• 한국환경과학회지
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• 제14권6호
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• pp.525-532
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• 2005

Polyelectrolyte titration, which was called colloid titration is based on the stoichiometric reaction between oppositely charged polyelectrolytes, This can be used, for instance, to determine the charge density of a cationic polyelectrolyte, using an anionic polyelectrolyte of known charge density, such as potassium polyvinyl sulfate (PPVS). The technique requires a suitable method of end-point detection and there are several possibilities. In this work, two methods have been investigated: visual titrimetry based on the color change of a cationic dye (o-toluidine blue, o-Tb) and spectrophotometry based on the absorbance change corresponding to the color change of the same dye. These have been applied to several cationic polyelectrolytes with different charge density and molecular weight. In all cases, the cationic charge was due to quaternary nitrogen groups. In the case of cationic dye, it was shown that the sharpness depends on the charge density of cationic polyelectrolyte. With the polyelectrolytes of lower charge density, the binding to PPVS is weaker and binding of the dye to PPVS can occur before all of the polyelectrolyte charge has been neutralized. However, by carrying out titrations at several polyelectrolyte concentrations, good linear relationships were found, from which reliable charge density values could be derived. Effects of pH and ionic strength were also briefly investigated. For cationic polyelectrolytes (copolymers of acrylamide and dimethylaminoethy] acrylate), there was some loss of charge at higher pH values, probably as a result of hydrolysis. Increasing ionic strength causes a less distinct color change of o-Tb, as a result of weaker electrostatic interactions.

• 한국식생활문화학회지
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• 제34권6호
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• pp.761-770
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• 2019

Two experiments were conducted to determine how much sodium in food could be detected using a salinity meter. First, the salinity of mixed solutions of 0 to 6% sugar, 0 to 5% oil, and 0 to 6.4% MSG in a 1% NaCl solution was measured using a salinity meter and a Mohr titration method, and the results were compared with the calculated sodium expectations. As a result, the sodium contents of the sugar solutions and MSG solutions measured using a salinity meter were lower than the expected concentrations at 2% or more and 0.8% or more, respectively (p<0.05). The salinity of the 18 HMR products was measured in the same way, and the results were then compared with the sodium contents of the nutrition facts. The average sodium content of all products measured using the salinity meter and Mohr method was 1.12 times and 1.06 times the sodium content of the nutrition facts, respectively. On the other hand, the differences between the products were significant. The correlation coefficients between the nutrition facts and salinity meter, the nutrition facts and the Mohr method, and the salinity meter and Mohr method were 0.885, 0.920, and 0.950, respectively (p<0.01).

• 분석과학
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• 제33권6호
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• pp.252-261
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• 2020

Currently, the potentiometric titration and the high pressure liquid chromatography (HPLC) method were utilized in Korean Pharmacopoeia XII (KP XII) as well as other pharmacopoeias (USP, EP, BP) for determination of loperamide hydrochloride in raw materials and capsules, respectively. The research objective is to overcome the remaining drawbacks from current methods such as solubility of mobile phase (KP XII), less scientific approach (USP 43) or using paired-ion chromatography reagent which shows some limitations (BP2017 and other formulation monographs). The proposed method was optimized by Design of Experiment (DoE) tool to obtain the satisfied method for determination of loperamide hydrochloride. The optimal condition was performed on the common C18 column (150 mm × 4.6 mm; 5 ㎛) using isocratic elution with the mobile phase containing 40 mM of potassium phosphate monobasic (pH 3.0) and acetonitrile (56:44), at a flow rate of 0.7 mL/min. The optimized method was validated and met the requirements of the International Conference on Harmonization. The developed method was applied to determine loperamide hydrochloride in capsules and can be used to update the current monograph in KP XII.

• 분석과학
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• 제30권3호
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• pp.154-158
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• 2017

The Korean Pharmacopoeia (KP XI), British Pharmacopoeia (BP 2013) and Japanese Pharmacopoeia contain monographs for the quality control of raw fusidate sodium and its formulations using high performance liquid chromatography (HPLC). However, the assay method for the determination of fusidate sodium in commercial tablets is titration which is less specific than HPLC. In this study, we present an alternative HPLC method for quantitation of fusidate sodium in tablets. Method validation was performed to determine linearity, precision, accuracy, system suitability, and robustness. The linearity of calibration curves in the desired concentration range was high ($r^2=0.9999$), while the RSDs for intra- and inter-day precision were 0.25-0.37 % and 0.11-0.60 %, respectively. Accuracies ranged from 99.46-100.85 %. Since the system suitability, intermediate-precision and robustness of the assay were satisfactory, this method will be a valuable addition to the Korean Pharmacopoeia (KP XI).

