• Mass Spectrometry Letters
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• 제5권2호
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• pp.57-61
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• 2014

A gravimetric standard addition method combined with internal standard calibration has been successfully developed for the accurate analysis of total arsenic in a laver candidate reference material. A model equation for the gravimetric standard addition approach using an internal standard was derived to determine arsenic content in samples. Handlings of samples, As standard and internal standard were carried out gravimetrically to avoid larger uncertainty and variability involved in the volumetric preparation. Germanium was selected as the internal standard because of its close mass to the arsenic to minimize mass-dependent bias in mass spectrometer. The ion signal ratios of $^{75}As^+$ to $^{72}Ge^+$ (or $^{73}Ge^+$) were measured in high resolution mode ($R{\geq}10,000$) to separate potential isobaric interferences by high resolution ICP/MS. For method validation, the developed method was applied to the analysis of arsenic content in the NMIJ 7402-a codfish certified reference material (CRM) and the result was $37.07mg{\cdot}kg^{-1}{\pm}0.45mg{\cdot}kg^{-1}$ which is in good agreement with the certified value, $36.7mg{\cdot}kg^{-1}{\pm}1.8mg{\cdot}kg^{-1}$. Finally, the certified value of the total arsenic in the candidate laver CRM was determined to be $47.15mg{\cdot}kg^{-1}{\pm}1.32mg{\cdot}kg^{-1}$ (k = 2.8 for 95% confidence level) which is an excellent result for arsenic measurement with only 2.8 % of relative expanded uncertainty.

• Mass Spectrometry Letters
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• 제4권4호
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• pp.75-78
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• 2013

A gas chromatography/mass spectrometric (GC/MS) method was developed as a candidate reference method for the accurate determination of essential fatty acids (linoleic acid, ${\alpha}$- and ${\gamma}$-linolenic acids) in food supplemental oil products. Samples were spiked with three internal standards (stearic acid-$d_{35}$, $^{13}C_{18}$-linoleic acid, and $^{13}C_{18}$-${\alpha}$-linolenic acid). Samples were then subject to saponification, derivatization for methylation, and extraction by organic solvent. For GC/MS measurement, an Agilent HP-88 column, designed for the separation of fatty acid methyl esters, was selected after comparing with other columns as it provided better separation for target analytes. Target analytes and internal standards were detected by selected ion monitoring of molecular ions of their methyl ester forms. The GC/MS method was applied for the measurement of three botanical oils in NIST SRM 3274 (borage oil, evening primrose oil, and flax oil), and measurement results agreed with the certified values. Measurement results for target analytes which have corresponding isotope-labeled analogues as internal standard were calculated based on isotope dilution mass spectrometry (IDMS) approach, and compared with results calculated by using the other two internal standards. Results from the IDMS approach and the typical internal standard approach were in good agreement within their measurement uncertainties. It proves that the developed GC/MS method can provide similar metrological quality with IDMS methods for the measurement of fatty acids in natural oil samples if a proper fatty acid is used as an internal standard.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.299-303
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• 2016

Prompt gamma activation analysis using a thermal neutron-guided beam at Japan Atomic Energy Agency JRR-3M was applied for the precise determination of Si in silicon nitride ceramic reference materials [Japan Ceramic Reference Material (JCRM) R 003]. In this study, the standard addition method coupled with internal standard was used for the nondestructive determination of Si in the sample. Cadmium was used as internal standard to obtain the linear calibration curves and to compensate for the neutron beam variability. The analytical result of determining Si in JCRM R 003 silicon nitride fine powder ceramic reference materials using prompt gamma activation analysis was in good agreement with that obtained by classical gravimetric analysis. The relative expanded measurement uncertainty (k = 2) associated with the determined value was 2.4%.

