硝酸介质中DCH_(18)C_6对Sr~(2+)的萃取行为研究

文章研究了硝酸介质中二环己基-18-冠醚-6(DCH18C6)对锶的萃取行为。通过考察稀释剂、相比(O/A)、萃取剂浓度及硝酸浓度对萃取过程中分配比和萃取率的影响,得出了DCH18C6在硝酸介质中对Sr2+的萃取规律。实验结果表明,该萃取体系在硝酸介质中能够有效地萃取锶,在萃取相比为1∶4,DCH18C6的浓度为0.1 mol/L,硝酸浓度为1.0 mol/L时,一次萃取率高于90%,用去离子水反萃四次,反萃率可达100%。     

钛白废酸再利用工艺研究

为解决钛白废酸在浓缩时,硫酸亚铁晶体析出堵塞管道的问题。文章利用双氧水把废酸中Fe2+氧化成Fe3+,通过盐酸络合,再用有机溶剂萃取除去其中大部分的三价铁离子络合物。通过实验:综合考虑盐酸体积用量、不同萃取剂、萃取级数对三价铁离子萃取效果的影响,并初步考察反萃效果对萃取剂回收重复利用的可行性。实验结果表明:在钛白废酸中加入6mol/L的盐酸,废酸与盐酸体积比为1:3.5,采取萃取相比为O/W为1:1时,磷酸三丁酯、异丁醇、苯甲酸乙酯、甲苯等都可以作为萃取剂。其中,异丁醇与苯甲酸乙酯的混合液(体积比1:1)与废酸的萃取相比为2:1时,经过3级萃取,Fe3+的萃取率可达96%。用水做反萃剂,对混合萃取剂进行反萃时考虑到异丁醇会溶于水相中,采用一级反萃后,反萃率可达99%,水相蒸馏再生萃取剂可以重复利用。处理之后的钛白废酸可以直接蒸发浓缩至72%时,无杂质析出。     

硝酸银络合萃取蚕蛹油α-亚麻酸酯

研究了硝酸银络合萃取法分离纯化蚕蛹油中α-亚麻酸酯。考察了萃取温度、萃取剂中甲醇体积分数、硝酸银浓度对α-亚麻酸酯分配比的影响,确定了配位萃取条件和反萃条件。实验结果表明,以40％甲醇水溶液为溶剂,AgNO3浓度为2moL／L,0℃下萃取2h,负载α-亚麻酸酯的萃取剂采用石油醚50℃升温反萃30min,所得产品中α-亚麻酸酯的纯度达到97．9％,收率为44．3％,萃取剂再生方便。     

十二胺萃取分离制革污泥淋滤液中铁和铬的方法研究

采用十二胺盐(RNH2Cl)为萃取剂,萃取分离制革污泥淋滤液中的Cr3+与Fe3+。结果表明,在pH=2左右,采用10%RNH3Cl-10%正辛醇-正己烷萃取体系,Fe3+的萃取率达到99%,有效地分离了制革污泥淋滤液中的Fe和Cr。并且以1mol·L-1的盐酸作为反萃剂反萃负载有机相,单级反萃率可以达到90%左右。针对试验中产生的两相乳化现象,破乳条件为:80℃、NaCl的浓度15g·L-1,两相在10min即可分层。     

反胶束法提取核桃粕中蛋白的前萃工艺研究

研究了AOT/正己烷反胶束体系萃取脱脂核桃蛋白的前萃工艺,第1步正交试验,研究了含水量、KCl浓度和pH值对反胶束前萃取核桃蛋白的影响;第2步正交试验,研究了原料粒度、提取时间和料液比对核桃蛋白前萃率的影响。通过2步正交试验,对反胶束体系提取条件进行了优化,得出最优萃取条件为:含水量为20、KCl浓度0.1 mol/L、pH值8.0的反胶束体系,原料粒度80目、提取时间90 min和料液比1∶30,蛋白提取率68.7%,与传统提取方法即碱提酸沉法相比,提取率较高。     

混合醇萃取剂从浓海水中提硼的工艺研究

文章以某地的浓海水为原料,重点研究了利用混合醇体系萃取硼的工艺参数以及机理.针对不同的醇体系,从原料液酸度、相比、萃取剂浓度以及反萃取剂的选择和萃取级数等方面进行了对比,从而得到了最佳的工艺条件以及流程参数.     

