• Bulletin of the Korean Chemical Society
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• v.21 no.6
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• pp.623-627
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• 2000

Aggregation of hydrophobically end-capped poly(ethylene oxide)s: HEURs, denoted as $C_8$$EO_{380}$$C_8$, $C_12$$CO_{600}$$C_{12}$, and $C_{18}$$EO_{860}$$C_{18}$,are described using static fluorescence, dynamic light scattering, and atomic force microscope (AFM) techniques. The CAC (critical aggregation concentration) was determined by com-paring two fluorescent peaks which were influenced by the polarity of the probe dye molecules, pyrene. The aggregation occurs in concentrations higher than 10 g/L of $C_8$$EO_{380}$$C_8$ and the CAC decreases by increasing the side chain length. The dynamic light scattering experiment shows fast mode and slow mode decays, and both are diffusive. The fast mode does not depend on the concentration, but the slow mode shows concentration dependence influenced by the formation of an aggregated structure. The hydrophobic end groups effect more dominantly than the main chains for the formation of HEUR micelles. By increasing the concentration, the HEUR micelles change their structure from spheres to rodlike micelles, and finally make fused structures, which were visualized with atomic force microscopy.

• Analytical Science and Technology
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• v.16 no.5
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• pp.339-348
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• 2003

Determination of some PAHs in used engine oils have been carried out by extraction of the components into acetonitrile followed by GC/FID and synchronous spectrofluorimetric technique. 7 PAHs, such as acenaphthene (Ace), anthracene (Anth), benzo(a)pyrene (BaP), chrysene (Chry), phenanthrene (Phen), fluoranthene (Ft), and perlyrene (Per) in used engine oil sample were able to determine separately by synchronous spectrofluorimetry. Calibration curves for those components were linear for the concentration range of 0.4~166 ppb PAHs with the corelation factor of 0.9985~0.9999. The peak areas produced by GC/FID split ratio program were used for the calibration curves of the other 8 PAHs. Detection sensitivity of the synchronous spectrofluorimetry seems to be 100 times more sensitive than GC/FID method. The total amount of PAHs in the used engine oil were 5.5 ng/g for LNG (bus), 10.5 ng/g for LPG(taxi), 92.2 ng/g for gasoline-passenger car, and 130 ng/g for diesel trailer, respectively.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.157-161
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• 2009

This paper proposes an analytical method for determining amounts of polycyclic aromatic hydrocarbons (PAHs; benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i] perylene) in coffees beans. Soxhlet extraction and liquid/liquid extraction were tested for the quantification of seven PAHs. Soxhlet extraction was followed by cyclohexane extraction and used a silica cartridge. Liquid/liquid extraction was followed by n-hexane extraction and utilized a florisil cartridge. The extracts were analyzed by HPLC-fluorescence detection (FLD) with a Supelcosil LC-PAH column. The PAH recoveries ranged from 78.68 to 96.28% for the liquid/liquid extraction, and from 67.47 to 84.60% for the Soxhlet extraction.

• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.21-26
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• 2009

Polycyclic aromatic hydrocarbon(PAH) contents were evaluated in sesame oils from sesame seeds of different origins and in commercial samples using HPLC with fluorescence detection. The sesame seeds, which had been harvested from India, China, and Korea, were roasted at $250^{\circ}C$ for 25 min, and the commercial sesame oils were purchased from a local market. The recoveries for eight PAHs spiked into the sesame oils ranged from 80.2 to 99.2%. The mean levels of total PAHs in the sesame oils harvested from China, Korea, and India were 3.97, 1.57, and 1.20 ${\mu}g$/kg, respectively. The PAH contents in the commercial sesame oils ranged from 0.79 to 2.15 ${\mu}g$/kg.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.122-127
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• 2024

Cosmetic preservatives are an important class of ingredients in terms of ensuring sustainable use and providing customer satisfaction. Recently, a great deal of interest has been drawn to the production and use of toxic-free, naturally derived preservatives. In this work, a new naturally derived preservative (laurimino bispropanediol, LB) was developed to replace the most widely used diol preservatives, such as 1,2-hexanediol or 1,2-octanediol. The basic properties of the obtained preservative were measured, and the solution behavior of the preservative in an aqueous medium was examined. The feasibility of micelle formation in the preservative solution was investigated using the fluorescence (FL) based pyrene method. Micelle formation was feasible owing to the relatively long hydrophobic chains and increased hydroxyl groups in the preservative molecules. The emulsification capability of the preservative was assessed using the Rosano and Kimura method, showing that the preservative possessed emulsifying capability in an organic solvent (benzene) and soy bean oil. In addition, the dispersion stability of cosmetic formulations, including the new LB preservatives such as essence and lotion, was demonstrated by comparing the light transmittance of the formulations. This article provides important information for future research regarding the synthesis and practical applications of new toxic-free naturally derived preservatives.

