• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.440-446
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• 2005

A method is described for the determination of dibutyltin (DBT) in sediment by isotope dilution using liquid chromatography inductively-coupled plasma/mass spectrometry (LC-ICP/MS). To achieve the highest accuracy and precision, special attentions are paid in optimization and evaluation of overall processes of the analysis including extraction of analytes, characterization of the standards used for calibration and LC-ICP/MS conditions. An approach for characterization of natural abundance DBT standard has been developed by combining inductively-coupled plasma/optical emission spectrometry (ICP/OES) and LC-ICP/MS for the total Sn assay and the analysis of Sn species present as impurities, respectively. An excellent LC condition for separation of organotin species was found, which is suitable for simultaneous DBT and tributyltin (TBT) analysis as well as impurity analysis of DBT standards. Microwave extraction condition was also optimized for high efficiency while preventing species transformation. The present method determines the amount contents of DBT in sediments with expanded uncertainty of less than 5% and its result shows high degree of equivalence with reference values of an international inter-comparison and a certified reference material (CRM) within stated uncertainties.

• 한국재료학회지
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• 제13권10호
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• pp.635-639
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• 2003

We investigated dry etching of GaAs and AiGaAs in a high density planar inductively coupled plasma system with BCl$_3$and BCl$_3$/Ar gas chemistry. A detailed etch process study of GaAs and ALGaAs was peformed as functions of ICP source power, RIE chuck power and mixing ratio of $BCl_3$ and Ar. Chamber process pressure was fixed at 7.5 mTorr in this study. The ICP source power and RIE chuck power were varied from 0 to 500 W and from 0 to 150 W, respectively. GaAs etch rate increased with the increase of ICP source power and RIE chuck power. It was also found that etch rates of GaAs in $15BCi_3$/5Ar plasmas were relatively high with applied RIE chuck power compared to pure 20 sccm $BCl_3$plasmas. The result was the same as AlGaAs. We expect that high ion-assisted effect in $BCl_3$/Ar plasma increased etch rates of both materials. The GaAs and AlGaAs features etched at 20 sccm $BCl_3$and $15BCl_3$/5Ar with 300 W ICP source power, 100 W RIE chuck power and 7.5 mTorr showed very smooth surfaces(RMS roughness < 2 nm) and excellent sidewall. XPS study on the surfaces of processed GaAs also proved extremely clean surfaces of the materials after dry etching.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.31-36
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• 2003

We investigated dry etching of GaAs and AlGaAs in a high density planar inductively coupled plasma system with $BCl_3$ and $BCl_3/Ar$ gas chemistry. A detailed process study as a function of ICP source power, RIE chuck power and $BCl_3/Ar$ mixing ratio was performed. At this time, chamber pressure was fixed at 7.5 mTorr. The ICP source power and RIE chuck power were varied from 0 to 500 W and from 0 to 150 W, respectively. GaAs etch rate increased with the increase of ICP source power and RE chuck power. It was also found that etch rate of GaAs in $BCl_3$ gas with 25% Ar addition was superior to that of GaAs in a pure $BCl_3$ (20 sccm $BCl_3$) plasma. The result was same with AlGaAs. We expect that high ion-assisted effect in $BCl_3$/Ar plasma increased etch rates of both materials. The GaAs and AIGaAs features etched at 20 sccm $BCl_3$ and $15BCl_3/5Ar$ with 300 W ICP source power, 100 W RIE chuck power and 7.5 mTorr showed very smooth surfaces(RMS roughness < 2 nm) and excellent sidewall. XPS study on the surfaces of processed GaAs also proved extremely clean surfaces of the materials after dry etching.

• 분석과학
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• 제25권4호
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• pp.223-229
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• 2012

시료 에어로졸에 의한 광산란 신호를 이용하여 ICP 분석신호를 보정하였다. 자체 제작한 초음파 분무기에서 발생되는 에어로졸에 대하여 다이오드나 He-Ne 레이저를 사용하여 광산란신호를 얻고 이를 기준으로 하여 분석신호의 변동에 대하여 보정하였다. 그 결과 Be, Pb 및 Co의 경우에 short-term (1분 이하)에 대한 신호의 RSD가 기존의 평균 3.4% 에서 0.9% RSD 이하로 큰 개선이 되었으며, 10분 정도의 long-term안정도는 14.9%에서 4.2%로 개선되었다. 이 방법은 펄스형태의 시료도입뿐 아니라 연속적 분무에서도 분무기의 안정성이 부족한 경우, 정밀도의 개선에 매우 유용하다. Long-term의 안정도 개선을 위해서는 광산란셀에서의 안정도 및 검출기의 잡음개선과 분무장치와 플라즈마 사이에서의 에어로졸 응축등에 의한 잡음의 개선이 필요한 것으로 보인다.