• 생명과학회지
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• 제22권6호
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• pp.703-712
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• 2012

AAV는 매우 안전하고 효율적인 유전자전달방법으로 인정되어 왔다. 그러나, AAV가 가진 생물의약품으로서 단점은 효율적이고 재현성 높은 생산법이 취약하고, 또한 다양한 혈청형을 간단한 한 가지 공통적 방법으로 신뢰성 있게 정량하는 방법이 개발되어야 하는 것이다. 따라서, 본 연구에서는 AAV2와 아데노바이러스를 동시에 감염하는 종래의 생산법에 의한 효율성과 새로운 생산법, 즉 AAV2 감염 후 pHelper 플라스미드를 transfection 하는 방법을 통한 생산효율성을 비교하였고, HEK293과 293T를 생산세포주로 하여 시간에 따른 생산효율성도 분석하였다. 그 결과 AAV2와 pHelper DNA를 포함한 새로운 생산법은 기존의 방법에 비해 10배 이상 높은 생산효율성을 보였고, 293T에서 AAV2를 10 MOI로 감염한 후 5일째에 가장 높은 생산효율성을 보였는데, 생산세포 한 개 당 $1.61{\times}10^5$ virus genomes (v.g.)을 생산하는 결과였다. 따라서 이 생산조건을 다른 혈청형 생산에 적용한 결과, 모든 혈청형에서 생산세포주 한 개 당 $10^5$ v.g. 이상을 생산하는 효율성을 보였다. 한편, 다양한 AAV 혈청형을 한 가지 공통적인 방법으로 정량하기 위해 the universal PCR 프라이머를 제작하였고, 그것을 이용하여 신뢰성 높고 10개 분자까지도 증폭이 가능한 결과를 모든 혈청형에서 얻었다. 그러므로 이 한 쌍의 정량용 the universal 프라이머는 임상시험용 아데노바이러스벡터에 존재하는 AAV오염을 검출하는 것에도 사용 가능하다.

• 대한수의학회지
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• 제35권1호
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• pp.131-135
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• 1995

This study was performed to develop immnoassay method of detecting the residual tylosin and to investigate the residues using HPLC(high performance liquid chromatography) in animal products. Obtained results are the followings: 1. To develop immunoassay method, the conjugation of activated tylosin tartarate ester derivatives and BSA (bovine serum albumin) was certified at the 290nm of maximal absorbance which tylosin tartrate have. 2. The titration of anti-serum produced from rabbit immunized with the conjugator as an immunogen was too low to analyze the tylosin. 3. The residual tylosin can be detected by 0.2 ppm using HPLC. 4. Recovery of tylosin from spiked pork samples measured using HPLC was $87.4{\pm}4.0%$. 5. When the levels of tylosin residues in swine liver and kindney were measured on HPLC. The level was over the maximum tolerance level in one out of ten samples of each organ.

• 한국식품과학회지
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• 제34권3호
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• pp.361-364
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• 2002

식품첨가물중 제조용제로 사용되고 있는 산소에 대해 우리실정에 적용 가능한 시험방법을 확립하기 위해 국내에서 유통되고 있는 과즙음료 5종 25품목 및 시판 생수 1종 5품목 등 총 6종 30품목의 음료중의 용존산소량을 분석한 결과는 다음과 같다. 적정법은 실제 첨가된 산소량보다 낮게 검출되었으며 전처리를 포함하여 분석시간이 많이 소요되고 많은 양의 시료가 요구되며 hydroxylamine과 $N_2O_4$ 등 다른 방해물질의 영향과 DO고정에 사용되는 시약(황산망간, 염화망간)의 첨가량에 따라 용존산소량에 영향을 미치는 문제점이 있는 반면에, 폴라로그라피법은 실제 첨가된 산소량에 근접하게 검출되었으며 분석기간이 짧고 사용이 간편하며 측정 물질을 분리하기 않고 직접 측정할 수 있는 장점이 있어 다량의 시료를 분석하는데 적합하였다. 따라서, 국내유통되고 있는 산소가 첨가된 또는 산소가 첨가되지 않은 음료에 대하여 폴라로그래피법을 적용하여 산소량을 분석한 결과, 산소가 첨가된 과즙음료에서는 $23.10{\sim}72.60\;ppm$, 산소가 첨가되지 않은 혼합음료에서는 $0.70{\sim}2.84\;ppm$, 시판되고 있는 생수의 경우는 $7.63{\sim}8.28\;ppm$범위로 각각 검출되었다. 이상의 시험결과로서 우리 실정에 맞는 음료중 산소 분석방법으로는 간편하고 경제적이며 다량의 시료를 신속하게 분석할 수 있는 폴라로그라피법이 적합하였으며 동 시험법은 추후 산소를 함유한 제품의 효율적인 품질관리에 기초자료로 활용 가능할 것으로 기대된다.