• Macromolecular Research
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• v.14 no.5
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• pp.573-578
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• 2006

Three different, polymer-platinum conjugates (hydrogels, microparticles, and nanoparticles) were synthesized by complexation of cis-dichlorodiammineplatinum(II) (cisplatin) with partially succinylated glycol chitbsan (PSGC). Succinic anhydride was used as a linker to introduce cisplatin to glycol chitosan (GC). Succinylation of GC was investigated systematically as a function of the molar ratio of succinic anhydride to glucosamine, the methanol content in the reaction media, and the reaction temperature. By controlling the reaction conditions, water-soluble, partially water-soluble, and hydrogel-forming PSGCs were synthesized, and then conjugated with cisplatin. The complexation of cisplatin with water-soluble PSGC via a ligand exchange reaction of platinum from chloride to the carboxylates induced the formation of nano-sized aggregates in aqueous media. The hydrodynamic diameters of PSGC/cisplatin complex nano-aggregates, as determined by light scattering, were 180-300 nm and the critical aggregation concentrations (CACs), as determined by a fluorescence technique using pyrene as a probe, were $20-30{\mu}g/mL$. The conjugation of cisplatin with partially water-soluble PSGC, i.e., borderline between water-soluble and water-insoluble PSGC, produced micro-sized particles $<500{\mu}m$. Cisplatin-complexed PSGC hydrogels were prepared from water-insoluble PSGCs. All of the cisplatin-incorporated, polymer matrices released platinum in a sustained manner without any significant initial burst, suggesting that they may all be useful as slow release systems for cisplatin. The release rate of platinum increased with the morphology changes from hydrogel through microparticle to nanoparticle systems.

• Journal of Adhesion and Interface
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• v.14 no.1
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• pp.13-20
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• 2013

Palladium plays a pivotal role in the production of dental and medicinal devices, medicinal substances, jewellery, automobile and high-performance adhesives. Despite the frequent and fruitful use of such reactions, one major setback is the high level of palladium in the resultant compounds which can harm the human body. Among the palladium species, $PdCl_2$ is the most toxic. As a consequence it is desirable to detect the $Pd^{2+}$ cations by fluorescence spectra because it can provide an operationally simple and cost-effective detection method together with high sensitivity and selectivity. Herein, an ${\alpha}$-carbonyl substituted pyrene derivative, ${\gamma}$-oxo-1-pyrenebutyric acid (OPBA), was demonstrated to be a highly sensitive and selective fluorescent probe for $Pd^{2+}$ among the metal cations examined in aqueous solutions.

• Analytical Science and Technology
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• v.20 no.2
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• pp.170-175
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• 2007

To determine levels of benzopyrene in olive oils, a selective analytical method of HPLC/FLD has been applied. After removing fat in food samples with hexane, it was extracted in aqueous N,N-DMF solution, cleaned-up on florisil SPE cartridge and analyzed by the instrumental analysis. The mobile phase was a mixture of acetonitrile and water in 8:2 by the isocratic elution and the excitation wavelength of fluorescence detector was 294 nm and emission wavelength of it was 404 nm. The average recovery was about 95 % and the limit of quantitation was $0.9{\mu}g/kg$. The levels of benzopyrene in the selected olive oil samples were ranged from not detected to $1.9{\mu}g/kg$, however, they were under $2.0{\mu}g/kg$, the maximum level of benzopyrene in olive oil which was established in the food code.

