• 환경위생공학
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• 제16권1호
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• pp.91-101
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• 2001

In order to propose a optimum method increasing accuracy and reproducibility in analysis of urine lead levels, we compared matrix modifier addition method and microwave digestion method. The results were as follows ; 1. Where the concentration of $Pd(NO_3)_2$(matrix modifier) was $50mg/{\ell}$, and ashing temperature was $900^{\circ}C$, the results were optimum. In case of matrix modifier addition method, the average coefficient of variation (CV) of normal man was 24.1%, and lead worker was 7.9%. The average urine lead levels of standard were $10.42\mu{g}/{\ell}$ and $19.89\mu{g}/{\ell}$ , the accuracies compared to reference values were 97.0% and 92.6%, respectively. 2. Microwave digestion temperature($160~180^{\circ}C$), time(15~25min) and the ratio of urine/ashing acid(1:1~4:1) did not significantly affect lead absorbance and background absorbance. Therefore we set up a optimum analytical conditions as follows: temperature, $160^{\circ}C$; time, 15min; the ratio of urine/ashing acid, 4:1. after samples were digested by the above analytical conditions, lead absorbance and background absorbance was measured at $450^{\circ}C$ as ashing temperature. The average coefficient of variation (CV) of normal man was 12.4%, and lead worker was 6.2%. The average urine lead levels of standard urine were $10.66\mu{g}/{\ell}$ and $23.31\mu{g}/{\ell}$, the accuracies compared to reference values were 99.3% and 103.9%, respectively. From the results, we suggest that microwave digestion method is a more favorable method than matrix modifier addition method because of easiness to reduce organic matter, possibility to analysis at low temperature and accuracy.

• 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.

• 한국산업보건학회지
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• 제26권1호
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• pp.48-57
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• 2016

Objectives: This study was conducted to evaluate the accuracy and precision of airborne metal analysis using polyvinyl chloride(PVC) membrane filter by pretreatment methods. Methods: A total of 75 spiked PVC samples for Cr, Fe and Mn ranged from 6 ug/sample to 40 ug/sample were used to evaluate recovery rates for three pretreatment methods: acid extraction, hot plate ashing and microwave digestion. For Mn, an additional 75 spiked mixed cellulose ester(MCE) membrane filters were analysed to compare the recovery rates of PVC samples. All samples were analysed with an inductively coupled plasma optical emission spectrometer(ICP-OES) and manganese samples were additionally analyzed by atomic absorption spectrometer(AAS). Results: The overall mean recovery rates of PVC samples for Cr, Fe and Mn were 90% or higher regardless of pretreatment methods, but there were statistically significant differences in recovery rates for Cr(p<0.05) and Mn(p<0.01) samples by pretreatment methods. The biases and the coefficient variations of PVC samples for three metals pretreated with three kinds of pretreatment methods ranged from 1.7% to 4.7% and from 1.6% to 6.5%, respectively. The manganese PVC samples pretreated by microwave digestion and analyzed with ICP-OES had the lowest bias at 1.9% and also showed lower bias than the bias for MCE samples, 2.7%. Conclusions: In order to accurately analyze the metals sampled with PVC membrane filters, microwave digestion and ICP-OES can be recommended.

• 한국농공학회논문집
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• 제62권2호
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• pp.17-29
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• 2020

The objective of this study was to find an optimum methane yield condition in anaerobic digestion of sewage sludge with microwave pretreatment. The pretreatment process was carried out using a lab scale industrial microwave unit (2,450 MHz frequency). The digestion efficiency of pretreated sludge was evaluated by biochemical methane potential (BMP) test. Box-Behnken design and Response Surface Analysis (RSA) were applied to determine the optimal combination of sludge mixing ratio (0 to 100%), power (400 to 1600 W), holding time (0 to 10 min) and pretreatment temperature (60 to 100℃). BMP test results showed that Volatile Solid (VS) removal efficiency was up to 48% at a condition of 0% for mixing ratio, 1600 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. Methane production was up to 832.3 mL/g VS_removed at a condition of 50% for mixing ratio, 1000 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. The results of the variance analysis (ANOVA) showed that the p-value of the power and pretreatment temperature among the independent variables were significant (p<0.05), and in particular, the pretreatment temperature significantly affected on the solubilization and methane production. The optimum condition for the maximum methane yield (847 mL/g VS_removed) was consist of 38.4% of mixing ratio, 909.1 W of power, 4.1 min of holding time, and 80℃ of temperature within the design boundaries.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.128-131
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• 2003

