• 한국동물위생학회지
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• 제29권3호
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• pp.339-346
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• 2006

Semi-micro-HPLC using a column-switching technique was developed for simultaneous determination of vitamin A and E contents in infant formula. Vitamin A and E were extracted by PDA - HPLC with reversed phase column using organic solvent and their contents in Certified Reference Material (CRM) and infant formula were determined and compared with hydrolysis method and rapid extraction. Developed method has many advantages of simple and rapid sample preparation and simultaneous determination of vitamin A and E by micro-HPLC using reversed phase column.

• 한국축산식품학회지
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• 제28권3호
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• pp.301-305
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• 2008

조제분유중의 요오드 및 염소를 신속하고 정확하게 분석하기 위해 이온선택성 전극을 이용한 분석을 실시하였다. 전극을 이용한 측정시 영향을 주는 간섭물질을 제거하기 위해 시료를 용해한 후 3% 아세트산 2 mL를 투입하고, 정제는 filter paper(No.541, Whatman, UK)를 이용하여 여과하는 방법을 선택하였다. 요오드 및 염소이온이 pH에 의해 영향을 받는 것을 확인할 수 있었으며, 0.1 N NaOH를 사용하여 pH를 7.0으로 보정하여 농도를 측정함으로써 요오드와 염소의 회수율 각각 $93.7{\pm}2.7%$와 $103.9{\pm}4.9%$의 결과를 얻을 수 있었다. 간단하고 신속한 간섭물질 제거와 정제를 통해 조제분유중의 요오드 및 염소이온의 농도를 이온전극으로 신속하고 정확하게 측정할 수 있었다.

• 한국가스학회지
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• 제22권2호
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• pp.46-51
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• 2018

산업이 급속하게 발전함에 따라 자연 대기에서 악취를 유발하는 매우 적은 양의 황화수소가 존재합니다. 매립 및 하폐수처리장에서 나오는 황화수소 성분은 대기에 존재하므로 많은 민원이 발생됩니다. 민원이 발생하는 악취가스를 측정하기 위해 $10{\mu}mol/mol$ 농도 수준의 황화수소 인증표준물질(Certified reference material)을 개발하고자 하였다. 질소 안에 $10{\mu}mol/mol$ 수준의 황화수소 가스 제조는 ISO 6142에 의한 중량법을 사용하였다. 4 개의 알루미늄 실린더에 가스 CRM을 제조하고 GC-AED로 그 농도를 확인했습니다. 제조의 불확도는 0.50 % 미만이었고, 제조일치성은 0.22 %이었다. 실린더의 내부 흡착은 1500 psi에서 0.10 %이었고 1 년 동안 장기간 안정한 것으로 평가되었다. 이 황화수소 CRM의 제조 일치성, 실린더의 흡착 및 장기 안정성에 대한 상대 확장불확도는 1.05 %(신뢰도 95 %, k = 2) 이내로 개발되었다.

• 분석과학
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• 제23권3호
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• pp.240-246
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• 2010

Salicylaldoxime (SA)이 내포되어 있는 미세결정 p-dichlorobenzene 흡착제(p-dichlorobenzene-SA)를 이용하여 시료에 흔적량으로 들어있는 Cu(II)를 예비농축시킨 후 불꽃 원자흡수분광법으로 정량하는 방법을 개발하였다. 시료 용액의 pH, 킬레이트제 salicylaldoxime의 양, 흡착제 p-dichlorobenzene-SA의 양 그리고 시료 용액의 흐름속도 등 여러 실험조건을 최적화하였다. 여러 공존이온에 대한 방해효과를 조사한 결과, $CN^1$가 다른 이온들보다 비교적 심하게 방해하였다. $1\;{\mu}g\;mL^{-1}\;CN^-$에 의한 방해효과는 Ni(II)를$20\;{\mu}g\;mL^{-1}$ 되도록 조절한 결과, 완전히 제거할 수 있었다. 본 방법으로 얻은 직선 감응범위, 상관계수($R^2$) 및 검출한계는 각각 $3.0\sim100\;ng\;mL^{-1}$, 0.9901, 및 $3.1\;ng\;mL^{-1}$ 이었다. 본 방법을 실제 시료에 적용가능 여부를 확인하기 위해 수용액 시료(폐수, 저수지물 및 시냇물)와 식품시료(오렌지 쥬스, 생계란 및 탈지분유)에 응용하였다. 회수율은 93~104% 범위이었으며, ICP-MS를 이용하여 직접 측정한 값과 본 방법으로 측정한 값을 비교한 결과, 95% 신뢰수준에서 잘 일치하였다. 본 방법을 쌀가루 인증표준물질(certified reference material, CRM) 시료에 응용해 보았으며 좋은 결과를 얻었다. 실험 결과들로부터 본 방법은 여러 실제 시료에 들어있는 Cu(II)를 농축 및 정량하는데 응용할 수 있음을 확인하였다.

