• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.537-544
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• 2013

This study was performed to establish method of simultaneous determination of fructose, glucose, and sucrose in honey and commercial vitamin drinks by GC and GC/MS. Optimum chromatographic separation of trimethylsilyl-oxime (TMSO) derivatives by GC was achieved on a DB-5 column. Calibration curves for fructose, glucose and sucrose TMSO derivatives by GC were linear in the range of 50-5000 ${\mu}g/mL$, and their $r^2$ values were 0.9999, The limit of detection and limit of quantification of fructose, glucose, and sucrose were 0.68, 0.47, and 0.53 ${\mu}g/mL$, respectively, and 2.27, 1.58, and 1.77 ${\mu}g/mL$, respectively. Average recoveries of fructose, glucose, and sucrose were 100.5, 101.0, and 99.7%, respectively. When the method was applied to 12 honey samples, the average concentrations of fructose, glucose and sucrose were $42.58{\pm}1.97%$, $27.74{\pm}1.16%$, and $0.79{\pm}0.52%$, respectively. The F/G ratio was $1.53{\pm}0.07$. For fructose and glucose contents, results from the GC analysis were similar to those from the HPLC analysis, but the sucrose content was different for each analysis method. We suggest that the GC method is more suitable than other official analytical methods for simultaneous determination of fructose, glucose, and sucrose in honey.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.3
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• pp.275-282
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• 2011

Novel whitening agents were prepared using peptide-Natural origin compound derivatives. The peptide could be an antagonist of MC1R and Natural origin compound were well-known material as a Tyrosinase inhibitor. We also suggest the new assay method which could evaluate the Antagonistic effectiveness to MC1R using cAMP signaling pathway. 24 candidates were synthesized and 11 peptide derivatives were selected by cAMP assay method. To evaluate cAMP assay, the selected peptide derivatives were assayed to evaluate their melanogensis inhibitory activity. At this work, we could know that the sequences which include -RW- have a melanogensis inhibitory activity, and cAMP assy could use as a evaluating method of MC1R antagonist. But, to evaluate the whitening activity of some material, cross-checking with melanin inhibitory assay method was recommended.

• Analytical Science and Technology
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• v.15 no.5
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• pp.445-450
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• 2002

A sensitive gas chromatographic method has been established for the determination of total iodide in seawater as their volatile organic derivative. The method is based on the formation of 4-iodo-2,6-dimethylphenol with 2,6-dimethylphenol in matrix and a single-step extraction of the derivative with ethyl ether, which are then measured by gas chromatography-mass spectrometry (selected ion monitoring). Iodate in sea water was completely reduced to iodide with ascorbic acid and acetic acid. The detection limit was 0.1 ng/mL in seawater and the calibration curve showed good linearity with r=0.9997. The method was sensitive, reproducible and simple enough to permit the reliable routine analysis of total iodide in seawater. Total iodide in sea water was found about 30 ng/ml.

• Analytical Science and Technology
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• v.28 no.2
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• pp.112-116
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• 2015

Extraction of quaternary ammonium compounds (choline and betaine) from plant samples (spinach) using ion exchange resin (AG1, OH⁻ form) is a very simple and inexpensive approach. However, it is very hard to determine amounts of choline and betaine simultaneously using high-performance liquid chromatography-ultraviolet (HPLC-UV) detection. Unlike choline, betaine has low molar absorptivity in UV-visible (UV-Vis) region, which makes it difficult to carry out UV-Vis detection of betaine. The mixture of quaternary ammonium compounds (choline and betaine) was derivatized using 2-bromo acetophenone as a derivatizing agent. As a result, choline did not react with the derivatizing agent, whereas betaine formed a betaine derivative. This betaine derivative exhibited detectable UV absorption with baseline separation between choline and the betaine derivative. Thus, with this method, choline and betaine can be determined simultaneously by using the HPLCUV method through one-step derivatization, which is an easy, sensitive, and reliable method.

• Bulletin of Food Technology
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• v.15 no.2
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• pp.76-84
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• 2002

일부 야생 및 배양 버섯중의 sterol 및 vitamin $D_2함량을 측정하였다. 야생버섯의 부위별 이들 성분의 분포 또한 평가되었다. 또 야생버섯의 자실체의 vitamin $D_2함량의 변화도 연구되었다. vitamin $D_2는 비누화 및 반예비 순상 HPLC 정제를 포함하는 방법을 사용한 후 HPLC법을 사용하여 측정하였는데, 내부 표준품을 이용한 분석용 역상컬럼을 이용한 정량을 하였다. Sterol 함량은 GC로 분석되었으며, 내부표준품을 사용하였다. 비누화 후에 sterol을 trimethylsily1 ester로 유도체화하여 분석의 시료로 하였다. 질량분석이 sterol류의 동정을 확인하기 위하여 사용되었다. 배양 버섯에서는 vitamin $D_2는 거의 존재하지 않았으나, 일부 야생 버섯은 이들 vitamin을 다량(4.7- 194$\mug$/ 100g 건물중) 함유하고 있었다. Ergosterol은 버섯류 중에 가장 많이 존재하는 sterol이었으며, 야생버섯류(296-489 mg/ 100g 건물중)보다 배양버섯류(602.1-678.6 mg/ 100g 건물중)에서 높은 함량을 보였다. Vitamin D2와 ergosterol의 함량은 버섯류의 부위에 따라 아주 다양하거나 적당한 변화를 보였으며, 자루부위에서 가장 낮은 함량을 보였다. 더욱이 개체별 자실체간의 vitamin $D_2함량간에도 많은 차이를 보였다.