The effect of microwave irradiation on waste activated sludge was investigated in order to improve solubilization. a different levels of microwave irradiation time were varied within a range from 1 min to 15 min. When WAS was pretreated at 1, 3, 5, 7, and 15 min, the SCOD concentration increased according to microwave irradiation time. A simple batch procedure was used to measure the VFA potential, i.e. the amount of VFA that can be formed through digestion of organic constituent in sludge. At equilibrium point, TVFA in the case of 1, 3, 5, 7 and 15 min microwaved sludges was 8%, 122%, 243%, 279% and 232% higher than that in the case of raw sludge, respectively.

• 분석과학
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• 제25권6호
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• pp.402-409
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• 2012

연속흐름 수소화물 생성-유도결합 플라스마 원자 방출 분광기(FI-HG-ICP-AES) 이용하여 플라스틱 소재에 함유된 비소를 정량하기 위한 조건을 얻었다. 플라스틱 시료를 습식 산 분해 방법 및 마이크로파 산 분해 방법으로 전처리하여 시험 용액을 조제하였다. 인증표준물질(CRM)인 CRM-EC680k 및 CRM-EC681k를 사용하여 측정한 값과 인증값을 비교하여 분석 방법의 재현성 및 정확성을 확인하였다. 습식 산 분해 방법 및 마이크로파 산 분해 방법으로 전처리하여 FI-HG-ICP-AES로 측정한 결과 CRM-EC680k의 경우에는 4.1~4.3 mg/kg (인증값 $4.1{\pm}0.5$ mg/kg)이고, CRM-EC681k의 경우에는 28.9~30.6 mg/kg (인증값 $29.1{\pm}1.8$ mg/kg)이었다.

• 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.

• 분석과학
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• 제11권4호
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• pp.297-304
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• 1998

무기 priority pollutants의 분석에 미치는 매질의 영향을 살펴보기 위하여 도금, 피혁, 제지, 전기, 염색 sludge에 7종의 무기 priority pollutants(Ni, Cr, Cu, Zn, Pb, Cd, Hg)를 첨가하고 EPA 3050방법, 환경처의 폐기물공정시험방법 및 폐기물공정시험방법을 수정한 본 연구실 방법으로 비교 연구하였다. EPA 3050법에 따라 추출한 경우 Hg를 제외하고 평균회수율은 95.5%, 폐기물공정시험방법의 용출시험 방법에 따라 추출한 경우는 11.1%, 그리고 본 연구실에서 폐기물공정시험방법을 수정한 추출법의 경우는 27.7%의 평균 회수율이 나타났다. 매질에 따른 digestion에 대한 영향을 살펴보기 위하여 추출법에 의해 추출된 용액을 MDS(microwave digestion system)와 $HNO_3+HClO_4$ digestion 방법으로 회수율을 비교하였다. 유기 및 무기 매질에 대한 영향을 살펴보기 위하여 유기 매질인 경우는 triethanol amine, 무기 매질인 경우는 $FeCl_3{\cdot}6H_2O$와 $AlCl_3{\cdot}6H_2O$를 첨가하여 분석용 시료를 조제하고 AAS 및 HG-AAS로 회수율을 구하였다. 유기 및 무기 매질을 첨가한 시료가 첨가 하지 않은 시료 보다 회수율이 낮게 나타남에 따라 매질에 의한 영향을 받는 것으로 조사되었다. Hg는 MDS로 digestion하는 것이 회수율이 높게 나타났으며, Hg를 제외한 다른 원소는 $HNO_3+HClO_4$로 digestion 하는 것이 회수율 증가를 나타냈다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2019년도 춘계학술논문요약집
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• pp.401-402
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• 2019

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 춘계학술논문요약집
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• pp.281-282
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• 2017