• 분석과학
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• 제30권5호
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• pp.226-233
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• 2017

In general, quantitative chemical analysis in various areas including food, the environment, in vitro diagnostics, etc., requires traceability in order to increase the reliability of the measurements. Measurement traceability is a property of an unbroken chain of comparisons relating an instrument's measurements to SI units. Purity analysis is the first process for establishing traceability to SI units in chemical measurements. The purpose of this study is to develop and validate a method of purity assignment for establishing the traceability of $17{\beta}$-estradiol measurements in an in vitro diagnostics field. The establishment of this method is very important as it can be applied to the development of CRM and to the analysis of the purity of other hormones. The method of assignment of the purity of $17{\beta}$-estradiol was developed using the mass balance method and was validated through participation in an International comparison. In the mass balance method, impurities are categorized into four classes as follows: total related structure impurities, water, residual organic solvents, and nonvolatiles/inorganics. In this study, total related structure impurities were characterized by a gas chromatography-flame ionization detector (GC-FID) and a high-performance liquid chromatography-ultraviolet (HPLC-UV) detector, water content was determined by a Karl-Fisher coulometer, and total residual solvents and nonvolatiles/inorganics were checked simultaneously by thermogravimetric analysis (TGA). The purity of the $17{\beta}$-estradiol was 985.6 mg/g and the expanded uncertainty was 2.1 mg/g at 95% confidence. The developed method can be applied to the development of certified reference materials, which play a critical role in traceability.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.359-367
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• 2016

Background: As new legislation has come into force implementing radiation safety management for the use of naturally occurring radioactive materials (NORM), it is necessary to establish a rapid and accurate measurement technique. Measurement of $^{238}U$ and $^{232}Th$ using conventional methods encounter the most significant difficulties for pretreatment (e.g., purification, speciation, and dilution/enrichment) or require time-consuming processes. Therefore, in this study, the applicability of ED-XRF as a non-destructive and rapid screening method was validated for raw materials and by-product samples. Materials and Methods: A series of experiments was conducted to test the applicability for rapid screening of XRF measurement to determine activity of $^{238}U$ and $^{232}Th$ based on certified reference materials (e.g., soil, rock, phosphorus rock, bauxite, zircon, and coal ash) and NORM samples commercially used in Korea. Statistical methods were used to compare the analytical results of ED-XRF to those of certified values of certified reference materials (CRM) and inductively coupled plasma mass spectrometry (ICP-MS). Results and Discussion: Results of the XRF measurement for $^{238}U$ and $^{232}Th$ showed under 20% relative error and standard deviation. The results of the U-test were statistically significant except for the case of U in coal fly ash samples. In addition, analytical results of $^{238}U$ and $^{232}Th$ in the raw material and by-product samples using XRF and the analytical results of those using ICP-MS ($R^2{\geq}0.95$) were consistent with each other. Thus, the analytical results rapidly derived using ED-XRF were fairly reliable. Conclusion: Based on the validation results, it can be concluded that the ED-XRF analysis may be applied to rapid screening of radioactivities ($^{238}U$ and $^{232}Th$) in NORM samples.

