• Korean Journal of Food Science and Technology
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• v.15 no.3
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• pp.209-214
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• 1983

Analytical methods on Stevia sweeteners are compared for their reproducibilities and recoveries. It is possible to separate stevioside, rebaudioside A, rebaudioside C, and dulcoside A through HPLC analysis. Steviolbioside, in addition to above 4 Stevia sweeteners, is detected through TLC scanner and TLC-FID assays. C.V.s on stevioside and rebaudioside A in HPLC analysis are 1.39 and 4.89%, which shows outstanding reproducibilities of this method. The recoveries of stevioside in HPLC, TLC scanner, and TLC-FID analyses are 97.7 89.4, and 97.3%. The recoveries of rebaudioside A in HPLC, TLC scanner, and TLC-FID assays are 90.8, 90.1, and 75.8%. Total content of Stevia sweeteners in 8 strains tested, ranges from 5 to 17% as dry weight basis.

• Journal of Naturopathy
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• v.10 no.2
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• pp.108-113
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• 2021

Background: Results on the action of antioxidants in extracts of Equisetum hyemale stems and roots have already been reported, but the antioxidant properties have not been analyzed. Purpose: This study was to determine the molecular structure of antioxidants in substances extracted from E. hyemale stems and roots. Methods: Component analysis was analyzed by HPLC and LC-MS after extraction with hot water and ethyl alcohol. Results: The HPLC chromatogram of stem and root extracts showed four significant peaks at a wavelength of 205 nm. Peak 1 at 280 nm is a typical simple phenolic type, and both peaks 2-4 near 280 nm and 370 nm are typical flavonoid glycosides. As for the antioxidant level of the extract by HPLC analysis, the sum of the peaks at 740 nm was the highest at 3,669 mAU in the 100% ethanol extract, 3,096 mAU in the 70% ethanol extract, and 2,868 mAU in the hot water extract. As a result of LC-MS analysis of the antioxidant extract, kaempferol-3-sophoroside-7-glucoside with a molecular weight of 772 da at peak 3, and kaempferol-3-sophoroside-8-glucoside with a molecular weight of 788 and 772 at peak 4 was identified. Conclusions: The above results show that two types of antioxidants were identified in the antioxidant extract of E. hyemale exrtracts. Therefore, the potential as a raw material for functional cosmetics has increased.

• Journal of Microbiology and Biotechnology
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• v.5 no.5
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• pp.302-304
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• 1995

As the previous HPLC method (Ogasawara et al., 1983) was described for the analysis of aclacinomycin A and some of its analogue compounds but not for aclacinomycin Y, we developed novel HPLC condition by optimizing solvent system. The newly developed solvent system allowed a complete separation of aclacinomycins Y and A, as opposed to the incomplete resolution of these two compounds in conventional method. The amounts of aclacinomycins Y and A could be accurately determined when the fermentation broth of Streptomyces lavendofoliae DKRS was analyzed by the newly developed method.

• YAKHAK HOEJI
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• v.38 no.4
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• pp.379-388
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• 1994

A new method for the analysis of metocurine iodide in biological fluids was developed. Metocurine iodide was quantitatively extracted with rose bengal from aqueous layer into dichloromethane layer and the amount of metocurine iodide was calculated from the amount of rose bengal which was determined by HPLC with fluorescence detector. It was possible to analyze metocurine iodide without the effect of co-prescribed drugs in the concentration range of $0.09{\sim}9.10\;{\mu}g/ml$. The detection limits of metocurine iodide in urine and blood were 0.8 and 1.2 ng at S/N=3, each respectively.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.71-77
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• 1997

Sulfonamides, a therapeutically important group of antimicrobial drugs, are widely used to treat and prevent the acute systemic and skin infections in dairy cattle. They also pose an economic hazard through inhibition of growth of dairy starter cultures. This study was carried out to compare four screening methods for detection of sulfamethazine in milk and determine the positive milk sample by HPLC method. Sulfamethazine was used to spike at five levels of sulfamethazine. The Lac-Tek test and CharmII test were also consistent better than TTCII test and Delvo SP test in sulfamethazine detection. Analysis probabilities of obtaining a positive response with TTCII test and Delvo SP test assay at 50 ppb sulfamethazine level in milk samples were only 14%, 42% each. Whereas using the Lac-Tek test and CharmII test would have resulted in 100% identification of the five levels. Determination of sufamethazine using the HPLC method in the spiked milk were 10.64, 19.30, 30.76,38.83 and 50.23 ppb, respectively.

• Analytical Science and Technology
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• v.10 no.6
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• pp.445-452
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• 1997

A simple and sensitive high performance liquid chromatography for analysis of Putrescine, Spermidine and Spermine in urine is described. The benzoyl chloride derivatives of Putrescine, Spermidine and Spermine are separated on a ${\mu}$ Bondapak $C_{18}$ reverse-phase column with methanol/$H_2O$(50/50v/v) as the mobile phase. The results show that the mean level of polyamines in uterine cancer patients urine is much higher than in normal human urine.

• Preventive Nutrition and Food Science
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• v.5 no.1
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• pp.7-9
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• 2000

Variouss concentrationss of free malonaldehyde were prepared from 1,1,3,3-tetraethoxy propane (TEP). Spectrophoto-metric determination and HPLC analysis of free malonaldehyde instead of malonaldehyde-thiobaribituric acid (MA-TBA) complex were conducted. Malonaldehyde was well separated on a $\mu$Bondapak C18 column. The absorbances at 254 nm and the HPLC peak areas of free malonaldehyde increased with the increase in its concentration. The correlation coefficient between absorbances and peak areas was 0.998. The total time elapsed to conduct the whole procedure was less than 15 minutes. This method directly measured the amount of free malonaldehyde in a short period of time successfully. This procedure is expected to be used as a rapid, accurate and specific means to de-termine the development of lipid oxidation in food.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.5
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• pp.581-585
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• 1993

Five flavonoids isolated from the ethyl acetate fraction of Cedrela sinensis A. Juss. were identified by high performance liquid chromatography. Separation was achieved by reversed phase chromatography on ${\mu}-bondapak$ C18 column with isocratic elution method. The content of the major flavonoid, quercitrin was about 9.48%(w/w) and 37.06%(w/w) for the methanol extract and ethyl acetate fraction, respectively.

• Analytical Science and Technology
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• v.16 no.1
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• pp.78-81
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• 2003

Peptides separation in high performance liquid chromatography (HPLC) is very important for the analysis of total proteins using mass spectrometry rather than two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In this study, we investigated the optimal HPLC condition of peptides for the use of mass fingerprinting. As a result of pursuing a combination of solvent additives for HPLC, water and acetonitile containing both 0.1% trifluoroacetic acid and 0.1% acetic acid respectively showed the most efficient resolution and sensitivity.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.1 no.1
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• pp.20-28
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• 1995

The conditions of Soxhlet extraction and HPLC analysis were examined for the determination of antioxidants used for polyolefins manufacturing. The extraction with methylene chloride in a Soxhlet apparatus for 10 hours and above provides almost complete recovery of the additives from polyolefins. The determination of the antioxidants including BHT, Irganox 1076, Irganox 1010 and Irgafos 168 could be successfully performed by using reversed-phase HPLC under gradient elution where the baseline separation of all four antioxidants in a single run was possible. In addition, the antioxidants inherently contained in commercial LLDPE and OPP films were identified and quantitatively determined.