임상진단검사에서의 분석과학

이화심 한국분석과학회 2017 학술대회논문집 Vol.2017 No.5

동위원소 희석 HPLC/MS에 의한 혈청 내 urea의 정량

이화심,박상열 한국분석과학회 2005 분석과학 Vol.18 No.4

산성비의 pH 측정에 대한 연구

이화심,김명수,Lee, Hwa-Shim,Kim, Myung-Soo 대한화학회 2000 대한화학회지 Vol.44 No.1

일반적으로 산성비는 이온세기가 낮아 저항이 크고 완충능이 없는 용액이다. 그러므로 산성비의 pH측정 시, 시료용액의 액간접촉전위는 이온세기의 차이로 인해 pH표준용액의 액간접촉전위와 달라서 pH 측정값에 오차가 발생될 수 있다. 실제 1998년도 대덕연구단지에 내린 빗물의 평균 전도도 값이 12.8 ${\mu}S/cm$인데 비해, pH 표준용액의 전도도 값은 약 5,980 ${\mu}S/cm$으로 이온세기의 차이가 크다. 본 연구에서는 산성비의 pH를 측정할 때 액간접촉전위로 인해 발생되는 오차를 보정하기 위해, 빗물과 비슷한 pH와 전도도를 가지는 묽은 황산의 물성조절표준물(Quality Control Standard, 이하 QCS로 표기)을 제조하여 사용하였다. QCS의 pH값을 액간접합이 없는 수소전극 시스템으로 인증한 다음, 유리전극으로 다시 pH를 측정하여 그 차이값 만큼 보정하였다. 아울려 이 방법으로 1998년도 대덕연구단지에 내린 빗물의 pH를 측정하였다. In general, acid rain is unbuffered solution with low ionic strength and high resistance. Therefore during the pH measurement of acid rain, error can be occurred due to the liquid junction potential difference between the sample and the standard solution. Actually the average conductivity of rain in Taeduk Science Town during 1998 is 12.8 ${\mu}S/cm$, while that of pH standmd solutions is about 5,980 ${\mu}S/cm$. There is a large difference in ionic strength. To compensate the bias due to residual liquid junction potentials, a quality control standard(QCS) of dilute sulfuric acid, which has the conductivity and pH values simikw to rain, was prepared. The pH of QCS solution was determined using the hydrogen electrode system without liquid junction, and compensation has been made for the bias terms by performing the pH measurements with glass electrode. On the basis of this compensation method, the pH vaiues of rain in Taeduk Science Town during 1998 were measured.

Purity assignment of 17β-estradiol by mass balance method

이화심,오광훈 한국분석과학회 2017 분석과학 Vol.30 No.5

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 17β-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 17β-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 17β- 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.

Development and Validation of Primary Method for the Determination of Glucose in Human Serum by Isotope Dilution Liquid Chromatography Tandem Mass Spectrometry and Comparison with Field Methods

이화심,이종만,박상열,이제훈,김용구 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

Glucose is a common medical analyte measuring in human serum or blood samples. The development of a primary method is necessary for the establishment of traceability in measurements. We have developed an isotope dilution liquid chromatography tandem mass spectrometry as a primary method for the measurement of glucose in human serum. Glucose and glucose-13C6 in sample were ionized in ESI negative mode and monitored at mass transfers of m/z 179/89 and 185/92 in MRM, respectively. Glucose was separated on NH2P- 50 2D column, and the mobile phase was 20 mM NH4OAc in 30% acetonitrile/70% water. Verification of this method was performed by the comparison with NIST SRMs. Our results agreed well with the SRM values. We have developed two levels of glucose serum certified reference material using this method and distributed them to the clinical laboratories in Korea as samples for proficiency testings. The expended uncertainty was about 1.2% on 95% confidence level. In proficiency testings, the results obtained from the clinical laboratories showed about 3.6% and 3.9% RSD to the certified values. Primary method can provide the traceability to the field laboratories through proficiency testings or certified reference materials.

