Summary: A polymeric photoinitiator (PTXP) containing in‐chain thioxanthone (TX) and coinitiator amines was synthesized by step‐growth polymerization, as well as low‐molecular‐weight model compounds. Photopolymerizations of methyl methacrylate (MMA) initiated by these photoinitiator systems were studied. Compared with corresponding low‐molecular‐weight model compounds, PTXP has a similar UV‐vis spectrum with a red‐shifted maximum absorption, and weaker fluorescence emission, and can photoinitiate the polymerization of MMA more effectively.
The structure of PTXP, the photoinitiator synthesized here. 相似文献
Chlorpromazine hydrochloride (CPZ) is a widely used anti-psychotic drug that induces skin photosensitization and photoallergy response after systematic use or topical applications. The photoallergic mechanism is still unknown. However, it has been proposed that the triplet excited state (3CPZ*) could participate in the photodamaging effects. In this work, we report the photophysical properties of the triplet excited state of CPZ and its parent derivative promazine hydrochloride (PZ) in the presence of 2-hydroxypropyl-β-cyclodextrin (HPC). Absorption measurements indicate that PZ and CPZ form an inclusion complex with HPC through a 1:1 stoichiometry. The equilibrium constant at 25 °C is (2.55 ± 0.09) × 103 M−1 and (3.27 ± 0.07) × 103 M−1 for PZ and CPZ, respectively. The CPZ and PZ triplet excited state properties changed in the presence of HPC. The triplet lifetime increases with HPC concentration that is related to the amount of drug bound. In addition, the triplet intersystem crossing quantum yield was determined to be 0.45 and 0.17 for PZ and CPZ, respectively, when more than 95% of the drug molecules are bound to HPC. Altogether, these results suggest that the microenvironment plays a crucial role in the 3CPZ* and 3PZ* properties and thus it can modulate their photosensitizing effects. 相似文献
Liquid chromatography–tandem mass spectrometry (LC-MS/MS) and gas chromatography–mass spectrometry (GC-MS) have been compared
for the analysis of 2-isopropyl thioxanthone (ITX) and 2-ethylhexyl-4-dimethylaminobenzoate (EHDAB). Pressurized liquid extraction
(PLE) was applied for the extraction of ITX and EHDAB from milk and milk-based beverages. Samples were homogenized with sea
sand and anhydrous sodium sulfate, and were extracted with ethyl acetate at 100 °C and 10.3 × 106 Pa in one cycle of 10 min at 90% flush. Both, GC-MS and LC-MS/MS were suitable to determine these photoinitiators in the
PLE extracts, providing appropriate identification and quantification. The recoveries obtained ranged from 70 to 99% for ITX
and from 70 to 95% for EHDAB. These recoveries were equal as those obtained by a conventional liquid–liquid partitioning with
acetonitrile and tert-butyl methyl ether–hexane. The quantification limits using GC-MS, based on a signal-to-noise ratio of 10, were 0.5 μg/L for
ITX and 1 μg/L for EHDAB. The repeatability of the method, as indicated by the relative standard deviations, was within the
range 0.9–16.1%. The same parameters calculated using LC-MS/MS result in quantification limits of 0.1 μg/L for ITX and 0.02 μg/L
for EHDAB and repeatability within the range 5.2–19.4%. These results pointed out that both techniques are appropriate to
determine these compounds in food samples. The method was applied to milk and milk-based beverages from different supermarkets.
The ITX and EHDAB contents ranged from 2.5 to 325 μg/L and from 8 to 126 μg/L, respectively.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