• 분석과학
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• 제27권6호
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• pp.269-276
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• 2014

후 컬럼 동위원소 희석법의 불확도를 HPLC-ICP/MS에서 Selenomethionine을 분석할 경우에 대하여 간단히 연구하였다. 주요하다고 생각한 오차의 원인으로 셀레늄 동위원소 용액의 농도와 흐름속도, 스파이크 용액과 시료 용액에서의 셀레늄 원자량, 그리고 스파이크된 시료용액에서 측정된 동위원소의 비를 선택하였다. 각 요인에 따른 불확도를 구하고 전체 농도의 불확도에 미치는 요인을 계산한 결과, 각각에 대하여 54.4%와 0.61%, 0.0072%와 0.018%, 그리고 45.0%를 얻었다. 가장 큰 요인은 스파이크 동위원소 용액의 농도이며 두 번째는 스파이크가 첨가된 시료용액에서의 동위원소비이었다. 스파이크 용액의 질량흐름속도와 원자량의 불활도는 크게 영향을 끼치지 못하였다. 계산된 전체불확도는 $126.30ng{\cdot}g^{-1}$ SeMet 표준용액에 대하여 $1.46ng{\cdot}g^{-1}$으로서 실험결과는 $127.09ng{\cdot}g^{-1}$을 얻었고 상대불확도는 1.20%이었다.

• 한국환경복원기술학회지
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• 제16권6호
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• pp.63-75
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• 2013

The purpose of the study is investigating the price fluctuation of landscaping plants in the Information on Commodity Prices(ICP) and the posted price fluctuation of landscaping plants of Public Procurement Service(PPS) recent 10 years. It also provides the basic information which can be applied to production and sales of landscaping plants, comparing with general price index. The major findings of the study are as follows. First, The price of investigated plants of PPS has increased about 4.56% in average recent 10 years. Among this increase, of evergreen tree was predominant. On the other hand, landscaping trees price of ICP has increased about only 2.34% in average. Secondly, The result shows that average price of investigated plants of PPS is positively related with the price of ICP. For this reason, we found that prices of ICP and of PPS move together in most case. However, we found that there are no relation between Consumer Price Index(CPI), Producer Price Index(PPI) and Agricultural Price Index(API). Therefore, price fluctuation of landscaping trees moves regardless of normal price fluctuation in general. Third, even though result shows that price index of evergreen trees, deciduous trees and shrubs are weakly related with normal price index partly, it was not high enough to be significant. According to the result, we found that price of landscaping plants is not related with market situation. For this reason, we thought that there are some difficulties for the reasonable production and sales of landscaping plants because the price is somewhat decided by rule of thumb. Therefore, understanding the composition of cost and making prediction by price fluctuation available are needed so that it can be practically conducive to reasonable production and sales.

• 대한수의학회지
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• 제52권2호
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• pp.69-74
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• 2012

The analytical method of trace toxic metals in livestock products was confirmed and validated through certified reference material (CRM) and the international proficiency tests. There are some difficulties to determine low levels of toxic metals in livestock products because of interferences due to the matrix. The recoveries of CRM (NIST 1577c) ranged from 73.9 to 119% for lead and from 86.4 to 111% for cadmium in bovine liver. The international proficiency tests were carried out with the milk powder and cocoa powder samples including metals provided by Food Analysis Performance Assessment Scheme (FAPAS$^{(R)}$, UK). The test samples were prepared by microwave digestion using solution of $HNO_3:H_2O_2:H_2O$ (v/v/v = 5 : 2 : 4) and analyzed by ICP/MS. The analytical result of cadmium in milk powder was $121{\mu}g/kg$ with -0.3 of the z-score compared to the assigned value of $131{\mu}g/kg$ by FAPAS$^{(R)}$. The analytical results of lead and cadmium in cocoa powder were $29.2{\mu}g/kg$ and $97.6{\mu}g/kg$, respectively, which satisfied the assigned values of $34.2{\mu}g/kg$ for lead and $126{\mu}g/kg$ for cadmium by FAPAS$^{(R)}$. It is verified that the analytical method is accurate and reliable to determine trace lead and cadmium in livestock products by microwave digestion and ICP/MS.