• Mass Spectrometry Letters
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• 제3권2호
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• pp.58-61
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• 2012

A method based on flow injection-isotope dilution-cold vapor-inductively coupled plasma mass spectrometry (FI-IDCV-ICP/MS) has been applied to determine trace level of mercury in fly ash. $^{200}Hg$ isotopic spike was added to 0.25 g of BCR176R fly ash and then decomposed by microwave digestion procedure with acid mixture A (8 mL $HNO_3$ + 2 mL HCl + 2 mL HF) and acid mixture B (8 mL $HNO_3$ + 2 mL $HClO_4$ + 2 mL HF) for applying IDMS. Mercury cold vapor was generated by using reductant solution of 0.2% (w/w) $NaBH_4$ and 0.05% (w/w) NaOH. The measurements of n($^{200}Hg$)/n($^{202}Hg$) isotope ratio was made using a quadrupole ICP/MS system. The accuracy in this method was verified by the analysis of certified reference material (CRM) of fly ash (BCR 176R). The indicative value of Hg in BCR 176R fly ash was $1.60{\pm}0.23$ mg/kg (k = 2). The determined values of Hg in BCR 176R fly ash by the method of FI-CV-ID-ICP/MS described in this paper were $1.60{\pm}0.24$ mg/kg (k = 3.18) and the analysis results were in well agreement with the indicative value within the range of uncertainty.

• 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.

• 농업과학연구
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• 제46권2호
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• pp.315-322
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• 2019

In this study, the contents of ${\beta}$-carotene and cholesterol were evaluated in various types of agricultural and processed foods (vegetables, legume products, dairy products, and eggs). Certified reference material (CRM) with an assigned value was used for the validation of the ${\beta}$-carotene and cholesterol analytical methods. High recoveries (accuracy) of ${\beta}$-carotene (96%) and cholesterol (97%) were obtained from the quantitative analysis of the CRM, with a relative standard deviation (%) of 1.86 and 3.35% for the ${\beta}$-carotene and cholesterol, respectively. Vegetables contained relatively high concentrations of ${\beta}$-carotene (raw Toona sinensis, $1650.97{\mu}g/100g$, a raw small onion, $879.09{\mu}g/100g$, and a raw lettuce stem, $591.89{\mu}g/100g$). The ${\beta}$-carotene values in dried chickpeas ($22.94{\mu}g/100g$) and dried brown lentils ($21.98{\mu}g/100g$) were similar. The highest ${\beta}$-carotene value among the analyzed dairy products was found in banana milk ($234.21{\mu}g/100g$) while other flavored products (strawberry milk and chocolate milk) did not contain any ${\beta}$-carotene. Furthermore, ${\beta}$-carotene was not detected in goat milk and high calcium milk in this study. With regard to cholesterol among the analyzed samples, the highest cholesterol value was found in egg yolk (629.30 mg/100 g), and cooking methods (boiling and frying) had little effect on the cholesterol levels of eggs. In addition, the cholesterol content in vanilla ice cream was 28.77 mg/100 g which was the highest value among the analyzed dairy products.

• Mass Spectrometry Letters
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• 제3권2호
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• pp.54-57
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• 2012

Mass spectrometric analysis was carried out using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) for the precise and accurate determination of the isotope ratios of ultratrace levels of uranium dissolved in 3% $HNO_3$. We used the certified reference material (CRM) 112-A at a trace level of 100 pg/mL for the uranium isotopic measurement. Multiple collectors were utilized for the simultaneous measurement of uranium isotopes to reduce the signal uncertainty due to variations in the ion beam intensity over time. Mass bias correction was applied to the measured U isotopes to improve the precision and accuracy. Furthermore, elemental standard solution with certified values of platinum, iridium, gold, and thallium dissolved in 3% $HNO_3$ were analyzed to investigate the formation rates of the polyatomic ions of $Ir^{40}$ $Ar^+$, $Pt^{40}$ $Ar^+$, $Tl^{40}$ $Ar^+$, $Au^{40}$ $Ar^+$ for the concentration range of 50-400 pg/mL. Those polyatomic ions have mass-to-charge ratios in the 230-245 m/z region that it would contribute to the increase of background intensity of uranium, thorium, plutonium, and americium isotopes. The effect of the polyatomic ion interference on uranium isotope measurement has been estimated.