• Applied Microscopy
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• 제29권1호
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• pp.75-81
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• 1999

본 실험에서 얻어진 결론을 요약하면 아래와 같다. (1) 저진공도의 sputter coater를 이용하여 Au 내부 표준시편을 제작하는 최적 조건은 9mA의 전류로 100 초간 coating하는 것이다. (2) 고진공도의 evaporation coater를 이용하여 Al 내부 표준시편을 제작하는 최적 조건은 7kV의 전압으로 10분간 coating하는 것이다. (3) Au 내부 표준시편을 이용하여 측정한 홍주석 격자상수 값의 측정오차는 정밀도가 1.2% 이하이고, 정확도는 0.3% 이하이다. (4) Au 내부 표준시편을 이용하여 측정한 알바이트 장석 격자상수 값의 측정오차는 정밀도가 0.5% 이하이고, 정확도는 1.1% 이하이다. (5) 내부 표준시편을 사용하여 격자상수를 측정할 때 가장 심각한 오차는 전자회절도형의 거리 및 각도 측정시 발생한다. 체계적인 측정 방법과 정밀도 높은 측정 도구의 사용이 필요하다. (6) 시료나 TEM 조건 때문에 분말 XRD 방법이나 수렴성빔 전자회절법으로 격자상수를 구할 수 없는 경우에는 내부 표준시편을 이용한 TEM 격자상수 측정법이 좋은 대안이 된다.

• 한국간호교육학회지
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• 제23권4호
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• pp.378-388
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• 2017

Purpose: The aim of this study was to identify the status of performance on standard precautions among nursing students and to examine the mediating effects of internal health locus of control on the relationship between awareness and performance on standard precautions of hospital-acquired infection control. Methods: The participants in this study were 134 nursing students. The measurements included a standard precautions awareness and performance scale, and a multidimensional health locus of control scale. Data were analyzed using independent t-test, one-way ANOVA, $Scheff{\acute{e}}$ test, Pearson correlation coefficient, and simple and multiple regression techniques. Mediation analysis was performed by the Baron and Kenny's method and Sobel test. Results: The mean score of standard awareness, standard performance, and internal health locus of control about standard precaution were $174.30{\pm}9.08$; $169.48{\pm}12.04$; and $20.43{\pm}2.82$; respectively. There was a positive correlation between standard awareness and performance (r=.414, p<.001). Also, standard awareness was significantly correlated with internal health locus of control (r=.413, p=.014). Internal health locus of control showed partial mediating effects in the relationship between awareness and performance. Conclusion: The results indicate a need to improve the internal health locus of control of nursing students. Therefore, an internal health locus of control improvement program should improve performance on standard precautions for patients and themselves.

• BMB Reports
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• 제29권5호
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• pp.481-483
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• 1996

In competitive PCR, which is used to quantify target DNA an internal standard is needed. Here we present a simple method to construct homologous competitive standards. The method, which is based upon deletion of a portion of the target DNA, does not require any additional primers. This is the simplest method developed thus far to construct a competitive standard. The whole procedure. from construction of a competitive standard to quantitation by PCR, can be completed within a single day.

• Mass Spectrometry Letters
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• 제9권3호
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• pp.77-80
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• 2018

The focus of this paper is to present techniques to overcome certain difficulties in quantitative analysis with a time-of-flight mass spectrometer (TOF-MS). The method is based on conventional solid-phase extraction, followed by reversed-phase ultra high performance liquid chromatography of the extract, and mass spectrometric analysis. The target compounds included atenolol, atrazine, caffeine, carbamazepine, diclofenac, estrone, ibuprofen, naproxen, simazine, sucralose, sulfamethoxazole, and triclosan. The matrix effects caused by high concentrations of organic compounds in wastewater are especially significant in electrospray ionization mass spectroscopy. Internal-standard calibration with isotopically labeled standards corrects the results for many matrix effects, but some peculiarities were observed. The problems encountered in quantitation of carbamazepine and triclosan, due to nonlinear calibration were solved by changing the internal standard and using a narrower mass window. With simazine, the use of a quadratic calibration curve was the best solution.

