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1.
三氯生的光降解产物分析及相关日化产品的安全性研究 总被引:2,自引:0,他引:2
采用气相色谱-质谱联用法(GC-MS)和高效液相色谱法(HPLC)(PAD检测器)对三氯生的光降解产物进行了分析,同时考查日化产品(牙膏、洗手液)中三氯生的安全性。光解反应是通过在紫外灯(UVB,15W)下直接照射三氯生溶液来完成的。HPLC的分离条件为:以Symmetry C18(5μm,4.6mm i.d.×250mm)为色谱柱,95%的甲醇溶液为流动相(H3PO4调节pH至5),外标法定量测定其降解产物2,8-二氯代二苯并-对-二口恶英(2,8-DCDD)。结果表明,2,8-DCDD在三氯生的光照溶液中被检测到,而在日化产品牙膏和洗手液中未被发现。本法可对2,8-DCDD进行定性和定量测定,便于对一些日化产品的监控。 相似文献
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《高等学校化学学报》2015,(9)
以模拟太阳光为照射光源,对冰相中苯酚在过氧化氢(H2O2)存在条件下的光转化反应进行了研究,考察了影响苯酚光转化反应的主要因素并探讨了光转化动力学过程.研究结果表明,光强度越高或H2O2初始浓度越大,苯酚在冰相介质中的光转化率越快,而苯酚初始浓度越高则会导致苯酚的光转化率减慢.p H值对苯酚的光转化率的影响则表现为酸性导致减小,碱性导致加快.应用气相色谱-质谱联用仪(GC-MS)分析了苯酚的光解产物,推断苯酚在冰相中的光解过程中主要发生了羟基化反应. 相似文献
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单组分可见光引发剂是光固化材料研发中的重要内容。本文设计并合成了一种新型的单组分可见光引发剂——2-硫杂蒽酮乙酸四苯基磷酸盐(TXP),该引发剂以硫杂蒽酮为生色团,通过光致脱羧反应产生活性自由基,进而引发聚合反应。利用核磁和高分辨率质谱对TXP的结构进行了表征;通过光解及电子自旋共振捕获等方法研究了其光致脱羧反应。光聚合动力学研究表明:在可见光源照射下,这种单组分光引发剂能高效引发巯基-烯类单体的聚合反应,具有一定的应用的前景。 相似文献
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新型光引发剂硫代苯甲酸一S一苯酷对烯类单体的聚合具有很高的引发效率,因而被应用于快速光聚合体系中,硫代苯甲酸一S一苯醋的光解产物经气相色谱和气/质联用仪鉴定,有苯硫酚、苯甲醛、二苯基硫醚、二苯基二硫醚、联苯、光Flies重排产物即邻琉基苯甲酞基苯和对琉基苯甲酞苯等七种,光解产物中笼内/笼外产物的比例受介质和外加磁场的影响显著:在“溶剂笼”中光解时,笼外产物占优势,在结构较溶剂笼紧密的硅胶板上光解时,笼内产物占优势,当有外加弱磁锡时,笼外产物比例上升说明硫代苯甲酸-S-苯酷的光解是通过三重激发态而发生的. 相似文献
6.
化学发光法测定三氯生 总被引:1,自引:0,他引:1
1引言三氯生(2,4,4′-三氯-2-羟基二苯醚)是常用消毒剂,广泛应用于日化产品中。三氯生的大量应用,对河流、湖泊等带来的污染问题受到关注。另外,三氯生合成过程中还可能产生有害的二噁英类物质。定量测定日化产品中三氯生的方法报道较少,有电化学法、高效液相色谱法、紫外分光光度法、毛细管区带电泳法等,未见有化学发光法测定三氯生的报道。研究表明,在荧光素存在下三氯生溶液经光照后,可与氧化剂反应产生化学发光。曲拉通X-100可极大地增强化学发光信号。据此建立了三氯生的化学发光测定新方法。2实验部分2.1仪器与试剂IFFM-D型流动注… 相似文献
7.
本文设计并制备了以香豆素并咔唑为共轭结构的草酸酯类光引发剂(2-OAME和4-OAME),分子中大π-共轭结构的引入实现了分子在LED光域的良好吸收。通过核磁共振谱对目标产物进行了结构验证,通过紫外-可见吸收光谱、荧光光谱和理论计算对分子的光化学及光物理性质进行了表征。研究表明,两个光引发剂在近紫外-可见光范围内均表现出优异的光吸收性质,并且在LED光源激发下具有良好的光引发聚合能力,4-OAME分子较2-OAME在同样的条件下表现出更好的光引发聚合能力,在近紫外-可见LED光聚合领域具有较大的应用潜力。 相似文献
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以环戊二烯基异丙苯铁六氟磷酸盐为光引发剂,用等温差示扫描量热法(DSC)研究了对甲苯基缩水甘油醚(CGE)的光引发阳离子聚合的温度效应及聚合反应动力学。研究表明CGE聚合时,反应速率及最终转化率随温度变化在550℃及450℃左右有一个峰值。CGE光聚合反应速率与单体浓度的一次方成比例,其反应机理包括两个基本反应,即:引发剂光解产物与单体的配合反应以及在该配合物中单体的开环反应,而这两个反应具有相反的温度效应,升高温度有利于后者而不利于前者。 相似文献
11.