• Analytical Science and Technology
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• v.13 no.3
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• pp.385-393
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• 2000

A gas chromatography-mass spectrometric (GC/MS) procedure for the determination of amineptine (dihydro-10, 11-dibenzo[a, d] cycloheptenyl-5-amino-7-heptanoic acid) and its main metabolites in human urine was described. Amineptine has been known to be extensively metabolized by the ${\beta}$-oxidation of the heptanoic side chain with formation of pentanoic side chain metabolite ($C_5$-metabolite), and lactamizarion by internal dehydration of (${\beta}$-oxidized metabolite (${\delta}$-lactam). The detection of these compounds was based on acid hydrolysis, liquid-liquid extraction and trimethylsilylated derivatization of the carboxylic acid group. For the determination of amineptine and its metabolites in biological fluids, selected ions at the m/ 192, molecular ion and one of the characteristic ions were monitored by GC/MS. On the excretion study of amineptine in human urine, 70-90% of amineptine, ${\delta}$-lactam, and $C_5$-metabolite were found to be excreted within 4 hours and their excretion completed within 20 hours.

• Journal of Food Hygiene and Safety
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• v.8 no.1
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• pp.9-15
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• 1993

In an attempt to quantitate and qualitate residual antibiotics and antibacterial agents in meat simultaneously, we studied a gas chromatography-mass spectrometry(GC/M8) analysis. For a simultaneous analysis of penicillin G, chloramphenicol and thiamphenicol in meat, a simple and rapid clean-up procedure including extraction with 0.01 M EDTA-2Na Mcilvaine buffer (pH 4.0), defatting with n-hexane, and elution with 0.01M-methanolic oxalic acid from Bond Elute $C_{18}$ cartridge, and quantitation by selected ion monitoring (SIM) mode after derivatization was performed. The recoveries (%) of penicillin G, chloramphenicol and thiamphenicol (CV, %) at 1 ppm fortification level were 63.5 (7.6), 76.3 (8.1) and 84.7 (2.0), and the detection limits of those were 0.6, 0.085 and $0.084\;\mu\textrm{g}$ beef, respectively. This method using 81M mode allows excellent detection and quantitation of residual antibiotics and antibacterial agents in meat. Moreover, confirmation by a full scan electron impact mass spectrum is possible if residual level in the sample in above 1 ppm.

• Analytical Science and Technology
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• v.18 no.5
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• pp.444-451
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• 2005

The accurate and simple extraction method for sterols and fatty acids in sesame oil was developed. The new method improved the extraction efficiency of sesamin in sesame oil and the ratio of sesamin over campesterol. It will be applied to judgement of adulteration of plant edible oils. The minor components of sterols were also confirmed. The simultaneous determination of sterols and fatty acids with derivatization were processed, but it was not enough to confirm adulteration, thus need more experiments.

• Analytical Science and Technology
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• v.11 no.6
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• pp.429-435
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• 1998

Free and glycine conjugated bile acids were detected fluoromatrically in high-performance liquid chromatography after derivatization with dansyl cadaverine. The coupling agent, diethyl phosphorocyanidate was used to form the amide bond between dansyl cadaverine and analytes. The dansyl derivatives of 8 bile acids were separated successfully on Cosmosil ODS column by using linear gradient elution of 20% MeOH-water/$CH_3CN$. The detection limits of cholic acid was reached 10 pg(S/N=5) per $1{\mu}l$ of injected volume. This new derivatization method would be applicable to detect the changes of bile acids in biological samples.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.442-446
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• 1997

A new analytical method was developed by HPLC after supercritical fluid extraction and fluorogenic derivatization for the determination of quinclorac (3,7-dichloro-8-quinoline carboxylic acid) in soil. The graminicide quinclorac was extracted from soil by supercritical fluid extraction. Supercritical carbon dioxide at 7000 psi $(80^{\circ}C)$ modified with 30% of methanol extracted quinclorac from soil samples at the level of $0.1ng\;g^{-1}$ with 96% recovery. Extracted quinclorac was determined by HPLC as a fluorescent derivative. Derivatization was made with 4-bromomethyl-7-methoxycoumarin (4-Br-Mmc) using 18-crown-6-ether as a catalyst. The conversion was completed within 30 min and the limit of detection was 0.5 ppb to prove that the procedure could be used in the residue analysis of the pesticides containing carboxylic acid group.