β_2-SiW_(11)Mn/聚苯胺/ZnO三元复合材料的制备及其光催化性能

采用水浴加热方法制备β_2-SiW_(11)Mn/PANI/ZnO,用紫外光谱、热重、SEM方法进行表征。研究了合成的催化剂对有机染料甲基橙降解的光催化活性。讨论了催化剂用量、甲基橙溶液的初始质量浓度、溶液p H等对甲基橙降解的影响。结果表明,当溶液p H=8,催化剂用量25 mg/L,质量浓度为5 mg/L的甲基橙溶液在30 W紫外灯下,降解率可达99.63%,与催化剂β_2-SiW_(11)Mn和PANI/ZnO比较,三元催化剂β_2-SiW_(11)Mn/PANI/ZnO表现出更高的光催化降解性能。     

MCM-41负载酞菁铜光催化降解亚甲基蓝

利用浸渍法将金属酞菁1,4,8,11,15,18,22,25-八环戊氧基酞菁铜(α-CyOPcCu)负载到介孔分子筛MCM-41上,得到新型催化剂α-CyOPcCu/MCM-41,利用氮气吸附、红外光谱对催化剂的结构进行表征。研究催化剂用量和H_2O_2浓度对4 mg/L亚甲基蓝溶液降解效果的影响。当催化剂用量为0.6 g/L、H_2O_2浓度为0.6 mmol/L时,90 min后亚甲基蓝的降解率均可达99.6%。降解过程符合一级动力学特征,速率常数k=0.102 9 min~(-1)。该催化剂具有实用价值,循环使用3次降解率仍保持在95%以上。     

硅胶负载邻菲罗啉亚铁类Fenton降解水中罗丹明B

采用H2O2为氧化剂,自制硅胶负载邻菲罗啉铁(Ⅱ)配合物[Phen-Fe(Ⅱ)]为催化剂,对罗丹明B(Rh B)进行催化氧化降解.研究了催化剂质量比和用量、H2O2用量、反应温度和反应初始p H等因素对降解率的影响,并对Rh B的降解产物进行了初步分析.结果表明,对于20 mg/L Rh B溶液,当Phen-Fe(Ⅱ)催化剂质量比为1∶1,用量为3 g/L,H2O2用量为0.6 g/L,在40℃和初始p H=11.0的条件下降解6 h,其降解率可达70%.研究表明,Phen-Fe(Ⅱ)具有良好的催化效果.     

负载型催化剂α-PcCo/SBA-15光催化降解亚甲基蓝

采用浸渍法将α-八异戊氧基酞菁钴负载到SBA分子筛上制备了α-PcCo/SBA-15光催化剂。通过紫外、红外光谱和热重分析对产物进行了表征。在室温条件下,研究了催化剂用量和H2O2浓度对亚甲基蓝光催化降解效果的影响,并讨论了催化剂的重复使用情况。当催化剂用量为0.7 g/L,H2O2浓度为7 mmol/L时,6 mg/L亚甲基蓝在80 min的降解率达到了98.9%。催化剂重复使用3次后,降解率仍可以达到90.7%。催化反应符合一级反应动力学方程,速率常数为0.051 min-1。     

紫外LED点光源降解亚甲基蓝的动力学研究

为了研究点光源下亚甲基蓝废水的降解效率,探究了UV-LED点光源光催化的处理方法。使用UV-LED点光源探究了在不同催化条件下Ti O2对亚甲基蓝的去除效果。结果发现,在反应时间为4 h、p H为11、催化剂用量为1 g/L、溶液初始质量浓度为5 mg/L时,亚甲基蓝的去除率达到73%。UV-LED点光源催化降解亚甲基蓝的反应速率常数k符合准一级反应动力学公式,计算出k=0.064 6e-0.02ρ00.024 9p H0.335 1(0.012M3-0.06M2+0.077 4M+0.034 3)。     

α-四(3-羧基苯氧基)酞菁钴的合成、表征及光催化降解亚甲基蓝

以3-硝基邻苯二甲腈为原料合成了α-四(3-羧基苯氧基)酞菁钴,利用IR、UV-Vis、LC-MS和C H N元素分析对催化剂进行了表征。在室温条件下,研究了催化剂用量和H2O2浓度对亚甲基蓝降解效果的影响。当催化剂用量为0.6 g/L、H2O2浓度为6mmol/L时,80 min后亚甲基蓝的脱色率均可达98.7%。脱色过程符合一级动力学特征,速率常数k=0.039 min-1。重复试验3次,脱色效果可达85%。     

RGO-ZnFe2O4的制备及光Fenton反应降解罗丹明B

采用高能超声复合法制备RGO-ZnFe₂O₄,在模拟太阳光下评价其催化光Fenton反应性能。通过XRD、TEM、FTIR和漫反射光谱分析催化剂的形貌和理化特性。结果表明,RGO的加入可增强ZnFe₂O₄的光吸收能力。以罗丹明B溶液为模拟染料废水,降解率为评价指标,探究RGO掺杂量、催化剂用量和H2O2浓度对降解效果的影响。结果表明,RGO掺杂量6%、催化剂用量1 g/L、H2O2浓度20 mmol/L时,光Fenton降解罗丹明B效果最好,60 min后的降解率达到88.6%。     

马蹄皮吸附剂的制备及吸附甲基橙的性能研究

为了对二甲胺进行胺化,以马蹄皮为原料,对其进行预处理后,用环氧氯丙烷进行醚化,将制备的马蹄皮吸附剂对甲基橙进行吸附,研究吸附剂用量、p H、甲基橙初始质量浓度、反应温度等因素对马蹄皮吸附剂吸附甲基橙效果的影响,通过单因素和正交试验获得最佳吸附条件。结果表明,最佳的吸附条件为:吸附剂用量6 g/L、p H2、甲基橙质量浓度100 mg/L、反应温度30℃。在此条件下,马蹄皮吸附剂对甲基橙的吸附率达97.19%。     

β_2-(TBA)_6SiW_(11)O_(39)Co的合成及光催化性能研究

制备了β_2-(TBA)_6[SiW_(11)O_(39)Co(H2O)]·x H2O多酸电荷转移配合物,用IR、UV、XRD等方法进行了表征。以β2-(TBA)6[SiW11O39Co(H2O)]·x H2O作为光催化反应的催化剂,分别催化降解龙胆紫和亚甲基蓝染料溶液。实验结果表明:初始质量浓度为15mg/L的龙胆紫溶液,加入80 mg/Lβ2-(TBA)6[SiW11O39Co(H2O)]·x H2O,pH=5时,在太阳光下照射140 min,脱色率达85.16%;初始质量浓度为15 mg/L的亚甲基蓝溶液,加入160 mg/Lβ2-(TBA)6[SiW11O39Co(H2O)]·x H2O,pH=4时,在太阳光下照射140 min,脱色率达72.77%。     

悬浮纳米TiO2自然光助催化降解偶氮染料酸性大红GR

以自然光为光源,悬浮纳米TiO2为光降解催化剂,研究了溶液pH值、酸性大红GR初始质量浓度、TiO2质量浓度、H2O2的质量浓度及光照时间对偶氮染料酸性大红GR降解的影响.结果表明悬浮纳米TiO2自然光光助催化降解酸性大红GR的适宜条件为:溶液pH值6.5,酸性大红GR初始质量浓度40 mg/L,TiO2质量浓度1.2 g/L,H2O2质量浓度5 g/L,光照时间为120 min.在此条件下,酸性大红GR降解率达75%以上,且降解反应符合一级反应动力学,其动力学常数为0.011 min-1.     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.