Jian‐lin Wu Jie Liu Zongwei Cai 《Rapid communications in mass spectrometry : RCM》2010,24(13):1828-1834
Triclosan is a widely used broad‐spectrum antibacterial agent that acts by specifically inhibiting enoyl–acyl carrier protein reductase. An in vitro metabolic study of triclosan was performed by using Sprague‐Dawley (SD) rat liver S9 and microsome, while the in vivo metabolism was investigated on SD rats. Twelve metabolites were identified by using in‐source fragmentation from high‐performance liquid chromatography/negative atmospheric pressure chemical ionization ion trap mass spectrometry (HPLC/APCI‐ITMS) analysis. Compared to electrospray ionization mass spectrometry (ESI‐MS) and tandem mass spectrometry (MS/MS) that gave little fragmentation for triclosan and its metabolites, the in‐source fragmentation under APCI provided intensive fragmentations for the structural identifications. The in vitro metabolic rate of triclosan was quantitatively determined by using HPLC/ESI‐ITMS with the monitoring of the selected triclosan molecular ion. The metabolism results indicated that glucuronidation and sulfonation were the major pathways of phase II metabolism and the hydroxylated products were the major phase I metabolites. Moreover, glucose, mercapturic acid and cysteine conjugates of triclosan were also observed in the urine samples of rats orally administrated with triclosan. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
12.
Canosa P Morales S Rodríguez I Rubí E Cela R Gómez M 《Analytical and bioanalytical chemistry》2005,383(7-8):1119-1126
The degradation of 2-(2,4-dichlorophenoxy)-5-chlorophenol (triclosan) in chlorinated water samples was investigated. Sensitive
determination of the parent compound and its transformation products was achieved by gas chromatography with mass spectrometry
detection after sample concentration, using a solid-phase extraction sorbent and silylation of the target compounds. Experiments
were accomplished using ultrapure water spiked with chlorine and triclosan concentrations in the low mg/l and ng/ml ranges
respectively. Chlorination of the phenolic ring and cleavage of the ether bond were identified as the main triclosan degradation
pathways. Both processes led to the production of two tetra- and a penta-chlorinated hydroxylated diphenyl ether, as well
as 2,4-dichlorophenol. The formation of 2,3,4-trichlorophenol was not detected in any experiment; however, significant amounts
of 2,4,6-trichlorophenol were noticed. All of these five compounds were also identified when triclosan was added to tap-water
samples with free chlorine concentrations below 1 mg/l. Minor amounts of three di-hydroxylated phenols, containing from one
to three atoms of chlorine in their structures, were also identified as unstable triclosan chlorination by-products. The analysis
of several raw wastewater samples showed the co-existence of important concentrations of triclosan and its most stable by-products
(2,4-dichlorophenol and 2,4,6-trichlorophenol), reinforcing the potential occurrence of the described transformations when
products containing triclosan are mixed with chlorinated tap water. 相似文献
13.
Jermiah Y. Shen Matt S. Chang Sheng‐Hsiung Yang Gaston J. Wu 《Journal of separation science》2012,35(19):2544-2552
The presence of triclosan and triclocarban, two endocrine‐disrupting chemicals and antimicrobial agents, and transformation products of triclocarban, 1,3‐di(phenyl)urea, 1,3‐bis(4‐chlorophenyl)urea and 1,3‐bis(3,4‐dichlorophenyl)urea, in tap water, treated household drinking water, bottled water, and river water samples were investigated using solid‐phase micro‐extraction coupled with‐HPLC‐MS/MS, a rapid, green, and sensitive method. Factors influencing the quantity of the analytes extracted onto the solid‐phase micro‐extraction fiber, such as addition of salt, sample pH, extraction time, desorption time, and sample volume, were optimized using solid‐phase micro‐extraction‐HPLC‐MS/MS. The results showed that the method gave satisfactory sensitivities and precisions for analyzing sub‐part‐per‐trillion levels of triclosan, triclocarban, and transformation products of triclocarban in samples collected locally. The recoveries of analytes ranged from 97 to 107% for deionized water samples, and 99 to 110% for river water samples, and limits of detection were in the range of 0.32–3.44 and 0.38–4.67 ng/L for deionized water and river water samples, respectively. On average, the daily consumption of triclosan and triclocarban by an adult by consuming 2 liters of different types of drinking water were estimated to be in the range of 6.13–425 ng/day as a result of the concentrations of triclosan and triclocarban measured in this study. 相似文献
14.
