• 분석과학
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• 제29권4호
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• pp.202-208
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• 2016

A novel and simple method for detecting seven organic acids (formic acid, malic acid, lactic acid, acetic acid, citric acid, fumaric acid and propionic acid) in animal feed using high performance liquid chromatography equipped with a photo-diode array detector (HPLC/PDA) was developed. The chromatographic peaks of the seven organic acids were successfully identified by comparing their retention times and UV spectra with reference standards. Method validation was performed in terms of linearity, sensitivity, selectivity, accuracy, and precision. The limits of detection (LODs) for the instrument employed in these experiments ranged from 12 to 8,026 μg/kg, and the limits of quantification (LOQs) ranged from 43 to 26,755 μg/kg. Average recoveries of the seven organic acids ranged from 79.3 to 95.2 %. Method replication resulted in intra- day and inter-day peak area variation of <3.2 %. The developed method was specific and reliable and is therefore suitable for the routine analysis of organic acids in animal feed.

• 한국산업보건학회지
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• 제9권1호
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• pp.23-40
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• 1999

The analysis of thiodiglycolic acid in urine has been used as an index of biological exposure to vinyl chloride. Unfortunately thiodiglycolic acid has a strong hydrophilic character, because it has two carboxylic groups, so that it can only be extracted with organic solvent with a great difficulty. Underivatized thiodiglycolic acid tends to tail because of non-specific interaction with the inert support. Therefore, esterification is the obvious first choice for derivatization of thiodiglycolic acid, particularly for gas chromatography. In this study, the focus of interest is to compare two method of esterifications (methylation and silylation). Methylation is to make the methyl ester of thiodiglycolic acid by reaction with diazomethane. Silylation is to make the trimethylsilyl ester of thiodiglycolic acid by reaction with N-trimethylsily-ldiethylamine. The results and conclusions are as the following: 1. The detection limit (sensitivity) of methylated thiodiglycolic acid was $5.00{\mu}g/m{\ell}$ and silylated thiodiglycolic acid was $3.07{\mu}g/m{\ell}$ by gas chromatography with flame ionization detector. 2. The optimal liquid-liquid extraction of thiodiglycolic acid was as following: To each of the tubes, $15m{\ell}$ of urine, concentrated sulfuric acid (pH 1 - 2) and 5 gsodium sulfate were added. The samples was extracted three times with $5m{\ell}$ ethylacetate each time. 3. The methylated thiodiglycolic acid was more stable than silylated thiodiglycolic acid in extractional solvent which contained humidity. 4. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.07324 in methylated thiodiglycolic acid with external standard calibration, and 0.07033 in methylated thiodiglycolic acid with internal standard calibration. 5. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.10914 in silylated thiodiglycolic acid with external standard calibration, and 0.13602 in silylated thiodiglycolic acid with internal standard calibration. From the above results, the analysis of methylated thiodiglycolic acid was more sensitive (limit of detection) than silylated thiodiglycolic acid by gas chromatography. However, the methylated thiodiglycolic acid was stable in the humidity and was separated sharply on chromatogram. Also, analysis of methylated thiodiglycolic acid was more precise (pooled coefficient of variation for 4 days) than silylated thiodiglycolic acid. In conclusion, it is established that the analysis of methylated thiodiglycolic acid is appropriate for biological monitoring of exposure to vinyl chloride.

• 약학회지
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• 제13권2_3호
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• pp.84-87
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• 1969

Microanalysis of organic sulfur compounds by means of combining thin layer chromatography and oxygen combustion flask method was attempted. The following procedure was found to be very simple and to give accurate results. The mixture of sulfa drugs was separated with T.L.C., and it was burned in a flask filled with oxygen, and the gas formed was absorbed in a dilute solution of sodium hydroxide. The solution was neuralized with hydrochloric acid and heated in a water bath. The sulfate ion formed was then treated with barium chromate solution and its absorbancy at 370 m.mu. was measured.

• 펄프종이기술
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• 제46권3호
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• pp.37-43
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• 2014

Kinetics of holocellulose hydrolysis in concentrated sulfuric acid was analyzed using $^1H$-NMR spectroscopy with different reaction time, temperature and acid concentration in secondary hydrolysis. In this work, reaction condition of secondary hydrolysis was similar to concentrated sulfuric acid process with electrodialysis or simulated moving bed chromatography process for sulfuric acid recycling. By $^1H$-NMR spectroscopy, acid hydrolyzates from higher secondary acid hydrolysis (25-35% acid concentration) was successfully analyzed without any difficulties in neutralization or adsorption of acid hydrolyzate to solid salt. Higher acid concentration, higher temperature and longer reaction time led to more cellulose for glucose conversion but accompanied with glucose to galactose isomerization, glucose to unknown compounds and degradation of glucose to organic acid via furans.