• Korean Chemical Engineering Research
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• 제43권1호
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• pp.76-79
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• 2005

Magnetic random access memory(MRAM) 소자재료로 사용되고 있는 NiFe, NiFeCo, Ta 등의 박막을 $Cl_2/Ar$ 유도 결합 플라즈마를 이용하여 식각하였다. NiFe와 NiFeCo의 식각 속도는 특정 ICP 공급 전력에서 최대값을 나타냈지만, Ta의 식각 속도는 ICP 공급 전력이 증가함에 따라 증가하였다. RF 하부전극 전력이 증가하면서 자성박막의 식각 속도는 증가하였지만, 공정압력과 $Cl_2$의 농도가 증가함에 따라 점진적으로 감소하였다. 식각 후에 염소에 의한 표면 부식을 방지하기 위해 이온수로 5분간 세척하였다. 식각 프로파일은 $Cl_2$ 농도가 50%일 경우에 식각 단면에 식각 잔유물들이 존재하지 않는 부드러운 단면을 얻을 수 있었다.

• 한국대기환경학회지
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• 제21권4호
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• pp.423-430
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• 2005

This study was investigated with sample digestion techniques and a reliability of the analytical results for a quantitative analysis of a standard reference material ('urban particulate matter', SRM 1648). The metallic elements were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) with closed vessel microwave acid digestion method and atomic absorption spectroscopy (AAS). Quality control of the overall analytical procedures for metallic element determinations of standard reference material were estimated by analysis of a SRM 1648. Three digestion solutions $(type\;1:\;HNO_3,\;type\;2:\;HNO_3\;and\;H2O_2(4'1)\;mixture,\;type\;3:5.55\%\; HNO_3\;and\;16.75\%\;HCI\;mixture)$ were applied to SRM 1648. As a result, three digestion solutions used in this study are completely unable to digest Cr of SRM 1648. Reliability of Cr and As showed some errors in the digestion with digestion solution type (3) due to the influence of chlorides. Type (3) digestion solutions are sufficient to fulfill the digestion of As as well as Se in SRM 1648. ICP-MS results showed the improvement in accurate and precise determination of some trace elements like Cd, V and Pb in SRM 1648. It is important to use the proper digestion solution for each element to qualify analytical precision.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3665-3670
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• 2012

Metal-p-$NH_2$-Bn-DOTA (paraammionobenzyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid: ABDOTA) complex was synthesized and purified for bio-tagging to quantify biological target materials using laser ablation (LA)-ICP-MS. Since the preparation of a pure and stable tagging complex is the key procedure for quantification, magnetic particles were used to purify the synthesized metal-ABDOTA complex. The magnetic particles immobilized with the complex attracted to a permanent magnet, resulting in fast separation from free un-reacted metal ions in solution. Gd ions formed the metal-complex with a higher yield of 64.3% (${\pm}3.9%$ relative standard deviation (RSD)) than Y ions, 52.3% (${\pm}2.5%$ RSD), in the pH range 4-7. The complex bound to the magnetic particles was released by treatment with a strong base, of which the recovery was 81.7%. As a reference, a solid phase extraction (SPE) column packed with Chelex-100 resin was employed for separation under similar conditions and produced comparable results. The tagging technique complemented polydimethylsiloxane (PDMS) microarray chip sampling in LA-ICP-MS, allowing determination of small sample volumes at high throughputs. For application, immunoglobulin G (IgG) was immobilized on the pillars of PDMS microarray chips and then tagged with the prepared Gd complex. IgG could then be determined through measurement of Gd by LA-ICP-MS. A detection limit of 1.61 ng/mL (${\pm}0.75%$ RSD) for Gd was obtained.