Claisen rearrangement of allyl phenyl ether and its sulfur and selenium analogues on electron impact
Prabhakar S Mirza SP Kundu A Roy S Vairamani M 《Rapid communications in mass spectrometry : RCM》2000,14(13):1116-1122
The electron impact (EI) mass spectrum of allyl phenyl ether (1) includes an ion at m/z 106 that is formed mainly by the loss of CO from the molecular ion, as supported by high resolution and MS/MS data. The formation of the [M - CO](+) ion from 1 can be explained in terms of the Claisen rearrangement of 1 after ionization in the ion source of the mass spectrometer. Similarly, allyl phenyl sulfide (2) and allyl phenyl selenide (3) showed characteristic ions corresponding to [M - CH(3)](+), [M - XH](+) (X = S or Se) and [M - C(2)H(4)](+.), and the formation of these ions are explained via Claisen rearrangement of 2 and 3 in the ion source of the mass spectrometer resulting in a mixture of rearrangement products. The formation of molecular ions of 2-allyl thiophenol and 2-allyl selenophenol as intermediates, that cannot be isolated as the neutrals from the solution phase Claisen rearrangement of 2 and 3, respectively, is clearly indicated in the gas phase. The mass spectra of the rearrangement products obtained from the solution phase reaction were also consistent with the proposal of formation of these products in the ion source of the mass spectrometer. The formation of characteristic fragment ions attributed to the Claisen rearrangement products are also evident in the collision induced dissociation spectra of the corresponding molecular ions. Copyright 2000 John Wiley & Sons, Ltd. 相似文献
15.
The rearrangement of N-p-toluenesulfonyl 2-tert-butyldiphenylsilylmethyl-substituted azetidines into 3-tert-butyldiphenylsilyl-substituted pyrrolidines under Lewis acid conditions in dichloromethane involves 1,2-migration of silicon through a siliranium ion. The formation of siliranium ion was discovered not to be in concert with σ(C-N) cleavage from stereochemical analysis of the pyrrolidine products formed from 3- and 4-substituted-2-tert-butyldiphenylsilylmethyl azetidines and also from the optical rotation data and chiral HPLC analysis of the pyrrolidine product formed from N-p-toluenesulfonyl 2(R)-tert-butyldiphenylsilylmethyl azetidine. The formation of sterically less hindered siliranium ion is followed by its S(N)2 opening by the internal nitrogen nucleophile. Oxidative cleavage of σ(C-Si) bond leads to the formation of 3-hydroxypyrrolidines. 相似文献
16.
Kanawati B Herrmann F Joniec S Winterhalter R Moortgat GK 《Rapid communications in mass spectrometry : RCM》2008,22(2):165-186
The components of the organic aerosol formed due to gas-phase beta-caryophyllene ozonolysis were characterized by the use of a triple quadrupole and time-of-flight analyzer hybrid system coupled to an electrospray ionization source operated in the negative ion mode. A reversed-phase high-performance liquid chromatography (HPLC) column was used to achieve chromatographic separations at neutral pH which has been proved to induce ionization of organic compounds bearing aldehyde moieties. In addition to the detected oxo- and dicarboxylic acids, isomeric oxidation products, which bear multi-functional groups such as aldehyde, carbonyl and hydroxyl groups, could be differentiated by examining their corresponding collision-induced dissociation (CID) fragmentation pathways. Proposed fragmentation mechanisms were drawn for the experimentally observed fragmentation pathways in all the CID experiments. Cyclic oxidation products could also be discerned and their fragmentation behaviour under low energy collisional conditions was studied in detail. Gas-phase deprotonation potentials were calculated by the use of DFT B3LYP/6-311+G(2d,p)//B3LYP/6-31+G(d) + ZPVE to estimate the most thermodynamically favourable deprotonation site for efficient negative ion formation in the ion source. The optimized gas-phase geometries for the most prominent oxidation products reveal a strong intramolecular interaction between the upper and lower C4 carbon chains, which are formed after the decomposition of the primary ozonide generated by ozone attack of the reactive endocyclic C==C bond. 相似文献
17.
