食品用洗涤剂中1,4-二噁烷含量检测研究进展

对食品用洗涤剂中二(噁)烷含量的检测技术和样品前处理方法进行了概述.预见顶空-固相微萃取-气相色谱-串联四极杆技术必将对洗涤剂中的1,4-二(噁)烷含量测定起到积极作用.     

固相微萃取新型活性炭涂层萃取头的研究

利用合成的有机硅树脂胶粘剂和活性炭微粉首次制成活性涂层萃取头。通过苯系物(BTEX)表征了涂层表观结构、厚度及萃取性能。对苯、甲苯、乙苯、对二甲苯、邻二甲苯等进行固相微萃取,结果表明:该萃取头热稳定性好,最高使用温度可达290℃;使用寿命长,250℃解吸条件下反复使用140余次以后,膜层没有脱落或性能下降的现象。该涂层对苯系物的最低检出质量浓度在0 21～0 94μg L之间。与100μm的商品聚二甲基硅氧烷(PDMS)涂层相比,对苯系物的富集能力整体上相当。     

顶空固相微萃取-气相色谱法测定生活饮用水中痕量1,4-二氧六环

建立了生活饮用水中痕量1,4-二氧六环的顶空固相微萃取(HS/SPME)-气相色谱测定方法。考察并优化了萃取头、萃取温度、萃取时间、pH值、样品量、色谱条件等参数。结果表明:提取效率较好的方法是3 mL水样中加入3 mL 600 g/L氢氧化钠溶液,用85 μm Carboxen-PDMS萃取头萃取,用键合碱改性的大口径、厚液膜PTA-5毛细管色谱柱测定。1,4-二氧六环在0.50~50.0 μg/L范围内线性关系良好,相关系数为0.9995;方法检出限(以S/N>3计)为0.14 μg/L;相对标准偏差为2.1%~4.5% (n=6);对实际样品中进行线性范围内的高、中、低3个加标水平的测定,回收率为95.5%~107%,相对标准偏差为1.1%~5.3% (n=6)。建立的方法简便、准确、重现性好、灵敏度高,适合生活饮用水中痕量1,4-二氧六环的常规监测。     

十二甲基六元瓜环包结1,4-二烷噁的晶体结构

合成了全甲基取代六元瓜环(Me_(12)Q[6])与1,4-二噁烷的包结配合物并生长了晶体,通过单晶X-射线衍射方法进行了表征;该配合物形成了以Me_(12)Q[6]为"胶囊体"、1,4-二噁烷为"胶囊"芯材、水分子为"胶囊盖"的"分子胶囊"结构,"分子胶囊"通过氢键自组装形成一维超分子链,而一维的超分子链通过Me_(12)Q[6]端口的羰基氧原子与水分子之间的氢键作用横竖交错组成二维具有空洞结构的分子网.     

十二甲基六元瓜环包结1,4-二噁烷的晶体结构

合成了全甲基取代六元瓜环(Me12Q[6])与1,4-二噁烷的包结配合物并生长了晶体,通过单晶X-射线衍射方法进行了表征;该配合物形成了以Me12Q[6]为"胶囊体"、1,4-二噁烷为"胶囊"芯材、水分子为"胶囊盖"的"分子胶囊"结构,"分子胶囊"通过氢键自组装形成一维超分子链,而一维的超分子链通过Me12Q[6]端口的羰基氧原子与水分子之间的氢键作用横竖交错组成二维具有空洞结构的分子网。     

溴代十六烷吡啶从碱性氰化液中固相萃取金的研究

基于溴代十六烷吡啶(CPB)与Au(CN)2-络阴离子生成的离子缔合物可被反相键合硅胶固相萃取柱萃取、富集,建立了一种从碱性氰化液中高富集倍数固相萃取金的方法。在碱性介质中,溴代十六烷吡啶(CPB)与Au(CN)2-络阴离子生成离子缔合物,该离子缔合物可被反相键合硅胶固相萃取柱萃取、富集,富集的离子缔合物可用乙醇洗脱,洗脱液经处理后用分光光度法测定,反相键合硅胶固相萃取柱不被破坏而且可重复使用。方法用于从碱性氰化液中固相萃取痕量金,萃取回收率可超过98%,研究了反向固相萃取金的机理,同时提出了一种从碱性氰化液中提取金的新工艺。     

1,4-苯并二噁烷类新木脂素Eusiderin G的全合成

以没食子酸甲酯为原料,经过6步反应(总产率为24%),对1,4-苯并二噁烷类新? 局靥烊徊顴usiderinG进行了全合成。合成反应的关键是在强酸性离子交换? 髦呋拢肿幽诘拇剪腔敕郁腔浞⑸阉从Γ鼗沸纬?,4-苯并二噁烷骨架化合物。该合成路线具有简便易行、产率较高、副反应少的特点,可适用于其它具有生理活性的1,4-苯二噁烷类化合物的合成。     