反胶束提取小麦胚芽蛋白的工艺研究

以副产品小麦胚芽为原料,用反胶束法研究了小麦胚芽蛋白的提取条件,包括前萃和后萃。前萃由琥珀酸二(2-乙基己基)酯璜酸钠(AOT)-异辛烷-氯化钾缓冲溶液组成的反胶束体系从小麦胚芽中提取蛋白;后萃先回收异辛烷,少量KCl的缓冲溶液溶解剩余的固形物,最后用丙酮沉淀得小麦胚芽蛋白。通过单因素实验,考查了AOT浓度、萃取时间、加入小麦胚芽粉量、温度、KCl浓度、缓冲溶液pH、W/O对小麦胚芽蛋白前萃率的影响以及KCI浓度、缓冲液pH、缓冲液加入量对小麦胚芽蛋白后萃率的影响。     

中空纤维膜非接触式萃取-反萃分离发酵液中丁酸的研究

以丁酸发酵液为原料,采用聚偏氟乙烯PVDF中空纤维膜对发酵液中高浓度的丁酸进行了萃取-反萃研究。考察了发酵液初始pH、丁酸初始浓度、发酵液流速、有机相流速及反萃剂流速对丁酸分离效果的影响,通过响应曲面法确定了最佳工艺条件。结果表明,发酵液初始pH对丁酸分离效果影响最大,发酵液流速及丁酸初始浓度次之,萃取相及反萃剂流速对分离效果影响不大。在萃取相与反萃剂流速均为90mL/min,发酵液流速为129mL/min,发酵液中丁酸含量为74.5mg/mL,发酵液初始pH为2.2时,丁酸最高回收率为85.22%。     

不同反胶束体系后萃取花生蛋白质的比较

对AOT[二-(2-乙基己基)琥珀酸酯磺酸钠]/异辛烷,SDS(十二烷基硫酸钠)/异辛烷-正辛醇,DTAC(十二烷基三甲基氯化铵)/正庚烷-正己醇3种反胶束体系萃取花生蛋白质的后萃工艺进行研究.主要研究了缓冲溶液pH值、萃取时间、萃取温度、超声功率、KCl浓度对花生蛋白后萃率的影响,分别得到了3种反胶束体系萃取花生蛋白质的最佳后萃工艺条件,并做验证试验.在最优工艺条件下制备不同的花生蛋白样品.通过色差分析,从宏观上比较不同反胶束体系制备的花生蛋白产品色泽的差异,进一步对比不同反胶束体系制备的花生蛋白的扫描电镜(SEM)照片,分析其微观结构的差别,试验结果表明最适合萃取花生蛋白的反胶束体系是AOT反胶束体系,且该体系萃取花生蛋白的后萃率为83.17％,较另外2种体系的后萃率都高.     

有机溶剂萃取分离水中L-色氨酸和L-谷氨酸

以正辛醇为稀释剂、二(2-乙基己基)磷酸为萃取剂,研究了L-色氨酸和L-谷氨酸在有机相中的萃取分配行为.在pH=2.0时,L-色氨酸从水相转入有机相,实现L-谷氨酸与L-色氨酸的分离.使用等体积的1mol/L HCl溶液将负载有机相中的L-色氨酸反萃回水相,L-色氨酸的平均回收率为70.8％.2种氨基酸混合水溶液经有机溶剂2次萃取后,可得L-谷氨酸纯品,其平均回收率为97.6％.     

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.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the