• 분석과학
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• 제23권1호
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• pp.24-35
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• 2010

본 연구에서는 GC-PFPD와 열탈착 분석기법을 이용한 환원 황화합물(reduced sulfur compounds: RSC)에 대한 열탈착 검량방식의 시간적 재현성을 기존의 외부 검량기법에 덧붙여, 내부표준시료 기법을 연계하여 평가하고자 하였다. 이를 위하여, 4종류의 악취성 황화합물질($H_2S$, $CH_3SH$, DMS, DMDS)과 이들에 대한 내부 표준시료로 CS2를 준비하였다. 이들 표준시료는 저농도(10, 20, 50, 100 ppb)와 고농도 그룹(100, 200, 500, 1000 ppb)을 대표할 수 있게 넓은 범위로 준비하였다. 그리고 외부검량(external calibration)방식의 분석 결과를 부피고정방식(fixed standard volume: FSV)과 농도고정방식(fixed standard concentration: FSC)로 비교하였다. 또한, 2차적으로 FSV 방식의 결과에 외부 및 내부 검량기법을 동시에 적용하여 검량방식의 경시변화(안정도)를 평가하였다. 본 실험의 결과, 감도에 대한 경시변화는 FSC 방식에 비해 FSV 방식에서 작게 나타났다. 따라서 RSC 분석에서 FSV방식이 경시변화를 줄여주는데 상대적으로 효과적이라는 것을 알 수 있었다. 2차적으로 FSV 방식의 결과에 대해 외부 및 내부방식의 감도(기울기 값)를 비교하였다. 이러한 비교를 상대표준편차(RSD)값으로 평가하면, GC-PFPD-TD 시스템의 감도가 비교적 강한 경시변화를 보인다는 것을 알 수 있다. 따라서 이러한 분석기법의 시간적 재현성을 확보하기 위해서는 여러 가지 검정노력이 필요한 것으로 사료된다.

• 동의생리병리학회지
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• 제26권3호
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• pp.367-375
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• 2012

The goal of current study is to make a standard pattern identification for post stroke depression using a delphi method. Finally, ten experts of oriental medicine, especially of stroke or depression, participated in Dephi examination. At the first meeting, experts conducted free discussion and determined to use the previous published questionnaires of Deficiency-Excess identification and Cold-Heat identification. From the second round, experts participated in evaluating and correcting the questionnaire by email. New seven questions were added to the questionnaire of Deficiency-Excess identification through the second round. Finally, the standard pattern identification of Cold-Heat or Deficiency-Excess is composed 20 questions and 11 questions, respectively. These pattern identifications for post stroke depression will contribute to research and treatment of oriental medicine.

• 한국식품과학회지
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• 제43권5호
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• pp.532-536
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• 2011

본 연구에서는 IC-MS/MS 시스템에 내부표준물질($^{35}Cl^{18}O_4^-$)을 이용하여 식품에서의 정확한 perchlorate 분석을 위한 최적화된 전처리 방법을 제시하였다. Perchlorate를 분석하기 위한 식품의 전처리는 미국 FDA에서 제안하는 perchlorate 분석을 위한 식품 전처리 방법을 변형하여 더욱 재현성이 높은 방법을 제시하였으며, 제시된 분석법의 신뢰성을 검증하기 위한 유효성의 검토는 음용수, 우유 및 분유, 쌀, 채소류, 해조류 등 다양한 식품들을 대상으로 MDL과 LOQ를 설정하여 외국의 사례와 비교 확인하였다. 또한 시료에 표준물질을 첨가하여 회수율 및 재현성을 확인하였다. 본 연구에서 수행된 5 ${\mu}g/L$ 및 5, 10 ${\mu}g/kg$의 perchlorate 회수율 시험 결과 모든 시료에서 %RSD는 적합범위(<20%) 내에 포함되었고 평균 %RSD는 6.4%로 나타났으며, %Recovery도 98-105%로 적합한(80% < x < 120%) 범위로 나타났다. 따라서 본 연구에서 제시한 정확한 perchlorate 분석을 위한 식품 시료의 전처리 방법은 반복 분석을 통한 시험의 정확도 및 재현성을 확인할 수 있었으며, 향후 다른 식품에 대한 perchlorate 분석에도 적용하여 관련분야 연구에 크게 기여할 것으로 기대된다.