Cu(Ⅰ)催化下2,3-二氢-1,4-苯并二噁烷类化合物的合成

以CuBr为催化剂,1,4,7-三氮杂环壬烷衍生物为配体,K₂CO₃为碱,110 ℃下通过取代的邻碘代酚和取代的环氧化物的串联反应制备了2,3-二氢-1,4-苯并二噁烷类化合物。各种芳香取代的环氧化物和脂肪取代的环氧化物均能顺利的与邻碘代酚反应,产物收率64%~83%。讨论了底物取代基与产物收率的关系,推测了反应机理。并用NMR和元素分析确定了产物结构。     

分子印迹固相微萃取测定中成药的鸟苷含量

用自制的分子印迹整体柱作固相微萃取介质,结合HPLC-UV装置,建立了中成药鸟苷成分的萃取检测方法。方法的线性范围为0.01～5.30μmol/L,检测限(LOD)为2.5 nmol/L(S/N=3),定量限(LOQ)9.0 nmol/L(S/N=10),样品加标回收率在94%～104%之间。方法已用于刺五加片、板蓝根冲剂及清热口服液等中成药鸟苷成分的检测。     

Determination of 1,4-Dioxane in Toluene by Gas Chromatography

A gas chromatographic method is presented for determining from 1 to 100 μg/mL of 1,4-dioxane in toluene with purities ranging from commercial to high-purity grades. This method relies on extracting 1,4-dioxane from toluene into water. The water extract is analyzed for 1,4-dioxane content by gas chromatography/flame ionization detection and a capillary column coated with a bonded polyethylene glycol stationary phase. Splitless injection is used to achieve a 1 μg/mL detection limit. Purging extracts with nitrogen after an initial analysis is suggested as an extract clean-up procedure and as a means to confirm the identification of 1,4-dioxane. However, for absolute identification of dioxane, gas chromatography/mass spectroscopy should be considered.     

A New Aluminium Hydroxide Coating on Fused Silica Fiber for the Determination of 1,4-Dioxane in Surfactants and Detergents Using HS-SPME-GC

This paper presents a simple and convenient analytical method for determination of 1,4-dioxane in surfactants and detergents by using a novel SPME fiber. For the preparation of the fiber, the surface of a fused silica capillary tubing was modified by means of aluminium tri-tert-butoxide in a straightforward grafting process. The surface of our proposed fiber provides a Lewis acid–base interaction with analyte functional groups. The main factors affecting the extraction were optimized by using a central composite design method, which leads to the following optimum conditions: extraction temperature of 34?°C, extraction time of 4?min, equilibrium time of 13?min, and salt content of 25% (w/v). The optimum conditions showed a linear range from 0.005 to 60?μg?g^?1. LOD and LOQ of the proposed method were estimated to be 0.0015 and 0.005?μg?g^?1, respectively. This method was also applied for the analysis of some real samples including ethoxylated fatty alcohol, sodium lauryl ether sulfate, dish-washing agents, and shampoos by using the standard addition method.     

顶空-气相色谱-质谱法测定皂、粉、液类洗涤用品中的二噁烷

提出了测定皂、粉、液类洗涤用品中二噁烷含量的顶空-气相色谱-质谱法。以5mL水为顶空溶剂,将样品在80℃顶空平衡50min后,经HP-5MS色谱柱分离,质谱检测器检测,外标法定量。3种基质中二噁烷的线性范围为0.1~50.0mg·kg-1,测定下限均在0.2mg·kg-1以下。以空白样品为基体进行加标回收实验,测得平均回收率在85.2%~97.8%之间,测定值的相对标准偏差(n=6)在2.6%~6.1%之间。     

在1,4-二氧六环介质中用导数三波长光度法同时测定抗菌优中各组分含量

本文提出了抗菌优(复方磺胺甲(口恶)唑)中磺胺甲基异(口恶)唑(SMZ)和甲氧苄胺嘧啶(TMP)两组分导数三波长同时测定的新方法。该法利用TMP在二氧六环中E_2带的增色效应和紫移作用以及UV-265光度计的指令链功能,达到了灵敏,准确、快速的目的。     

Excess Molar Volumes of n-Pentanol + Cumene,n-Pentanol + 1,4-Dioxane and Cumene + 1,4-Dioxane at Different Temperatures

Abstract

Molar excess volumes (V^E ) and partial molar excess volumes ( ^VE ) are reported for non-electrolyte binary mixtures of n-pentanol + cumene, n-pentanol + 1,4-dioxane and cumene + 1,4-dioxane at four temperatures and over the whole concentration range. In these systems, the n-pentanol is a highly polar molecule with association in its pure state, while the others two show little polarity without association in their pure states. The results of V^E are discussed in terms of the interactions between components. The Prigogine–Flory–Patterson model of solution thermodynamics has been used to predict V^E . This work shows the importance of the three contributions δV _int, δV _p? and δV_F to V^E .     