우울증 아내를 돌보는 중년 남성의 심리적 경험 연구

이화심,김병오 한국상담학회 2018 상담학연구 Vol.19 No.6

본 연구는 우울증 아내를 돌보는 중년 남성의 심리적 현상의 본질이 무엇인지를 밝히고자 하는 연구이다. 이를 위해 본 연구는 우울증 아내를 돌보고 있는 중년 남성 8명을 대상으로 심층 면담을 하였다. 심층 면담한 자료를 근거로 Colaizzi의 현상학적 연구방법으로 분석한 결과 구성의미 116개, 주제 37개, 주제군 12개를 도출하였다. 도출된 결과에 의하면 중년 남성은 우울증 아내를 돌보면서 ‘자신의 역할 부족에 대한 죄책감’, ‘다중 역할로 인한 긴장’, ‘돌봄의 한계에서 오는 고갈 상태’ 등의 심리적 고통을 받는 것으로 밝혀졌다. 또한, 돌봄의 시간이 지속될수록 끝을 예측할 수 없는 ‘불확실한 미래로 인한 낙담’으로 인해 고통스러워하는 것으로 밝혀졌다. 이들은 돌봄의 고통으로 인해 돌봄 상황을 회피하기도 했지만, 가족에 대한 책임감으로 돌봄의 현실을 수용하고 가족과 직장동료 등 주변인들의 격려에 힘을 얻으며 돌봄을 지속하는 것으로 나타났다. 이로써 본 연구는 우울증 아내를 돌보는 중년 남성들의 내적 심리를 심층적으로 탐색하고 드러냄으로써 우울증 아내를 돌보고 있는 중년 남성들을 위한 상담적 개입 방안의 자료를 제공하는 데 의의를 지닌다. This study is intended to find out the nature of the psychological phenomenon of middle-aged men who care for their wives with depression. To do this, in-depth interviews were carried out with eight middle-aged spouses caring for their depressed wives. Based on the interviews, 116 formulated meanings, 37 themes and 12 theme clusters were classified by the Colaizzi’s descriptive phenomenological method. This result reveals that middle-aged men who were taking care of their own wives with depression experienced psychological pain, such as ‘feeling of guilty for his insufficient role’, ‘tensity from the multiple roles’, and ‘exhaustion from limited roles in caring’. As time goes by, those husbands suffered a severe pain due to the uncertain future that could not predict the end of care. Even though they tried to avoid the circumstances for a while, with the sense of responsibility for their families and encouragement from the surrounding people such as family, colleagues, they finally accepted the situation and continued to care their spouses. This study is meaningful in providing data on counseling interventions for middle-aged men who are caring for their depressed wives by depth exploring and revealing the inner psychology of middle-aged men.

pH 측정 시스템의 표준화에 관한 연구

이화심,김명수,김진복,오상협,Lee, Hwa Shim,Kim, Myung Soo,Kim, Jin Bok,Oh, Sang Hyup 대한화학회 1998 대한화학회지 Vol.42 No.4

Since the definition of pH, $pH=-Ioga_H$ is based on a single ion activity, pH values can not be determined with measurement itself, but require an approximation method. They are derived from EMF measurement of a liquid junction free cell using hydrogen and Ag/AgCl electrodes. Primary standard materials with certified pH values can be obtained with this approximation method. Standard buffer solutions are used to calibrate pH meters. Thus the accuracy of the pH values of standard buffer solutions limits the reliability of measured pH values can be obtained with this approximation method. Standard buffer solution are used to calibrate pH meters. Thus the accuracy of the pH values of standard buffer solutions limits the reliability of measured pH values of sample solutions. To certify the pH values, we have established the system for the primary standard measurement and certified the pH of buffer solutions in the range of 1.6∼12.5 pH unit within uncertainty of ${\pm}0.005$ pH unit. $pH=-loga_H$ 정의에서 pH는 단일 이온의 활동도항을 포함하므로 단지 측정의 방법만으로는 결정되어질 수 없고 근사법을 필요로 한다. 근사법에 의한 pH 측정은 수소전극과 은/염화은 전극을 사용한 액간 접촉이 없는 cell의 기전력 측정으로부터 이루어지는 방법이며, 이 과정을 통해 pH 값이 인증된 pH의 일차 표준 물질을 얻을 수 있다. 일반적인 pH 미터와 전극을 검정하는 데에는 인증된 pH 값을 가지는 표준 완충용액을 사용하므로 표준 완충용액의 pH 값 정혹도는 실제 측정된 pH 값의 실효성을 제한할 수 있다. 본 연구에서는 정확한 pH의 측정을 위해서 pH 값을 인증할 수 있는 시스템을 구축하기 위한 제반의 연구를 수행하였으며, 이를 토대로 pH 1.6∼12.5의 범위에 해당하는 완충용액의 pH를 0.005 pH 단위 이내의 불확도로 인증하였다.

진단검사 신뢰성과 측정표준

이화심 한국환경분석학회 2013 제1회 한국분석기술단체 총 연합 합동 심포지엄 Vol.0 No.-

Method Development for Purity Assignment of l-Valine by a Mass Balance Method

이화심,Su Jin Park,Eun Jeong Ahn,김숙경,Gae Ho Lee,Myungsoo Kim 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.3

Measurement of Cortisol in Human Serum by Isotope Dilution Liquid Chromatography/Mass Spectrometry and a Comparison through a Proficiency Testing

이화심,Hyesun Shin,박상열,Chang Joon Park 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.5

Liquid chromatography/mass spectrometry using isotope dilution method has been established as a primary method for the measurement of cortisol in human serum. Verification of this method was accomplished by the participation in Consultative Committee for Amount of Substance-Metrology in Chemistry (CCQM) pilot study. Two levels of cortisol certified reference materials were prepared and certified by the established method. They were used as sample materials for the proficiency testing. The expanded uncertainty in the measurement of cortisol in human serum was approximately 1.2% at 95% confidence level. The results of the proficiency testing showed a good precision among the participants,but some bias to the certified values. This means that commercial field laboratories should keep traceability chain to SI unit through available reference measurement procedures and/or available reference materials.