• 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.

• Journal of the Korean Applied Science and Technology
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• v.24 no.3
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• pp.309-318
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• 2007

Novolac is widely used as the primary solid component of most photoresists in semiconductor and microelectronic devices. In this study, novolac resins were prepared by condensation of 35% formaldehyde with phenolic compounds such as m-/p-cresol, 2,5-dimethylphenol and bisphenol A in the presence of oxalic acid as catalyst. The average molecular weight $(M_w)$ of these novolac resins has been varied on the changing of mixing ratio of m-/p-cresol/2,5-dimethylphenol/bisphenol A or formaldehyde/phenolic compound. Also, thermal properties of novolac were observed by TGA.

• Environmental Mutagens and Carcinogens
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• v.24 no.1
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• pp.25-32
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• 2004

To validate and to estimate the chemical hazard playa very important role to environment and human health. The detection of many synthetic chemicals used in industry that may pose a genetic hazard in our environment is of great concern at present. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of chemicals that possibly threaten the public health. In this resepct, the clastogenicity of 17 synthetic chemicals was evaluated with bone marrow micronucleus assay in mice. The positive control, mitomycin C (2 mg/kg, i.p.) revealed significant induction ratio of percentage of micronucleated polychromatic erythrocytes/1,000 polychromatic erythrocytes compared to solvent controls. The chemicals with relatively high $LD_{50}$ value such as allyl alcohol (CAS No. 107-18-6), 2,4-pentanedione (CAS No. 123-54-6) and 4-chloro-3,5-dimethylphenol (CAS No. 88-04-0) revealed no significant induction of micronucleated polychromatic erythrocytes in mice. From this results, 17 synthetic chemicals widely used in industry have revealed no significant micronucleus induction of clastogenicity in mice in this experiment.

• Analytical Science and Technology
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• v.17 no.5
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• pp.393-400
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• 2004

Nitrosation of phenol (POH) was studied by adding hydrochloric acid and sodium nitrite to phenol solution with reaction temperature and time change. The optimum condition of nitrosation was found from the effects of hydrochloric acid and sodium nitrite concentration, reaction temperature, and reaction time changes on the production of nitrosophenol (POHNO). As a result, it was found that the optimum conditions were $5.0{\times}10^{-4}{\sim}2.0{\times}10^{-3}M$ range of $NO{_2}^-$ concentration, more than 0.10 M of HCl concentration, temperature of $80^{\circ}C$, and 3 hrs. of reaction time. In this condition, 10 U.S. E.P.A. classified priority environmental pollutant, phenols, were nitrosated. Nitrosated phenols were: POH, 2-Chlorophenol (2ClPOH), 2,4-diChlorophenol (2ClPOH), 2,4-dimethylphenol (24diMPOH), and 4-Chloro -3-methylphenol (4Cl3MPOH), and a small part of 2-nitrophenol (2NPOH). The ${\lambda}_{max}$ values of nitrosated phenols in acidic solution were around 300 nm, and those in basic solution were around 400 nm. Molar absorptivities (${\varepsilon}$) at the 400 nm of the nitrosated phenols in the basic solution were 1.5~2.0 times larger than those at 300 nm in acidic solution. It was also found by Capillary-HPLC chromatograms of the nitrosated phenol solutions that the production of the nitrosophenols were interfered by the excess concentration of nitrite (more than $3.0{\times}10^{-3}M$).