Synthesis of Optically Active 1,4-Dioxane Nucleotide Analogs

Optically active nucleotide analogs were prepared that were composed of a 1,4-dioxane ring as the sugar analog to which either uracil or adenine attached together with two carboxylic ester groups, to be used as vehicles for formation of oligomers. The chiral 1,4-dioxane moiety was constructed from dimethyl L-tartrate via the corresponding (2R,3R)-dimethyl 2-O-allyl-tartrate.     

Transition Metals and Organic Ligands Influence Biodegradation of 1,4-Dioxane

1,4-Dioxane, a contaminant increasingly detected in water supplies, is a public health concern because it is classified as a possible human carcinogen. 1,4-Dioxane can be biodegraded by aerobic bacteria via monooxygenase-catalyzed reactions. While these metalloenzymes require trace metals as cofactors in their catalytic sites, these metals may be toxic at elevated concentrations. In this study, the effects of transition metals on 1,4-dioxane biodegradation by Pseudonocardia dioxanivorans CB1190, a monooxygenase-expressing bacterium, were investigated. Dose-dependent inhibition of 1,4-dioxane biodegradation by Cd(II), Cu(II), and Ni(II) was observed, whereas Zn(II) had no measurable effect on biodegradation rates. 1,4-Dioxane biodegradation in cultures exposed to 2 mg/L Cu(II) was restored in the presence of 0.005, 0.05, and 0.5 mM alginin, 0.05, and 0.5 mM cysteine, and 0.005 mM tannin. These results indicated that specific ligands bind with transition metals and alleviate bacterial toxicity. In parallel experiments, tannin and cysteine inhibited 1,4-dioxane biodegradation, but alginin, BSA, and SRNOM did not affect the biodegradation rates. Thus, monooxygenase-catalyzed biodegradation rates are subject to interactions among transition metals and natural organic ligands in the environment. Mechanistic insights and quantitative data obtained in this study will be useful for designing bioremediation strategies at sites simultaneously contaminated with metals and organic pollutants.     

Dissociative Photoionization of 1,4-Dioxane with Tunable VUV Synchrotron Radiation

The photoionization and photodissociation of 1,4-dioxane have been investigated with a reflectron time-of-flight photoionization mass spectrometry and a tunable vacuum ultraviolet synchrotron radiation in the energy region of 8.0-15.5 eV. Parent ion and fragment ions at m/z 88, 87, 58, 57, 45, 44, 43, 41, 31, 30, 29, 28 and 15 are detected under supersonic conditions. The ionization energy of DX as well as the appearance energies of its fragment ions C₄H₇O₂⁺, C₃H₆O⁺, C₃H₅O⁺, C₂H₅O⁺, C₂H₄O⁺, C₂H₃O⁺, C₃H₅⁺, CH₃O⁺, C₂H₆⁺, C₂H₅⁺/CHO⁺, C₂H₄⁺ and CH₃⁺ was determined from their photoionization efficiency curves. The optimized structures for the neutrals, cations, transition states and intermediates related to photodissociation of DX are characterized at the B3LYP/6-31+G(d,p) level and their energies are obtained by G3B3 method. Possible dissociative channels of the DX are proposed based on comparison of experimental AE values and theoretical predicted ones. Intramolecular hydrogen migrations are found to be the dominant processes in most of the fragmentation pathways of 1,4-dioxane.     

自制苯乙烯-丙烯酸乙酯共聚物与PEG20M复合萃取涂层用于洗涤制品中1,4-氧杂环己烷的测定

采用顶空固相微萃取-毛细管气相色谱联用技术测定了洗涤制品中的1,4-二氧杂环己烷.使用自制的萃取头(苯乙烯-丙烯酸乙酯共聚物与PEG20M复合)于顶空平衡温度80℃下萃取样品40 min.萃取物用内壁涂有SE-30固定液的石英毛细管柱分离,外标法定量.1,4-二氧杂环己烷含量为0.35～120 μg/g时,其峰面积与含量呈良好的线性关系(r=0.999 8);回收率为98.7%～102%;相对标准偏差(n=5)为9.33%.