• Journal of Radiation Protection and Research
• /
• v.37 no.4
• /
• pp.213-218
• /
• 2012

Alpha spectrometry has been typically used for determination of the uranium isotopes in soil. For a number of uranium analysis in soil samples, rapid sample digestion with limited quantities of mixed acid containing HF will give a contribution for effective management of uranium analysis. Microwave digestion system is evaluated for rapid sample digestion using reference uranium soil (IAEA-375 soil). For completion of 0.5 g of soil digestion by microwave, 3 ml of HF in a 10 ml of mixed acid is minimum requirement volume for completed soil digestion for 80 minutes. Microwave digestion is timely effective techniques for uranium measurement using alpha spectrometry compared to the other methods (open vessel digestion, closed vessel digestion) due to rapid sample digestion. In addition, it can be reduced the occurrence of hazardous substances by minimizing the amount of HF.

• Analytical Science and Technology
• /
• v.26 no.6
• /
• pp.375-380
• /
• 2013

Ammonium biflouride ($NH_4HF_2$) digestion was studied for germanium analysis in rock and sediment by inductively coupled plasma mass spectrometry (ICP/MS). QLO-1 and SDO-1 are used for reference materials from USGS. Sediment, basalt and ball clay for GeoPT were chosen as real samples. The loss of germanium in open vessel digestion was well known which can be caused by easy transformation to volatile compounds. But ammonium bifluoride digestion could suppress loss of germanium in open vessel digestion. Germanium recovery was not influenced by hydrogen peroxide with ammonium bifluoride digestion. Furthermore, the new method was simple and rapid in germanium analysis by ICP/MS. MDL(method detection limit) was 0.015 ${\mu}g/g$ and germanium recovery was 106~128%.

• Journal of Soil and Groundwater Environment
• /
• v.6 no.1
• /
• pp.63-83
• /
• 2001

Heavy metals are extracted from stream sediments, roadside soils and sediments and soils and tailings from mining area using partial extraction, acid digestion and HF-digestion. Compared to amounts of heavy metals extracted using partial extraction, those extracted using acid digestion are higher by 2.0∼221 times in Cu, 2.4∼2806 times in Pb, 1.3∼121 times in Cd, 14. 1∼1300885 times in Fe, 1.2∼272 times in Mn, 1.3∼373 times in Zn, 2.2∼1735 times in Cr. There is no special relationship between the extracted amounts of heavy metals using partial extraction and those using acid digestion. However, it is possible that there is a certain relationship between those using acid digestion and those using HF-digestion. Although partial extraction, which extracts less amounts of heavy metals (Cd, Cu, Pb) from soil compared to acid digestion, is used in domestic standard method for examination of soil, domestic soil standard for heavy metals in non-agricultural and industrial areas is higher than soil standard in foreign countries which use acid digestion. For improvement of the domestic standard method for assessment of soil, it is suggested to lower the domestic soil standard for heavy metals or to change pretreatment method for extracting heavy metals from partial extraction to acid digestion with modifying the soil standard.

• Journal of the Korean Chemical Society
• /
• v.43 no.4
• /
• pp.412-417
• /
• 1999

The analytical results obtained by microwave digestion and acid digestion methods for sample pretreatment to determine metal impurities in silicon wafer by inductively coupled plasma-mass spectrometry (ICP-MS) were compared. In order to decompose the silicon wafer, a mixed solution of $HNO_3$ and HF was added to the sample and the metal elements were determined after removing the silicon matrix by evaporating silicon in the form of Si-F. The recovery percentages of Ni,Cr and Fe were found to be 95∼106% for both microwave digestion and acid digestion methods. The recovery percentage of Cu obtained by the acid digestion method was higher than that obtained by the microwave digestion method. For Zn, however, the microwave digestion method gave better result than the acid digestion method. Fe was added to a silicon wafer using a spin coater. The concentration of Fe in this sample was determined by lCP-MS, and the same results were obtained in the two pretreatment methods.

• The Journal of the Petrological Society of Korea
• /
• v.25 no.2
• /
• pp.107-119
• /
• 2016

Trace element abundances in the igneous rocks are important data for petrogenetic interpretation. Their concentrations are generally measured using ICP-MS from the dissolved solution. The acid digestion of rock powder can be performed by conventional teflon vial or pressure bomb. In this paper, we investigated a problem that happened during acid digestion experiment using conventional teflon vial or pressure bomb of BCR2 and GSP2 USGS rock standard materials. The results show that the measured concentrations of the elements like Cr, Ni, Zn, Ta, W in the BCR2 are different from the recommended values of USGS whereas those of the elements like Rb, Sr, Zr, Hf, Ta, W in the GSP2 are different from those values. Our experiment shows that defect of specific elements like Cr, Ni may happen during the sample digestion. Our results also indicate that the Cr, Ni, W, Zr, Hf, Ta concentration obtained based on an acid digestion of geological samples need to be careful in their geochemical interpretation.