• Laboratory Medicine Online
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• 제1권1호
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• pp.57-63
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• 2011

배경: ABO 혈액형의 동종응집소 역가는 ABO 부적합 골수이식 또는 장기 이식에서의 경과 관찰 및 치료평가 등에 도움을 주나, 미세원주응집법이나 시험관법 등 검사법에 따라 영향을 받을 수 있다. 저자들은 시험관응집법과 미세원주응집법을 이용한 동종응집소 역가의 분포를 비교 평가하였다. 방법: 2010년 4월부터 8월까지 4개월간 고려대 구로병원에서 검진을 받은 20세 이상의 건강한 성인 중 O형 환자 23명, A형 환자 20명, B형 환자 20명을 대상으로 실온식염수 시험관응집법, 미세원주응집법, 항글로불린 시험관응집법과 항글로불린 미세원주응집법의 네 가지 방법을 동시에 시행하였다. 결과: 시험관 응집법, 미세원주응집법, 항글로불린 시험관응집법, 항글로불린 미세원주응집법 네 가지 방법으로 측정한 O형 환자들의 동종응집소 역가의 중앙값은 각각 항-A는 64 (8-512), 64 (8-512), 128 (8-2,048)과 128 (16-2,048)이고, 항-B는 64 (16-128), 128 (16-256), 128 (16-512)과 256 (16-512)였다. 동일한 네 가지 방법으로 측정한 A형 환자들의 항-B 동종응집소 역가의 중앙값은 각각 64 (8-128), 64 (8-128), 32 (8-128), 64 (8-256), B형 환자들의 항-A 동종응집소 역가의 중앙값은 각각 64 (16-128), 128 (8-128), 128 (8-256), 256 (8-256)였다. 네 가지 동종응집소 측정 모두에서 항글로불린 미세원주응집법이 가장 높은 역가를 보였다. 미세원주응집법에 의한 역가는 실온식염수 시험관응집법에 의한 역가와 같거나 한 단위 역가만큼 더 높았다. 항글로불린 미세원주응집법으로 측정한 역가는 항글로불린 시험관응집법으로 측정한 역가와 같거나 한 단위 역가만큼 더 높았다. 네 가지 방법에 의한 동종응집소 역가의 기하평균은 O형 환자의 항-A, 항-B, A형 환자의 항-B 및 B형 환자의 항-A 모두 남자보다 여자가 더 높은 값을 보였다. 결론: 항글로불린 미세원주응집법이 네 가지 방법 중 가장 민감한 방법이었다. 항글로불린을 첨가한 동종응집소 역가 측정이 장기 이식 등의 임상 판단에 중요하며 시험관응집법에 비해 미세원주응집법에 수기 과정이 간편함을 고려할 때 항글로불린 미세원주 응집법을 사용하여 기관 간 변이를 측정한다면 동종응집소 역가 표준화에 기여하리라 사료된다.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2618-2626
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• 2010

In this paper poly (4-methyl vinylpyridinium hydroxide)/SBA-15 composite was prepared as a highly efficient heterogeneous basic catalyst by in situ polymerization method for the first time. It was characterized by XRD, FT-IR, BET, TGA, SEM and back titration using NaOH. This catalyst exhibited the excellent catalytic activities for the Knoevenagel condensation of various aldehydes with ethyl cyanoacetate. Over this catalyst, ${\alpha},{\beta}$-unsaturated carbonyl compounds were obtained in the reasonable yield at $95^{\circ}C$ in 10 - 30 min in $H_2O$ as a solvent with a 100% selectivity to the condensation products. Catalyst could be easily recycled after the reaction and it could be reused without the significant loss of activity/selectivity performance. No by-product formation, high yields, short reaction times, mild reaction conditions and operational simplicity with reusability of the catalyst were the salient features of the present synthetic protocol. Presence of $H_2O$ as a solvent was also recognized as a "green method".

• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2003년도 제23차 추계총회 및 국제학술심포지움
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• pp.26-32
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• 2003

Rice is one of the most important cereals in the world. Japanese people use about 9 million tons of rice per you. We use rice for cooked rice as staple foods and for processing, such as rice wine (sake), rice crackers and miso fermentation, etc. Palatability, eating quality, of rice is evaluated by the sensory test and various kinds of physicochemical measurements. Japanese National Food Agency started the storage of 1.5 million tones of rice in 1996. We carried out the storage test using high quality rices since 1995 until 1996. As indices for the quality deteriorations of rice grains during the storage, germination ratio, enzyme activities, fat acidity, physical properties of cooked rice were clarified to be useful. We applied colorimetric method for the measurements of fat acidities in the place of titration method. Processing suitabilities of rice differ depending on the products. Low amylose rice is more suitable for soft rice crackers and high amylose rice is preferred more for rice noodle. Pre-cooked rice products, such as frozen cooked rice, retort-pouched rice and aseptic rice, are increasing recently in Japan. In addition to above-mentioned physico-chemical tests, NIR spectroscopy,“Midometer”and“Taste sensor”are novel and useful to evaluate eating quality and processing suitabolities. Recently, rice wholesalers and retailers have been obligated to display the name of cultivar, location of cultivation and the year of production of rice grains which they sell by the Japanese Agricultural Standard Law (JAS). In order to detect the dishonest labeling of rice cultivars, we developed new cultivar identification method based on DNA polymorphism.