This work evaluated derivatization procedures for detecting both natural and synthetic estrogenic chemicals by gas chromatography/mass spectrometry (GC/MS). Different silylating agents, mainly trimethylsilylating (TMS) agents, were compared, and the roles of various content of trimethylchlorosilane (TMCS, as a stimulator) were investigated. The difference in the abundances of the derivatives was caused by the steric hindrance of multiple hydroxyl groups and ethynyl groups in the structures of estrogenic chemicals. The use of TMCS produces an increase in the derivatization yield, especially for the compounds with multiple hydroxyl groups (i.e., 17beta-estradiol (E(2)) and estriol (E(3))). Mass spectra of O-TMS derivatives and tentative fragmentation profiles are proposed. Molecular ions were the base peaks for all the derivatives, and were used as the quantitation ions to obtain maximum detection sensitivity and specificity. Sample enrichment was achieved by Oasis HLB solid-phase extraction cartridges. The quantitation limits of these compounds ranged from 5 to 10 ng/L in 1000-mL water samples. Recovery of the estrogenic chemicals in spiked various water samples ranged from 78 to 102% while relative standard deviation (RSD) ranged from 1 to 15%.
Thin films with the high content of Ti coated on the stainless steel (SS) sieves were successfully prepared through the sol gel method. Photocatalytic reaction on the TiO2-coated SS sieves with UVA (ultraviolet light with the range of 315-400 nm) radiation is effective to destroy three selected bacterial strains with log-phase period. As a result, bactericidal ability was achieved to 77% in aqueous media. Amount of bacterial numbers, 3.4×107CFU/ml can be removed in this study, compared with our previous study, 1.85×103CFU/ml in the air media. Good contribution of bactericidal ability in 385 nm UVA radiation or heavy metals including Fe, Mn, Cr, Ni and Ti from the SS sieve was obtained as the range of 30-76%. The percentage of 10-17% contribution of bactericidal ability was increased with the photocatalytic reaction additive. It concluded the performance of bactericidal ability in aqueous solution is ascribed to the combination of UVA radiation, heavy metals on the sieve and photocatalytic reaction. The SS sieve coated with TiO2particles can be applied as a disinfectant for the effluent of wastewater treatment plant or water supply system in the future.
Magnetic photocatalystic particles (MPCs) become an alternative process for water and wastewater treatment due to the high removal rate of organic pollutants and a good recovery. Little information of MPCs on the control of microorganisms was obtained in previous researches. In this study, the synthesized MPCs combined with 365 nm UVA irradiation under a light of 1.0 mW/cm2were applied to control a typical gram-negative strain Staphylococcus sciuri (99% Identified by the NCBI website), which was isolated from an indoor traditional market in the middle area of Taiwan. As a result, the highest bactericidal efficiency (BE) of MPCs contained 0.50 g magnetic particles in nutrient broth was achieved to 68.18% at 50 mins. Considering to each contribution of bacterial control, UVA irradiation played an important role of BE increased from 34.88% at 10 mins to 63.64% at 50 mins. Photocatalystic reaction provided extra more 11.02% of BE at initial 20 mins. The synthesized MPCs demonstrated good crystallinity of anatase by SEM-EDS and XRF. The 76% MPCs can be recovered by simple magnets after photocatalystic reaction.
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