• Clinical and Experimental Pediatrics
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• 제49권3호
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• pp.258-267
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• 2006

목 적 : 국내의 유기산 대사 이상 질환들의 상대적 발병 빈도와 임상양상을 알아보기 위하여 유기산 정량 분석이 가능하여진 1997년 7월부터 2005년 5월까지 8년간 전국에 있는 대학병원에서 의뢰된 1,787명의 환자의 검체를 분석한 결과를 3년 전 발표한 연구결과와 비교하여 정리하였다. 방 법 : 1997년 7월 1일부터 2005년 5월 31일까지 약 8년 동안 본원 임상유전학연구실로 분석이 의뢰되었던 1,787명 환자의 검체들의 분석결과를 신생아기(생후 2개월까지), 영아기(2개월 이후 2세까지), 유소아기(2세 이후 12 세까지) 및 청소년기 이후(12세 이후)로 분류하였고, 환자들의 주요증상 및 소견을 분류하였다. 유기산 분석은 83종의 유기산을 gas chromatography와 mass spectrometry를 이용하여 정량 분석하였으며, 특징적인 양상으로 진단하였다. 결 과 : 총 28가지 질환 470명의 환자를 이 기간 동안에 진단할 수 있었으며, 가장 빈도가 높았던 질환들은 cytosolic 3-ketothiolase 결핍증, 사립체의 호흡 연쇄 효소의 이상 질환군(mitochondrial respiratory chain disorders), PDHC 결핍증, mitochondrial 3-ketothiolase 결핍증, glutaric aciduria type II biotinidase 결핍증, 메틸말론산뇨증(methylmalonic aciduria), 프로피온산뇨증(propionic aciduria) 등이었다. 결 론 : 유기산 대사 장애 질환들은 각각의 발병 빈도는 낮으나 국내에서도 다양한 질환들이 발병되고 있으며, 이들 질환들은 대부분의 경우 신경학적 이상 소견을 보이고 있으므로 신경학적 이상 소견을 보이는 경우는 감별진단에 포함시켜야 된다. 3년전 Choi 등이 발표한 연구결과와 비교하여 새로운 질환의 출현은 없었고 빈도가 높은 질환의 발병빈도의 차이도 보이지 않았다. 3년 전의 연구당시 짧은 연구기간으로 인한 오차의 가능성을 염려하였으나 8년 동안의 긴 연구기간 동안 비슷한 상대적 발병빈도를 보여 이러한 질환들이 우리나라에서 다수 발병되는 것으로 판단되며 주의가 필요하다고 판단된다.

• 치위생과학회지
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• 제19권1호
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• pp.1-8
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• 2019

Background: Erosion is a gradual process that occurs fairly quickly, and the full extent of the erosive effects of acidic beverages is not yet clear. The present study aimed to determine the differences in the erosive potentials among four naturally acidic fruit nectars within the same range of titratable acidity and to determine the influence of the components of organic acids on tooth erosion. Methods: Diluted fruit nectars (mandarin 1:1.1, orange 1:1.7, lemon 1:15, grapefruit 1:20) with the same range of titratable acidity (7.9 ml) and their corresponding organic acids (0.05%, 0.1%, 0.3%, and 0.5% citric acid, malic acid, and a citric and malic acid mixture [pH 2.8], respectively) were used. Specimens were placed in conical tubes with 50 ml of each of the test solutions for 1 hour. A microhardness test and scanning electron microscopy were used to measure enamel erosion. Acid separation was carried out using high-performance liquid chromatography to analyze the composition of each test solution. Results: Similar decreases in the Vickers hardness number (VHN) were observed among the groups treated with the following diluted fruit nectars: diluted mandarin nectar ($75.9{\Delta}VHN$), diluted lemon nectar ($89.1{\Delta}VHN$), diluted grapefruit nectar ($91.7{\Delta}VHN$), and diluted orange nectar ($92.5{\Delta}VHN$). No statistically significant differences were found in the enamel surface hardness after erosion (p>0.05). Citric and malic acids were the major organic acids in the test fruits. The lemon and orange groups had the highest malic acid concentrations, and the mandarin group had the lowest malic acid concentration. Conclusion: The titratable acidity and the citric and malic acid contents of the fruits could be crucial factors responsible for enamel erosion. Therefore, fruit-based drinks should be regarded as potentially erosive.

