• 분석과학
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• 제8권4호
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• pp.787-792
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• 1995

A method for determination of ammonia-N in environmental water by air-segmented flow injection analysis using the colour reaction of phenol and sodium hypochlorite with ammonia was described in this paper. When the reaction temperature is $70^{\circ}C$ and the reaction residence time is 5 minutes, a sample frequency of $60-90h^{-1}$ can be achieved. The detection limit and relative deviation are $0.05mg.ml^{-1}$ and 4%, respectively. The recovery of this method is 96 - 110%, and the determination results of the method are greatly agreement with standard colorimetric method.

• 분석과학
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• 제8권4호
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• pp.539-543
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• 1995

The on-line SPE-HPLC coupling system was developed for the efficient separation and determination of trace pesticides, such as phenoxyacetic acids and esters, and triazines in aqueous solutions. By using the developed SPE-HPLC on-line system, the band broadening usually observed in single precolumn switching mode was greatly reduced, consequently, the quantitative determination of trace pesticides could be achieved, Besides, since most of the analytes preconcentrated by SPE column could be injected directly into HPLC system, the limit of detection can be improved down to ppt level.

• 분석과학
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• 제8권4호
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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%.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1515-1518
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• 2009

The objective of this study was to compare 3 extraction methods including, solid phase extraction (SPE), acetonitrile extraction, and methanol extraction, for their usefulness as extraction methods to determine capsaicinoids. The determination of capsaicinoids in the extracts was carried out on a reverse-phased high performance liquid chromatography (HPLC) using a fluorescence detector. Three extraction methods, i.e., SPE, acetonitrile extraction, and methanol extraction were compared for the quantification of capsaicinoids using raw peppers and pepper powder. The highest analytical values were observed using methanol extraction and the lowest values using SPE. Also, the analytical method validation parameters such as accuracy, precision, limit of detection, limit of quantitation, and specificity were calculated to ensure the method's validity. This method provides a fast and accurate approach for the determination of capsaicinoids in peppers.

• 약학회지
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• 제33권3호
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• pp.156-160
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• 1989

A gas-chromatographic determination method of thiamin which use a quantitative cleavage of thiamin to 4-methyl-5-(2-hydroxyethyl)thiazol [I] and solvent extraction of the analyte prior to GC injection was modified. A column chromatographic procedure using a reversed phase, high capacity solid phase cartridge was applied to the clean-up of the analyte. Thiazol derivative[I] was quantitatively recovered upon the column method. Acetanilide, an internal standard, has a good recovery through the analytical procedure. The method has analytical precision of 2% or less in the coefficient of variation.

• 분석과학
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• 제14권6호
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• pp.540-544
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• 2001

Determination of cyanide ion has been studied by adsorptive stripping voltammetry using hanging mercury electrode. Cyanide ion complexed with copper ion is adsorpbed on the electrode and oxidised at the positive potential scan. Optimal conditions of CN determination were found to be ; supporting electrolyte solution ; 0.1 M NaCl of ammonium buffer at pH 10, accumulation potential; -800 mV vs Ag/AgCl, accumulation time ; 300 s, scan rate ; 50mV/s. The linear concentration of cyanide ion was observed in the range $1{\times}10^{-8}$, $1{\times}10^{-7}M$. The detection limit(n/s=3) was $0.13{\mu}g/L$($5{\times}10^{-9}M$) with 3.5% RSD.

• 분석과학
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• 제31권3호
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• pp.134-142
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• 2018

The uranium isotopic ratio in environmental samples around nuclear facilities is important because it reveals information regarding illegal activities or anthropogenic pollution. Determination of uranium isotopes, however, is a challenging task requiring much labor and time because of the complex separation procedures and lengthy process. In this study, a rapid determination method for uranium isotopes in environmental samples was developed using. The sample was completely decomposed using the alkali fusion method. The separation procedure using extraction chromatography (UTEVA) was simplified in a single step without any further removal process for Si and major matrix elements. The established method can be completed within 3 h from sample dissolution to ICP-MS measurement. Most matrix elements and uranium isotopes in the soil samples were well separated and purified. Five types of were used to assess the method's accuracy and precision for a rapid uranium analysis method. The analytical accuracy for all CRM samples ranged from 95.1 % to 97.8 %, and the relative standard deviation was below 3.9 %. From the analytical results, one may draw conclusions that the evaluated method for uranium isotopes using alkali-fusion, the extraction chromatography process, and ICP-MS measurements is fast and fairly reliable owing to its recovering efficiencies. Thus, it is expected that the evaluated method can contribute to the improvement of environmental monitoring ability.

• 분석과학
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• 제8권4호
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• pp.575-582
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• 1995

A new analytical procedure using a serial dual electrode detector was developed for the analysis of amino acids and proteins. Bromine was generated at the upstream electrode and detected by the downstream electrode. The presence of amino acids and proteins was shown to lower the downstream current but with no apparent effect on the upstream current. This indirect mode of detection can be applied to the determination of amino acids and proteins which are electrochemically inactive or too large to be accessible to the electrode surface for electron exchange. The method is shown capable to determine various amino acids (cystine, tyrosine, lysine, tryptophan, glycine, methionine and arginine) and proteins (cytochrome c, hemoglobin, HAS, a-Amylase, Conalbumin I, Catalase and Myglobin) with linear working range for amino acids between $10^{-6}$ to $10^{-3}M$ and total proteins between $10^{-7}$ to $10^{-3}M$. The method has been applied for the analysis of amino acids and total protein in food using Flow Injection Analysis with results obtained comparable to those using the traditional analytical procedure. Use of pulse generation technique was shown to produce a more stable flow injection analysis peaks for repetitive determination than the use of conventional constant current method which showed increase of the background current after determination over 200 minutes. The pulse method was found to give stable baseline even after 400 minutes. Thus, the method is shown able to provide a suitable analytical procedure for automatic analysis of amino acids and proteins in food by flow injection analysis.

• 분석과학
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• 제8권1호
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• pp.101-105
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• 1995

The concentration of zinc of the Reumatoid Arthritis patients has been determined by ICP-AES, and the analytical results are discussed. It is observed that the zinc concentration is largely affected by the length of scalp hair. The concentrations of zinc in the distal end are much higher than that of the proximal end.

• 분석과학
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• 제8권4호
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• pp.771-778
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• 1995

The authors have developed an analytical method for determining trace amounts of 285 kinds of chemicals in natural waters by GC-ion trap MS. The results of overall recovery tests at $0.1{\mu}g/l$ showed that the mean recovery was 92.1% and the mean relative standard deviation was 10.8%. The mean of the method detection limits was $0.036{\mu}g/l$. From the results of analysis of real samples, it was confirmed that this method is useful to elucidate the concentration levels and the fate of chemicals in the aquatic environment.