• Applied Chemistry for Engineering
• /
• v.10 no.4
• /
• pp.568-575
• /
• 1999

Two different digestion procedures for the simultaneous determination of major and platinum-group element(PGE) in spent automobile catalysts containing PGE and silicates by inductively coupled plasma atomic emission spectrometry(ICP-AES) are compared. Combinations of mixed aids using HF, $HNO_3$, HCl, $HClO_4$, $H_2O_2$, and $H_3BO_3$ are utilized for the hot plate dissolution method and the closed-vessel microwave digestion method, The latter method has been shown to be relatively superior in terms of recovery, analysis time, and amount of aqua regia (3 parts HCl + part $HNO_3$ required to dissolve PGE in comparison with conventional open vessel hot-plate dissolution. The best results were drawn from the following conditions: In closed Teflon PFA vessels under microwave heating with temperature/pressure regulation, a 0.25 g portion of sample was digested in 2 mL of HF, 2 mL of $HNO_3$ and 6mL of HCl under the pressure of 200 psi(13.79 bar) at $180^{\circ}C$ for 1hr, followed by a second digestion stage with 16 mL of 5%(w/v) boric acid under the pressure of 20 psi(1.38 bar) at $100^{\circ}C$ for 10 min. After the microwave heating, the sample was post-treated with 10 mL of aqua regia twice by hot-plate heating. This condition gives the PGE recovery within 85~110% and the relative standard deviations within 2%. The method developed can therefore be regarded as an alternative method for routine analysis of spent automobile catalysts.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.2
• /
• pp.159-163
• /
• 2001

Si3N4 powder has been analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). The sample was dissolved by high-pressure acid digestion with HF, H2SO4 (1+1), and HNO3 mix ture. This technique is well suited for the impurity analysis of Si3N4 because the matrix interference is eliminated. A round-robin samples trace elements, such as Ca, W, Co, Al, Fe, Mg, and Na, were determined. For the direct analysis, slurry nebulization of 0.96 mm Si3N4 powder also has been studied by ICP-AES. Emission intensities of Fe were measured as ICP operational conditions were changed. Significant signal difference between slurry particles and aqueous solution was observed in the present experiment. Analytical results of slurry injection and high-pressure acid digestion were compared. For the use of aqueous standard solution for calibration, k-factor was determined to be 1.71 for further application.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.11a
• /
• pp.298-301
• /
• 2000

Heavy metals are extracted from stream sediments, roadside soils and sediments and soils and tailings from mining area using partial extraction, acid digestion and HF-digestion. Compared to amounts of heavy metals extracted using partial extraction, those extracted using acid digestion are higher by 2.0∼220.9 times in Cu, 2.4∼2806.1 times in Pb, 1.3∼121 times in Cd, 14.1∼1300885 times in Fe, 1.2∼271.5 times in Mn, 1.3∼372.5 times in Zn, 2.2∼1734.5 times in Cr. Although partial extraction, which extracts less amounts of heavy metals from soil compared to acid digestion, is used in domestic standard method for examination of soil, domestic soil standard for heavy metals in non-agricultural and industrial areas is higher than soil standard in foreign countries which use acid digestion, For improvement of the domestic standard method for assessment of soil, it is suggested to lower the domestic soil standard for heavy metals or to change pretreatment method for extracting heavy metals from partial extraction to acid digestion with modifying the soil standard.

• Analytical Science and Technology
• /
• v.27 no.6
• /
• pp.352-356
• /
• 2014

Various studies have been done to improve the properties of the steel by adding boron to the steel. Some studies have reported on the analysis of the boron in steel by AAS (atomic absorption spectrometry), ICP-OES(inductively coupled plasma-optical emission spectrometry), ICP-MS (inductively coupled plasma/mass spectrometry). The volatile loss of boron of steel in sample digestion and the separation procedure for avoiding matrix effect by high concentration of iron are difficulties for determination of boron in steel. The method to determine boron in steel by ICP-MS was developed without volatilization of boron in sample digestion step with $HNO_3-NH_4HF_2$ digestion method, and the additional separation process for avoiding matrix effect. Complete decomposition of steel with $HNO_3-NH_4HF_2$ digestion method, and boron determination by ICP-MS in the matrix of high concentration of iron were possible. Quantitative recoveries of boron in certified standard steel by new method in this study were 103 to 111%, and the relative standard deviation is less than 5%. The method detection limit was $1.17{\mu}g/g$.

• Analytical Science and Technology
• /
• v.23 no.6
• /
• pp.511-517
• /
• 2010

Dissolution procedure of vanadium pentoxide, which is widely used as a catalyst for production of sulfuric acid or an oxide reaction of the numerous organic compounds, was investigated. Reagent of vanadium pentoxide was completely dissolved in aqua regia-$H_2O_2$-HF solution, but plate type of vanadium pentoxide sample was not clearly dissolved with mixed acids. Thus, in order to establish the dissolution procedure for plate type of vanadium pentoxide, the solubility of vanadium pentoxide was investigated through comparison of acid treatment-fusion and microwave digestion methods. The optimized acid for dissolution of vanadium compound was found to be mixing acids of aqua regia, $H_2O_2$ and HF. Acid-fusion and microwave digestion methods have a similar property in the solubility of vanadium compound, but the latter was more quick and convenient procedure. The content of vanadium pentoxide was found to be $97.9{\pm}0.9%$ using an inductively coupled plasma atomic emission spectrometer after dissolution of a sample with the microwave digestion system.