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Survey of ERETIC2 NMR for quantification
홍란선,황화경,김선춘,조황의,이훈주,홍진태,문동철 한국자기공명학회 2013 Journal of the Korean Magnetic Resonance Society Vol.17 No.2
The ERETIC (Electronic REference To access In vivo Concentrations)2 method is a new qNMR experimental technique to measure analytes based on the signal of the reference compound without additional hardware equipment. In this study, ERETIC2 method was validated, and we sought to identify whether it would be possible to apply this method to a specific compound analysis of metabolites in plant. The 90° pulse value (P1) and spin-lattice relaxation time (T1) of each compound were measured for ERETIC2. The 91H of 3-(trimethylsilyl) propionic-2,2,3,3-d4 acid (TSP) was used as a reference peak for ERETIC 2, and then, a suitable solvent and pulse sequence for each compound were selected. Under the NOESY-presat sequence, the relative accuracy error for quantitative analyses of primary metabolites was within the range of 5%, with the exception of glucose, which showed ≥ 55% error due to saturation. It showed excellent results for the quantification of glucose by using a 30° pulse sequence, which did not suppress the water peak. In addition, the quantitative accuracy for secondary metabolites was extremely accurate, with an error ≤5% when considering the purity of the standard sample. The ERETIC2 method showed outstanding linearity, precision, and accuracy.
홍란선,조황의,우상희,최상길,김선춘,홍진태,문동철,김동우 한국자기공명학회 2013 Journal of the Korean Magnetic Resonance Society Vol.17 No.1
For a case study of suspected paraquatintoxication, we developed a simple and rapidmethod of 1H qNMR to determine the mili-molaramount of paraquat in postmortem blood samples. There were no interfering signals from endogenouscompounds in the chemical shift of paraquat anddiquat (internal standard). The amount of sampleused ranged from 0.25 mM to 10.0 mM. Diquat,which has similar physicochemical properties withparaquat, was chosen as an internal standard. TheNMR experimental conditions, relaxation delay timeand CPMG spin-echo pulse sequence were optimized. The developed method was validated in terms ofspecificity, accuracy, precision, matrix effect,recovery, limit of detection (LOD), and low limit ofquantification (LLOQ). The proposed qNMR methodprovided a simple and rapid assay for theidentification and quantification of the quaternaryammonium herbicide, “paraquat” in postmortemblood samples. This method was tested by using theblood from the heart of a man who was intoxicatedwith paraquat. In this particular case, the level ofparaquat was 1.07 mM in the blood. For thedetermination of quaternary ammonium herbicides,qNMR could also be used to provide a betterunderstanding of the currently available techniques.
전영화,홍란선,강영진,강성주,Jeon, Yeong-Hwa,Hong, Lan-Sun,Kang, Young-Jin,Kang, Seong-Joo 대한화학회 2004 대한화학회지 Vol.48 No.2
이 연구에서는 산-염기 중화반응의 실험 방법에 관련된 과학 교과서 내용을 분석하고, 문제점을 개선하는데 목적이 있다. NaOH-HCl 수용액의 중화반응실험에서 1) 페놀프탈레인의 decoloration, 2) 염 생성 확인을 위해 적정된 용액의 농축을 위한 가열 과정에서의 색 변화, 3) 염 결정 확인의 어려움이 문제점으로 지적되었다. 이러한 문제점들은 페놀프탈레인의 구조변화에 근거하여 설명하였고, 개선된 실험방법을 제시하였다. The aim of this study is to analyze and improve the experiment of the acid-base neutralization reaction described in science textbooks. The problems in the neutralization reaction of NaOH-HCl solution were following; 1) the decoloration of phenolphthalein solution, 2) the color change of the titrated solution during condensation for the confirmation of the salt crystals, 3) the difficulty for the confirmation of the salt crystals. These problems are explained by the structure change of phenolphthalein and the improved experiment is proposed.