• 한국식품영양과학회지
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• 제30권4호
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• pp.726-731
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• 2001

밤 가공공장에서 폐기되고 있는 밤의 귀피를 항산화 기능성 자원으로 활용하고자 밤 귀치의 methanol 추출물 및 용매획분을 benzoic acid 수산화법으로 hydroxyl radical 소거능과 ferric thiocyanate법으로 과산화물생성 억제능을 시험하였다. 대부분의 획분에서 항산화성을 보였으며 특히 ethyl acetate 획분에서 BHA나 $\alpha$-tocopherol과 거의 유사한 rkdgkshydroxyl radical 소거능과 지질과산화물생성 억제능을 보였다. Ethyl acetate 획분으로부터 항산화성 물질을 분리하기 위하여 Sephadex LH-20 column chromatography 및 prep HPLC를 행하여 단일 물질로 정제하였다. 분리 정제된 물질을 $^{1}$H-NMR과 $^{13}$C-NMR로 구조 분석한 결과 gallic acid로 동정하였다. 페놀산을 GC로 분석한 결과 밤 귀피의 주요 페놀산으로 ellagic acid(172.22 mg%) 와 gallic acid(107.39 mg%)가 확인되었다.

• Environmental Engineering Research
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• 제17권4호
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• pp.205-210
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• 2012

Hydroperoxyl radical/superoxide anion radical ($HO_2{\cdot}/O_2^-{\cdot}$, $pK_a$=4.8) as an intermediate is of considerable importance in oxidation processes. Hence, the method of detecting $HO_2{\cdot}/O_2^-{\cdot}$ with high sensitivity is necessary to be developed. To achieve this objective, this study newly employed terephthalate (TA) as a probe for the measurement of $HO_2{\cdot}/O_2^-{\cdot}$ in the kinetic method presented in our previous study. This method was based on the hydroxylation of TA to produce mainly hydroxyterephthalic acid or hydroxyterephthalate (OHTA), which was analyzed by fluorescence detection (${\lambda}_{ex}$=315nm, ${\lambda}_{ex}$=425nm). The life-time of $HO_2{\cdot}/O_2^-{\cdot}$ and its concentration formed from the photolysis technique of $H_2O_2$ were reported in this study. At range of pH 2-10, the life-time of $HO_2{\cdot}/O_2^-{\cdot}$ was 51-422 sec. In particular, an increase in the life-time with pH was observed. The sensitivities of the kinetic method by using TA were always higher with 1.7-2.5 times at pH 8.0 than those by using benzoic acid. From these results, this study can contribute to understanding the basic functions of $HO_2{\cdot}/O_2^-{\cdot}$ in oxidation processes.

• Journal of Korean Society for Atmospheric Environment
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• 제23권E1호
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• pp.16-28
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• 2007

An improved method was developed to determine gas-phase hydrogen peroxide($H_2O_2$) and organic hydro-peroxides (ROOH) in real-time, The analytical system for $H_2O_2$ is based on formation of hydroxybenzoic acid (OHBA), a strong fluorescent compound. OHBA is formed by a sequence of reactions, photoreduction of Fe(III)-EDTA to Fe(II)-EDTA, the Fenton reaction of Fe(II)-EDTA with $H_2O_2$, and hydroxylation of benzoic acid. By use of this analytical method rather than a previous similar method, Fenton reaction time was reduced from 2 min. to 30s. Air samples were collected by a surfaceless inlet to prevent inlet line losses. With a special arrangement of the sampling apparatus, sample delivery time was drastically reduced from ${\sim}5\;min\;to\;{\sim}20\;s$. The automated system was found to be sensitive, capable of continuous monitoring, and affordable to operate. A comparison of this method with a well-established one showed an excellent linear correlation, validating applicability of this technique to $H_2O_2$ determination. The system was applied to field measurements conducted during summertime of 2004 in Gwangju, South Korea. $H_2O_2$ was found to be a predominant species of peroxides. The diurnal variation of $H_2O_2$ displayed the maximum in early afternoon and the broad minimum throughout night. $H_2O_2$ was correlated positively with ozone, photochemical age, and temperature, however, negatively with $NO_x$ and relative humidity.