Sánchez-Prado L Llompart M Lores M Fernández-Alvarez M García-Jares C Cela R 《Analytical and bioanalytical chemistry》2006,384(7-8):1548-1557
In this study the photoinduced degradation of triclosan has been investigated by photo-solid-phase microextraction (photo-SPME). In photo-SPME, photodegradation is carried out on the SPME fibre containing the target compound. Triclosan was extracted from aqueous solutions by use of polydimethylsiloxane SPME fibres and these were subsequently exposed to UV irradiation (power 8 W, wavelength 254 nm) for different times (from 2 to 60 min). The photodegradation kinetics of triclosan were investigated, the photoproducts generated were tentatively identified, and the photochemical behaviour of these products was studied by use of this on-fibre approach followed by gas chromatographic–mass spectrometric analysis. Eight photoproducts were tentatively identified, including chlorinated phenols, chlorohydroxydiphenyl ethers, 2,8-dichlorodibenzo-p-dioxin, and a possible dichlorodibenzodioxin isomer or dichlorohydroxydibenzofuran. The main photodegradation mechanisms were postulated and photodegradation pathways proposed. The effect of pH on triclosan degradation and on triclosan-to-dioxin conversion was also investigated. Triclosan degradation occurred, and generation of 2,8-dichlorodibenzo-p-dioxin was confirmed, throughout the pH range studied (from 3 to 9).
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The formation of 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) in the photolytic degradation of triclosan has evoked a great concern for its safety and environmental
fate. The photochemical behaviour of triclosan in daily-used chemical products, in which triclosan is present in relatively
high concentrations and coexists with surfactants, was, however, addressed less frequently. The present work is focused on
the mechanistic aspects of triclosan photodegradation in an aqueous medium with a relatively high concentration (≥ 30 mg L−1) and on the influence of pH (8.7 and 10.5) and surfactants (Triton X100, SDS, and CTMAB) on this process. The results demonstrated
that photodegradation was strongly affected by the pH and the presence of surfactants. Photodegradation products, including
2,4-dichlorophenol (2,4-DCP), 5-chloro-2-(4-chlorophenoxyl)-phenol, 2,8-DCDD, dimers, trimers, and other intermediates, were
identified. Based on the analysis of photoproducts, homolytic scission of ether bond, dechlorination, ring closure, and photo-polymerisation
were proposed as the main routes of triclosan photodegradation. 相似文献
19.
Gavryushov S 《The journal of physical chemistry. B》2007,111(19):5264-5276
Potentials of mean force between single Na+, Ca2+, and Mg2+ cations and a highly charged spherical macroion in SPC/E water have been determined using molecular dynamics simulations. Results are compared to the electrostatic energy calculations for the primitive polarization model (PPM) of hydrated cations describing the ion hydration shell as a dielectric sphere of low permittivity (Gavryushov, S.; Linse, P. J. Phys. Chem. B 2003, 107, 7135). Parameters of the ion dielectric sphere and radius of the macroion/water dielectric boundary were extracted by means of this comparison to approximate the short-range repulsion of ions near the interface. To explore the counterion distributions around a simplified model of DNA, the obtained PPM parameters for Na+ and Ca2+ have been substituted into the modified Poisson-Boltzmann (MPB) equations derived for the PPM and named the epsilon-MPB (epsilon-MPB) theory. epsilon-MPB results for DNA suggest that such polarization effects are important in the case of 2:1 electrolyte and highly charged macromolecules. The three-dimensional implementation of the epsilon-MPB theory was also applied to calculation of the energies of interaction between two parallel macromolecules of DNA in solutions of NaCl and CaCl2. Being compared to results of MPB calculations without the ion polarization effects, it suggests that the ion hydration shell polarization and inhomogeneous solvent permittivity might be essential factors in the experimentally known hydration forces acting between charged macromolecules and bilayers at separations of less than 20 A between their surfaces. 相似文献
20.
三氯生是一种被广泛应用在家庭卫生用品中的抗菌消毒剂。虽然其本身不具有很强的毒性,但其在生物体内的代谢变化是否对生物和人体有害我们还不得而知。因此,研究三氯生在动物体内的代谢与动力学情况是具有重要意义的。本文采用超高效液相色谱串联三级四极杆质谱法来测定口服给药(5 mg/kg)后大鼠血浆中的三氯生的含量及其代谢产物。相对于多反应监测(MRM)技术,尽管其有较好的最低检测限,但选择离子监测(SIR, 又称为SIM)有更好的方法验证参数。在本试验中,选择离子监测方法检测限为10.8 ng/mL,方法的回收率、准确度、精密度和重现性都较高。用该方法测定的三氯生在大鼠体内的消除半衰期为(48.5±10.5) h。同时,还鉴定出其三氯生血浆中有分别被羟基化加磺酸化、葡萄糖醛酸化以及磺酸化的4个代谢产物。 相似文献