2$ - NHx - pyridine system was 2.4 - 7.8.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.331-338
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• 2007

A rapid, simple and sensitive spectrophotometric method was developed for the determination of cobalt(II) using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a analytical reagent. The metal ion in aqueous medium forms a brown coloured complex with HMBATSC at pH 6.0. The complex has two absorption maxima at 375 nm and 390 nm. At 375 nm, the reagent shows considerable absorbance, while at 390 nm the reagent does not shows appreciable absorbance. Hence, analytical studies were carried out at 390 nm. Beer's law is obeyed in the range of 0.059-2.357 μg ml-1 of Co(II). The molar absorptivity and Sandall's sensitivity of the method are 2.74×104 l mol-1 cm-1 and 0.0024 μg cm-2 respectively. The interference of various diverse ions has been studied. The complex has 1:2 [Co(II)- HMBATSC] stoichiometry. A method for the determination of cobalt(II) by second order derivative spectrophotometry has also been proposed. The proposed methods were applied for the determination of cobalt(II) in alloy steels, vitamin B12 and in some biological samples.

• Analytical Science and Technology
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• v.25 no.5
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• pp.284-291
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• 2012

Bloody fingerprint is a very important evidence. In this study, we confirmed the enhancement effects of ninhydrin, leucocrystal violet (LCV), fuchsin acid, iodine and dimethylaminocinnamaldehyde (DMAC) on bloody fingerprints which were deposited on paper. Bloody fingerprint were deposited on paper sequentially and used after drying at room temperature. If a ridge of bloody fingerprint was clear, ninhydrin and LCV was the most effective but was not good for invisible ridge. Fuchsin acid reagent dyed paper surface so that the contrast of enhanced bloody fingerprint was decreased. Although bloody fingerprint was enhanced with iodine reagent, but the developed color was very weak after reaction. We thought that the enhancement effect of iodine to bloody fingerprint was negligible. Also, the enhancement effect of DMAC reagent to relatively clear bloody fingerprint was not good. However, it was very effective to faint or invisible ridge. By washing with methanol, contrast of enhanced bloody fingerprint was increased.

• Analytical Science and Technology
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• v.36 no.3
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• pp.113-120
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• 2023

Physical developer (PD) is an effective technique that can develop fingerprints even on wet or very old paper. However, it has not been known which substance reacts with PD. Also, the timing of optimization according to the storage period of the PD working solution has not been known. The present research has done a spot test with 7 eccrine components and 5 sebaceous components that known as fingerprint components and figured out the mixture of palmitic acid and lysine gave the strongest positive reaction. Also, paper treated with PD was treated in 1,2-indanedione/zinc (1,2-IND/Zn) working solution and showed lysine was not dissolved in water. To find out the timing of optimization according to the storage period of the TWEEN^® 20 based PD working solution, the mixture of palmitic acid and lysine was used for the target of reagent reliability test. As the result, working solution of 14 days storage period showed better result than other working solutions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.458-461
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• 2003

Solid-phase microextraction (SPME) and gas chromatography/headspace techniques(HS) and flame ionization detection (GC/FID) have been combined for determination of very polar compounds in water, including the widely used gasoline oxygenates and by-products. A relatively simple extraction method using a CAR/PDMS(75${\mu}{\textrm}{m}$) SPME fiber was optimized for the routine analysis of gasoline oxygenates and by-products in groundwater and reagent water. A sodium chloride concentration of 25%(w/w) combined with an extraction time of 20 min provided the greatest sensitivity while maintaining analytical efficiency Replicate analyses in fortified reagent and groundwater spiked with microgram per liter concentrations of gasoline oxygenates and by-products indicate quantitative and reproducible recovery of these and related oxygenate compounds. Method dynamic range was 50$\mu\textrm{g}$ L-1 to 3000$\mu\textrm{g}$ L-1 for gasoline oxygenates and by-products.

• YAKHAK HOEJI
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• v.58 no.2
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• pp.125-128
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• 2014

We developed an alternative assay method without hazardous reagent of chloroform for urazamide tablets in Korean Pharmaceutical Codex. The HPLC analytical method was validated by system suitability, linearity, precision, accuracy and robustness. The linearity of the calibration curves in the desired concentration range is good ($r^2$ >0.999). Precision was obtained less than RSD 1.17%. Accuracy was obtained with recoveries in range of 98.12% and 99.47%. The developed assay could be expected to become valuable tools for revising the Korean Pharmaceutical Codex.

• Analytical Science and Technology
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• v.36 no.5
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• pp.250-257
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• 2023

The development of a spectrofluorimetric method for the determination of trimethoprim according to the reaction between O-phthalaldehyde (OPA) in highly alkaline media, and 2-mercaptoethanol (2ME) and this reaction gives fluorescent product measured at (458) nm when excited at (342) nm. The optimization of the analytical parameters that influence intensity was investigated. The intensity of fluorescence of the formed product was linearly related to the concentration of trimethoprim in the (100-1200) ng mL^-1 range. The limit of detection and limit of quantification were estimated to be (22.54) ng mL^-1 and (75.15) ng mL^-1 respectively. The utility of the proposed methods was successfully verified by analysis of trimethoprim in pure and real pharmaceutical preparations with high accuracy, the recovery percentages Re%, were found to be (100.5) % and (99.76) % for pure drug and pharmaceutical preparations respectively.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.81-86
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• 2015

A simple analytical method to quantify formaldehyde in water at lower levels (${\mu}g/L$) was developed using a high performance liquid chromatography (HPLC) and acetylacetone as a derivative reagent. Unlike conventional methods, no extraction and/or concentration were required. The derivative reagent was added into samples and reacted for 30 minutes at $80^{\circ}C$ prior to the analysis of formaldehyde using HPLC. The method detection limit and the limit of quantification for this method were 1.6 and $5.0{\mu}g/L$, respectively. This method also achieved high precision (0.6-3.0%) and accuracy (91.6-106.3%). The recovery rates for various environmental samples ranged from 92.0 to 115.2%.