• Analytical Science and Technology
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• v.11 no.4
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• pp.281-291
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• 1998

An analytical method for the simultaneous measurement of trace Cu, Sn, and Bi in blood and urine has been investigated by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Microwave oven was used for the pretreatment of blood samples using nitric acid and hydrogen peroxide in a closedvessel digestion system with 1 mL whole blood for 8 minutes. Amberlite IRC-718 resin was used as a solid phase in solid-liquid extraction technique for the removal of matrix interferences such as Na, S, P, and other polyatomic ion species. Detection limits for Cu, Sn, and Bi by this method were 0.000375 ng/mL, 0.000297 ng/mL, and 0.000174 ng/mL, respectively. Recoveries of 99.1% for Cu, 102.5% for Sn, and 98.4% for Bi were obtained for the standard spiked NIST SRM 955a blood sample. The developed method was applied for whole real blood and urine samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.3
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• pp.313-318
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• 1984

Some chemical, biochemical and physical treatments on the baker's yeasts (Saccharomyces cerevisiae) before 12-hour digestion at $50^{\circ}C$ were made to accelerate their autolysis. Dilute alkali treatment with 0.01N-NaOH solution showed a considerable increase in soluble nitrogen extraction only in the 6-hour initial autolysis. The addition of fresh yeast autolysate, 10% to the yeast slurry, could increase the autolysis rate from 65% to 83%. Microwave treatment of yeast slurry for 40 seconds also raised the autolysis rate by about 15%, while longer exposures to the microwave accompanying high temperatures repressed the autolysis process. Extrusion of the yeast cells with high pressures of 16,000 to 20,000 psi brought about significantly higher autolysis rate until the digestion time of 9 hours, but thereafter it showed a gradual drop in soluble nitrogen extraction.

• The Journal of the Petrological Society of Korea
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• v.3 no.1
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• pp.41-48
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• 1994

Three USGS rock standards (G-2, W-2, and BHVO-1) are decomposed by three different methods, such as open beaker, microwave oven, and alkali fusion method, to compare the effect of decomposition methods for trace elememt analysis in the rock samples. Solubilized trace elements are measured with inductively coupled plasma mass spectrometer (ICP-MS). Generally the analytical results of trace elements between open beaker and microwave digestion method are not different. In case of alkali fusion method, some volatile elements such as Pb, Cu, and Rb are considerably lost. Using acid digestion method, Zr and Hf concentrations are lowered in case that these elements are concentrated in refractory minerals. The concentrations of rare earth elements are generally consistent with the recommended values, but due to large dilution factor, there are some analytical problems in alkali fusion method.

• Analytical Science and Technology
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• v.36 no.5
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• pp.216-223
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• 2023

Aluminium (Al) is one of the major elements in rocks and its concentration can be varied, depending on different rock types as well as sources. The present study aimed to propose an analytical method based on the UV-Vis as a cheap, simple, and common instrument equipped in most laboratories for Al quantification in rocks after the microwave assisted acid digestion. The aluminone and 8-hydroxyquinoline were investigated for the colorimetric assay. The results show that the 8-hydroxyquinoline reagent was more favorable in terms of the minimized affects of the potential interferences present in the digested solutions, i.e., Fe³⁺, Si⁴⁺ and F^-. The calibration curve was constructed from 0.10 mg/L to 3.00 mg/L with the goodness of linearity (R² = 0.9996). The limits of detection and quantification (LOD and LOQ) were estimated, i.e., 0.029 mg/L and 0.087 mg/L, respectively. The 8-hydroxyquinoline was applied to real rock samples, demonstrating favorable precision (RSD = 0.34 %-1.8 %) and no remarkable differences were found compared to the inductively coupled plasma-mass spectrometry (ICP-MS) as a reference measurement approach.

• Analytical Science and Technology
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• v.20 no.6
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• pp.524-528
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• 2007

Variations of the twenty one metal components (Mg, Al, V, Cr, Co, Sr, Ba, Na, K Mn, Fe, Cu, Zn, As, Hg, Pb, Ca, P, Mo, Cd, Sb) were analyzed in human hair sample by inductively coupled plasma mass spectrometry (ICP-MS). The effect of bleach and permanent wave manipulation on the elemental composition of hair were investigated. It was found that the composition of hair varied with hair bleach and permanent wave. Hair sample was collected from male in the age of thirties. Hair sample (0.05 g) was added to the Teflon digestion bomb together with 1.5 mL of nitric acid and an appropriate amount of In as an internal standard. The sample was then decomposed in the microwave digestion system. In normal hair, the contents of V, Cr, Mn, Fe, Co, Cu, Zn, As, Mo, Cd, Sb and P were increased in permanent wave hair, and Mg, Al, V, Co, Sr, Ba, Na and K were increased in bleached hair. But Mg, Al, Sr, Ba, Hg, Pb, Na, K, and Ca contents were decreased with permanent wave hair, Mn, Fe, Cu, Zn, As, Hg, Pb and Ca contents were decreased with bleached hair.

