• Journal of Food Hygiene and Safety
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• v.5 no.4
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• pp.213-217
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• 1990

A simple and practical method for the determination of caffeine in coffee, black tea and green tea was studied. The analysis of caffeine was performed by reverse phase high perfomance liquid chromatography using a ${\mu}-Bondapak$ C18 column at isocratic condition with methanol-acetic acid-water (20: 1: 79) on UV detector at 280 nm. The extraction and clean-up of caffeine in sample is based on combing a simple pretreatment with the use of a Sep-Pak Alumina A cartridge. The average recoveries of caffeine from several samples were 95.2 -101.3%, the relative standard deviation for the whole procedure was 0.10 ~ 0.62%, and the detection limit of caffeine in sample solution was about $0.1\;\mu\textrm{g}\;per\;ml$.

• Analytical Science and Technology
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• v.36 no.1
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• pp.22-31
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• 2023

As the use of e-liquid cigarettes is rapidly increasing worldwide, it multiplies the potential risk undisclosed to the health of non- and smokers. To reduce the hazard, each country has its own set of regulations for controlling e-liquids. In Korea, the narrow definition of tobacco makes it difficult and have been steadily occurring tax evasion exploiting the difference in natural and artificial nicotine. Therefore, it is very important to distinguish source of nicotine for their regulation. To find biochemical discriminant markers, this study established analysis methods based on high-performance liquid chromatography coupled with diode array detector (HPLC-DAD) and high-performance liquid chromatography coupled with triple Quadrupole mass spectrometry (HPLC-MS/MS) for nicotine enantiomers and tobacco alkaloids targeted using the difference in pathways of nicotine biosynthesis and chemical synthesis. The method was validated by experimenting linearity (R² > 0.999), recovery (80.99-108.41 %), accuracy (94.11-109.73 %) and precision (0.04-8.27 %). Then, the results for discrimination of the nicotine obtained from analysis of 65 commercial e-liquid products available in Korean market was evaluated. The method successfully applied to the e-liquids and one sample labelled 'synthetic nicotine' for tax exemption was found to contain a natural nicotine product. This method can be used to determine whether an e-liquid product uses natural or artificial nicotine and monitor non-taxable e-liquid products. The method is more scientific than the existing one, which relies only on field evidence.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2011-2016
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• 2009

To resolve the differentiation problem of acetone and acrolein in the analysis of carbonyls by high-performance liquid chromatography (HPLC), we investigated the optimum analytical conditions for their separation. Carbonyl compounds were collected by 2,4-dinitrophenylhydrazine (DNPH)-coated cartridges. We examined the influence of three experimental variables: temperature (25, 30, 40, 50 and 60 ${^{\circ}C}$), flow rate (1.0 and 1.2 mL/min), and relative mobile phase composition (among acetonitrile, water and tetrahydrofuran). The experimental results revealed the optimum analytical condition of a flow rate of 1.2 mL/min, temperature of 32 ${^{\circ}C}$ and mobile phase composition of acetonitrile: water: tetrahydrofuran = 34 : 52.8 : 13.2. The analysis of indoor air composition indicated that acrolein and acetone comprised 11% and 42% of all aldehydes, respectively.

• Journal of Applied Biological Chemistry
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• v.58 no.4
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• pp.377-381
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• 2015

The content analysis of 6-gingerol, which is an active compound, in Zingiber spp. (Z. officinale and Z. mioga) and their commercial foods (ginger teas and powders) was conducted using high-performance liquid chromatography. A reverse phase system was used, with a gradient solvent system of water and acetonitrile. The 6-gingerol content was highest in the methanol extract of Z. officinale root (17.09 mg/g extract) and ginger powder B (15.92 mg/g extract). The results demonstrated that this method was simple and reliable for the quality control of Zingiber commercial foods.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.509-512
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• 1994

High performance liquid chromatography (HPLC) analysis was applied for determination of guanine plus cytosine (G + C) contents of DNA of Butyrivibrio fibrisolvens. By values of G + C contents, a reference strain and 20 wild strains of B. fibrisolvens were classified into at least two distinct subgroups, i.e. G + C contents of 18 strains were 38-40 mol% and those of 3 strains including the reference strain were 43-45 mol%. Clear relationships were not observed between G + C contents and biological properties of 21 strains of B. Fibrisolvens.

• Korean Journal of Pharmacognosy
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• v.11 no.2
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• pp.75-80
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• 1980

The decoctions and extracts were prepared on the traditionally prescribed four kinds (Kejigamcho-tang, Kejibanha-tang, Keji-tang, Kejiinsam-tang) of preparations containing Cinnamoni Raulus. The contents of cinnamic acid and cinnamic aldehyde in these preparations were determined by high performance liquid chromatography using reverse phase partition column, and 12% MeOH as eluting solvent. The sample was determined using the two wave length, 254nm and 280nm. This method was sucessfully applied to the analysis of cinnamic acid and cinnamic aldehyde of various preparations containing Cinnamons.

• Analytical Science and Technology
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• v.5 no.3
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• pp.339-343
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• 1992

The content of lysophosphatidyl choline (LPC) in wheat starch lipids from six cultivar representing three classes of wheat was determined by a high performance liquid chromatography using UV-detection (HPLC-UV). The HPLC-UV assay had a sensitivity of LPC concentrations above $5{\mu}g/50{\mu}l$ and required 80 minutes per chromatogram.

• Korean Journal of Plant Resources
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• v.20 no.3
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• pp.263-266
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• 2007

High performance liquid chromatography (HPLC) was used for the analysis of chiisanoside in each stem and root of Acanthopanax senticosus collected from South Korea, North Korea, China and Russia. A reverse-phase system using a gradient of H$_{2}$O and acetonitrile as the mobile phase was developed and detection was at 210nm. The analysis was successfully carried out within 30 min. Chiisanoside was measured in the stem and root of A. senticosus collected from various countries.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.35-39
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• 2004

The method for the chiral analysis of (-)-yatein was developed and the distribution of this component in the plants of three genera like Juniperus, Thuja and Chamaecyparis belonging to Cupressaceae family was examined. The chiral analysis of (-)-yatein from the plants was carried out by high performance liquid chromatography on (R,R)-Whelk-O1 column using 81 v/v% methanol as mobile phase. The yatein content in the leaves of Juniperus was the highest in compare with that of the other two genera, providing the possibility of the chemical discrimination of the plants in Juniperus from the other plants in the Cupressaceae family. In general, the yatein content in the leaves was much higher than that in the twigs. This method could be applied for the quality control of (-)-yatein in the plants belonging to Cupressaceae family.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.353-358
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• 2023

Barley (Hordeum vulgare) belongs to the Poaceae family. This study compared the polyphenol and flavonoid levels of unfermented and fermented barley sprouts using spectrophotometric assays. The findings indicated that fermentation greatly boosted the flavonoid content but caused only a slight increase in the polyphenol content. However, this does not imply that fermentation has no effects whatsoever on the polyphenol content of barley sprouts. This was due to the fact that some flavonoids cannot be detected by the wavelength used to calculate the overall polyphenol concentration. Both samples were subjected to high-performance liquid chromatography analysis and detected the flavonoids lutonarin, saponarin, isoorientin, isovitexin, and tricin-all of which have bioactive properties-most notably known for their antioxidant activity. These results augment the ongoing phytochemical profiling research and can possibly valorize the already thriving barley industry.