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        검색결과 5

        1.
        2023.11 구독 인증기관·개인회원 무료
        This study demonstrated a rapid and simple method for the determination of seven anions including halides and oxyhalides from the KURT underground water sample by capillary electrophoresis with UV detection. In nuclear waste disposal, some anions such as iodine, selenium, and technetium have been of great concern due to its high mobility and toxicity with a long half-life. It has been needed for a reliable analysis of anionic speciation because the high mobility of anions is easily affected by environmental conditions especially pH and salinity of underground water. Here this project is to develop a fast separation of seven anions including iodide, iodate, and selenite using capillary electrophoresis. The electroosmotic flow (EOF) was suppressed using a poly (ethyleneglycol) -coated capillary (DB-WAX capillary). As a result, anions migrated depending on their mobility under a reverse polarity condition (-15 kV) and the analysis time was within 15 min. UV detection was used at 200 nm. The RSDs for migration time were between 0.7% and 1.3% except for selenite of 5.1%. The RSDs for peak area were obtained between 2.9% and 7.4%. The calibration curves were linear from 10 to 200 mg/L with correlation coefficients greater than 0.9952. The LODs were 7.3, 10.9, 11.3, 12.9, 13.0, 13.9, and 17.4 mg/L for iodide, nitrate, bromide, selenite, bromate, tungstate and iodate. The KURT underground water sample spiked with seven anions at 50 mg/L were analyzed. The recoveries of spiked KURT sample ranged from 93.4% to 99.3%. The proposed method was successfully applied to determine seven anions in underground water sample.
        2.
        2017.12 구독 인증기관 무료, 개인회원 유료
        A novel method for the detection of hydrogen peroxide in aqueous solution was developed via reaction between H2O2, trivalent titanium ion (Ti3+) and 4-(2-thiazolylazo) resorcinol (TAR), resulting in a ternary complex with a maximum UV absorbance at 530 nm. The CE detection of H2O2 was fast, sensitive and cost-effective without pretreatment procedures. H2O2 was detected within 15 min at 1 to 100 μM range with the lowest detection limit at 1.0 μM. Under the optimized CE conditions, the concentration of H2O2 in coffee or tea extract was quantitatively determined. Our results show that CE detection of the ternary complex of H2O2-Ti3+-TAR has potential applications for the detection of H2O2 in aqueous sources.
        4,000원
        5.
        2003.04 서비스 종료(열람 제한)
        Higenamine [1-(4-hydroxy-6, 7-dihydroxy-l, 2, 3, 4-tetrahydroisoquinoline) is a cardiotonic constituent of Aconiti tuber, one of the most widely prescribed oriental medicines. S-(-)higenamine was reported to have a stronger cardiotonic activity than R-(+)-higenamine and known as a central intermediate in the biosynthesis of various benzyl isoquionoline alkaloids in plants. The separation of higenamine enantiomers has been accomplished with capillary electrophoresis using cyclodextrins (CDs) as chiral selectors. Good resolution of this enantiomers was obtained using a 50 mM sodium phosphate buffer containing hydroxypropyl β-CDs using 27 cm fused silica capillary (50μm i.d., 20 cm to detector) at 25 ℃. With the electric field of 340 V/cm, the separation time of higenamine enantiomers was less than 6 min. Under this optimum conditions, the relative standard deviations of migration time and peak area were less than 1.6% and 3.2%. A 512-channel diode array detector was confirmed for the higenamine. The detection limits (S/N = 3) of these enantiomers are 1.5mutextrmm/mL. We confirmed the chiral form of higenamine in medicinal plants.