• Journal of the Korean Chemical Society
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• v.37 no.9
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• pp.800-805
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• 1993

An analytical method has been developed to determine trace elements in biological samples. The biological samples are added to a laboratory-bulit Teflon bomb together with nitric acid-hydrogen peroxide mixture and enriched stable isotopes. The samples are decomposed in a microwave oven. The decomposed sample solutions are analyzed by isotope dilution inductively coupled plasma mass spectrometry. The analytical results of the biological samples agree well with the reference values.

• Analytical Science and Technology
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• v.14 no.4
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• pp.317-323
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• 2001

Dissolution procedures of Monsanto catalyst which has been used to produce acrylronitrile by ammoxidation of propylene have been studied. Optimum dissolution condition of the catalyst supported on silica was obtained by microwave digestion system with mixed of HCl, HF and $H_2O_2$. When a safety device was activated by increased pressure in microwave vessel, Bi, Fe, Mo, Sb and U were not volatilized even though silica was volatilized as $SiF_4$. Quantification results by this method were $SiO_2$ $50.5{\pm}0.4%$, $Sb_2O_3$ $29.6{\pm}0.6%$, $UO_2$ $10.2{\pm}0.1%$, $Fe_2O_3$ $6.1{\pm}0.1%$, $MoO_3$ $0.73{\pm}0.01%$ and $Bi_2O_3$ $0.49{\pm}0.01%$ by ICP-AES and the relative error was within ${\pm}10%$ except bismuth.

• Analytical Science and Technology
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• v.16 no.2
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• pp.102-109
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• 2003

Microwave digestion and solid-state extraction were studied for determination of trace aluminum{Al(III)} in human urine samples. A mixed acid of nitric acid and hydrogen peroxide was added to urine samples, organic materials were destructed in a home microwave oven and dried in a drying oven. The dried residues were dissolved in a sulfuric acid solution. The solution was eluted through a XAD-4 resin column adsorbed with 8-hydroxyquinoline(Oxine, HQ). Al(III)-8-hydroxyquinolinate complex was formed in the column and eluted with 0.5 M nitric acid solution. The Al(III) eluted was determined by graphite atomic absorption spectrophotometry. Various experimental conditions of followings were investigated for the optimization : the type of acid to dissolve the residues, the amount of HQ adsorbed on the resin, the pH of sample solutions, the type and concentration of acid to elute the complex from column and so on. The contents of Al(III) in real samples were determinated by a calibration curve method. The recovery in standard spiked samples was 94~101% and the detection limit of this procedure was 0.05 ng/mL.

• Analytical Science and Technology
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• v.15 no.4
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• pp.381-387
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• 2002

In this study, we introduced experience participated in ELPAT (Environmental Lead for Proficiency Analytical Testing) program that is administered by the American Industrial Hygiene Association and EPA. The 126 sample results of total 128 samples met reference value, as a result accepted 'proficient'. The concentration of Pb in air, paint chips, soils and dust wipes are $0.0089{\sim}0.3956mg/m^3$, 0.0500~8.9149%, 29.0${\sim}$1697 mg/kg and $18.00{\sim}900.3{\mu}g/sample$, respectively. The lead in environmental matrix prepared adequate techniques and analysed by flame atomic absorption spectrometry. The lead in air was extracted hydrochloric acid, in paint chips and soils were digested with microwave and hotplate and in dust wipes were prepared microwave digestion. No differences of each preparation techniques was found and all methods were to be proper.

• Food Science and Preservation
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• v.18 no.6
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• pp.993-997
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• 2011

The aims of this research were to determine the proximate composition of various salts and to compare two digestion methods (direct digestion without heating, and microwave digestion) for the determination of the main mineral contents of various salts. Twelve salt samples were divided into three groups of four samples each (imported, Korean gray, and Korean white salts). As a result, the NaCl contents of the Korean white, Korean gray, and imported salts were 85.1, 89.3, and 91.3%, respectively. The salts in the three groups were analyzed for their main mineral contents via AAS. The sodium (Na) content of the Korean white salt was found to be slightly lower than that of the imported salt while the magnesium (Mg) and potassium (K) contents of the Korean white salt were found to be higher than those of the imported salt. The mineral composition (% Na:Mg) obtained using microwave-assisted digestion procedures, and the other dissolutions for the subsequent sample analysis, were 89:1 (for both the imported and Korean gray salts) and 82:3 vs. 81:3 (Korean white salt), respectively. The data regarding the mineral contents and composition of the sun-dried salts obtained through the analysis method of wet digestion and the dissolution procedure were compared, and no significant difference was found between the two datasets. Consequently, in this paper, a direct dissolution procedure is suggested for the analysis of the mineral composition of salt.