• Environmental Mutagens and Carcinogens
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• v.22 no.4
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• pp.303-311
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• 2002

This study evaluated the concentrations of urinary metabolites of polycyclic aromatic hydrocarbons (PAHs) in industrial waste incineration workers. The effect of genetic polymorphisms of xenobiotic metabolism enzymes on urinary concentration of PAH metabolites was assessed. And, aromatic DNA adduct levels were also determined in total white blood cells. Fifty employees were recruited from a company handling industrial wastes located in Ansan, Korea: non-exposed group (n=21), exposed group (n=29). Sixteen ambient PAHs were determined by GC/MSD (NIOSH method) from personal breathing zone samples of nine subjects near incinerators. Urinary 1-hydroxypyrene glucuronide (1-OHPG), a major pyrene metabolite, was assayed by synchronous fluorescence spectroscopy after immunoaffinity purification using monoclonal antibody 8E11 (SFS/IAC). Multiplex PCR was used for genotyping for GSTMI/TI and PCR-RFLP for genotyping of CYP1A1 (MspI and Ile/Val). PAH-DNA adducts in peripheral blood WBC were measured by the nuclease P1-enhanced postlabeling assay. Smoking habit, demographic and occupational information were collected by self-administered questionnaire. The range of total ambient PAH levels were 0.00-7.00 mg/㎥ (mean 3.31). Urinary 1-OHPG levels were significantly higher in workers handling industrial wastes than in those with presumed lower exposure to PAHs (p=0.006, by Kruskal-Wallis test). There was a statistically significant dose-response increase in 1-OHPG levels with the number of cigarettes consumed per day (Pearson correlation coefficient=0.686, p<0.001). Urinary 1-OHPG levels in occupationally exposed smoking workers were highest compared with non-occupationally exposed smokers (p=0.053, by Kruskal-Wallis test). Smoking and GSTMI genotype were significant predictors for log-transformed 1-OHPG by multiple regression analysis (overall model R²=0.565, p<0.001), whereas smoking was the only significant predictor for log-transformed aromatic DNA adducts (overall model R²=0.249, p=0.201). Aromatic DNA adducts was also a significantly correlation between log transferred urinary 1-OHPG levels (pearson's correlation coefficient=0.307, p=0.04). However, the partial correlation coefficient adjusting for Age, Sex, and cigarette consumption was not significant (r=0.154, p=0.169). The significant association exists only in individuals with the GSTMI null genotype (pearsons correlation coefficient=0.516, p=0.010; partial correlation coefficient adjusting for age, sex, and cigarette consumption, r=0.363, p=0.038). Our results suggest that the significant increase in urinary 1-OHPG in the exposed workers is due to higher prevalence of smokers among them, and that the association between urinary PAH metabolites and aromatic DNA adducts in workers of industrial waste handling may be modulated by GSTMI genotype. There results remain to be confirmed in future larger studies.

• Journal of Pharmacopuncture
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• v.19 no.1
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• pp.37-44
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• 2016

Objectives: This study examined the relative efficacies of a derivative of betulinic acid (dBA) and its poly (lactide-co-glycolide) (PLGA) nano-encapsulated form in A549 lung cancer cells in vivo and in co-mutagen [sodium arsenite (SA) + benzo[a]pyrene (BaP)]-induced lung cancer in mice in vivo. Methods: dBA was loaded with PLGA nanoparticles by using the standard solvent displacement method. The sizes and morphologies of nano-dBA (NdBA) were determined by using transmission electron microscopy (TEM), and their intracellular localization was verified by using confocal microscopy. The binding and interaction of NdBA with calf thymus deoxyribonucleic acid (CT-DNA) as a target were analyzed by using conventional circular dichroism (CD) and melting temperature (Tm) profile data. Apoptotic signalling cascades in vitro and in vivo were studied by using an enzyme-linked immunosorbent assay (ELISA); the ability of NdBA to cross the blood-brain barrier (BBB) was also examined. The stage of cell cycle arrest was confirmed by using a fluorescence-activated cell-sorting (FACS) data analysis. Results: The average size of the nanoparticles was ~ 110 nm. Confocal microscopy images confirmed the presence of NdBA in the cellular cytoplasm. The bio-physical properties of dBA and NdBA ascertained from the CD and the Tm profiles revealed that NdBA had greater interaction with the target DNA than dBA did. Both dBA and NdBA arrested cell proliferation at G0/G1, NdBA showing the greater effect. NdBA also induced a greater degree of cytotoxicity in A549 cells, but it had an insignificant cytotoxic effect in normal L6 cells. The results of flow cytometric, cytogenetial and histopathological studies in mice revealed that NdBA caused less nuclear condensation and DNA damage than dBA did. TEM images showed the presence of NdBA in brain samples of NdBA fed mice, indicating its ability to cross the BBB. Conclusion: Thus, compared to dBA, NdBA appears to have greater chemoprotective potential against lung cancer.