• 유기물자원화
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• 제26권1호
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• pp.47-53
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• 2018

유기성 폐기물 소화공정의 발효액에서 젖산(lactic acid)을 회수하기 위해 화학침전법을 평가하였다. 젖산(lactic acid)의 회수율을 높이기 위하여 화학침전제 종류와 교반속도 및 침전시간 등 반응조건이 회수율 향상에 미치는 영향을 살펴보았다. 화학침전제의 종류에 관계없이 주입양이 증가할수록 젖산(lactic acid) 회수율이 증가하는 경향을 보였으며, CaO가 $Ca(OH)_2$와 $CaCO_3$에 비하여 높은 회수율을 나타냈다. CaO를 사용한 반응조건 최적화 실험결과, 교반속도 180 rpm, 침전시간 24 h, ethanol 주입량 25%(v/v)에서 회수율이 48%로 가장 높게 나타났다. 본 연구에서는 발효액 내 젖산(lactic acid)의 농도만 고려하여 주입할 침전제의 양을 계산하였기 때문에 실제 적용을 위해서는 발효액의 유기산 종류 및 농도를 고려하여 침전제의 투입량을 결정해야할 것이다. 유기물의 정성적 분석(FEEM, SEC) 결과로 볼 때 침전공정은 유기산의 특성에 큰 영향을 미치지 않았다.

• Mass Spectrometry Letters
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• 제11권4호
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• pp.82-89
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• 2020

A systematic isolation and characterization study for Cassia auriculata (CA) seeds resulted in identifying antidiabetic compounds 1,3,8-trihydroxyanthraquinone and quercetin, quercetin-3-O-rutinoside, gallic acid, caffeic acid, ferulic acid, and ellagic acid. The ultra-high-performance liquid chromatography based triple quadrupole mass spectrometry methodology was developed and validated for simultaneous identification and confirmation of these compounds from CA seeds. Multiple reaction monitoring (MRM) based quantification method was developed with MRM optimizer software for MS1 and MS2 mass analysis. The method was optimized on precursor ions and product ions with the ion ratio of each compound. The calibration curves of seven bioactive analytes showed excellent linearity (r2 ≥ 0.99). The quantitation results found precise (RSD, < 10 %) with good recoveries (84.58 to 101.42%). The matrix effect and extraction recoveries were found within the range (91.66 to 102.11%) for the CA seeds. This is the first MS/MS-based methodology applied to quantifying seven antidiabetic compounds in CA seeds and its extract for quality control purposes.

• 환경영향평가
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• 제9권1호
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• pp.75-86
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• 2000

The purpose of this work was to document the conditions regarding organic solvent exposure to the workers in paint industry. Air concentrations of organic solvents were measured by passive personal samplers and analyzed by a gas chromatography. Urine samples for hippuric test were also taken from 330 workers who have worked at seven domestic factories for more than two years. Amongst 25 organic elements detected in the indoor environment of working places, toluene was the most common element, and methanol showed the highest mean concentration(18.2ppm). A few elements including methylethyl ketone and toluene partially exceeded the Korean Permissible Exposure Limit. A lack of environmental facilities such as exhaust ventilation, automatic cleaning system, and personal safety devices at present work plaus brings about various occupational diseases.

• 농업과학연구
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• 제43권5호
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• pp.705-714
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• 2016

Organic acid and sugar contents in ten kinds of juices (two orange juices, two grape juices, two aloe juices, two citron juices, one bokbunja, and one grapefruit juice) were analyzed by high-performance liquid chromatography. Citric acid was detected in all the fruit juices analyzed. Grape juices contained the highest tartaric acid content (67.85 - 99.37 mg/100 mL) while orange and grape juices contained a high content of malic acid (151.67 - 211.18 mg/100 mL). Lactic acid was detected in all the aloe juices (35.12 - 65.27 mg/100 mL) as well as in one orange (203.8 mg/100 mL) and one grape juice (112.28 mg/100 mL). Citrus fruit juices (A, A', F) showed the highest content of total organic acids as 902.81 - 1,103.7 mg/100 mL. With regard to sugar contained in the juices, lactose and maltose were not detected in any of the fruit juices. Even when comparing the same kind of fruit juice, sugar (fructose, glucose, and sucrose) content showed a significant difference (p < 0.05) depending on the manufacturer. In the grape juices, contents of fructose (6.86 - 7.51) and glucose (6.23 - 7.3 g/100 mL) were higher than in other juices. One serving size of the juices (180 mL) analyzed in this study can provide approximately 3.3 - 4.9% of total daily energy requirements when consumed as part of the 2,200 kcal/day diet required for an adult.