分散液液微萃取-火焰原子吸收光度法测定大米中痕量镉

建立了分散液液微萃取–火焰原子吸收光度法测定大米中痕量镉元素的方法。探讨了p H、分散剂–萃取剂用量、络合剂用量、分散剂–萃取剂比例、振荡时间等因素对萃取率的影响,并对共存离子的干扰进行了试验。结果表明,在最佳条件下该方法的检出限为8.876μg/L,回收率在97.0%~102.0%,线性范围为0.00~1.50μg/m L。利用该法测定大米中痕量镉的含量,结果令人满意。     

分散液液微萃取结合气相色谱-火焰光度检测器法测定芝麻香型白酒中3-甲硫基丙醇

研究了超声波辅助分散液液微萃取联合气相色谱测定芝麻香型白酒中3-甲硫基丙醇。筛选优化样品前处理条件,联合气相色谱-火焰光度检测器(gas chromatography-flame photometric detector,GC-FPD)测定其含量。结果表明:分散液液微萃取参数为萃取剂三氯甲烷65μL、分散剂甲醇100μL、样品体积1 m L、样品p H值为3、酒精度12%vol、Na Cl离子强度15%、低温分离时间1 h、离心时间3.5 min,3-甲硫基丙醇提取率为93.01%。在3-甲硫基丙醇质量浓度为50~2 000μg/L时,线性相关系数为0.999 4,检测限为1.5μg/L,定量限为5μg/L。在3-甲硫基丙醇质量浓度分别为50、100、200、400μg/L四个水平下,回收率为92.11%~101.90%。检测5个白酒样品中3-甲硫基丙醇含量,质量浓度分别为110.41~1 238.67μg/L,其中孔府家酒含量最高。     

大体积进样气相色谱串联质谱法测定饮用水中29种半挥发性有机物

建立了饮用水中29种半挥发性有机物的三重四级杆气质联用仪大体积进样检测方法。水样样品经甲基叔丁基醚液液萃取,采用溶剂放空模式程序升温大体积进样,MRM多反应离子监测,内标法定量。结果表明:在0.2~10.0μg/L质量浓度范围内,各化合物的响应值与浓度呈良好的线性关系(r>0.994),方法检出限为0.003~0.110μg/L,加标回收率在61.7%~108.6%,相对标准偏差(n=6)为1.5%~8.7%。该方法样品前处理简单,灵敏度高,适用于饮用水中29种半挥发性有机物的同时测定。     

分散液液微萃取-高效液相色谱法测定枸杞中α-生育酚

建立基于分散液液微萃取样品前处理法,并结合高效液相色谱紫外检测技术测定枸杞中α-生育酚的含量,考察影响分散液液微萃取的因素包括萃取剂和分散剂类型及用量、p H值、离子强度、萃取时间和萃取温度。方法的线性范围为100~50 000μg/L,r=0.999 7。在最优条件下,日内和日间重复性分别为2.9%和6.5%,检出限为3.1μg/L,定量限为10.2μg/L。并将该法成功应用于3种市售枸杞中α-生育酚含量的测定,加标回收率为85.7%~106.3%,相对标准偏差为0.68%~4.62%。方法具有有机溶剂用量少、操作简单快捷、准确度和灵敏度高、重复性好等优点。     

固相萃取光度法测定饮用水中痕量磷酸盐的研究

基于固相萃取分离技术结合分光光度法,建立了一种测定水中痕量磷酸盐的分析方法。磷钼蓝（PMB）与十六烷基三甲基溴化铵（CTMAB）可生成疏水性的PMB-CTMAB离子缔合物,被Sep-Pak C18固相萃取小柱富集,用丙酮和硫酸混合液洗脱以后用分光光度法测定,固相萃取柱不被破坏且可重新处理使用。同时研究了固相萃取条件,讨论了共存离子的干扰及消除。该方法测定饮用水中痕量磷酸盐含量灵敏度高,选择性好,检测限为0.14μg/L（n=7）,其相对标准偏差RSD为3.1%～6.7%（n=7）,标准加入回收率为95%～102%,其结果令人满意。     

涡旋辅助分散液液微萃取-气相色谱法测定清香型白酒中5种高级醇

采用涡旋辅助分散液液微萃取（DLLME）-气相色谱（GC）法测定清香型白酒中5种高级醇的含量。结果表明,最佳液液微萃取的提取条件为萃取剂二氯甲烷60 μL、分散剂丙酮100 μL、样品pH值5.5、酒精度15%vol、NaCl质量浓度0.19 g/mL、萃取时间30 s。在此优化条件下,正丙醇和异丁醇在含量为1.00～40.00 mg/L、异戊醇在含量为1.00～150.00 mg/L、2,3-丁二醇在含量为1.25～50.00 mg/L和β-苯乙醇在含量为0.25～10.00 mg/L的范围内具有较好的线性关系（R2＞0.99）;检出限分别为0.03 mg/L、0.01 mg/L、0.01 mg/L、0.02 mg/L和0.02 mg/L;精密度试验结果相对标准偏差（RSDs）＜7.0%,回收率为83.1%～108.3%。6种清香型白酒中正丙醇含量范围为0.064～0.116 g/L、异丁醇含量范围为0.057～0.127 g/L、异戊醇含量范围为0.262～0.450 g/L、2,3-丁二醇含量范围为0.017～0.035 g/L、β-苯乙醇含量范围为0.008～0.012 g/L。     

涡旋辅助液液微萃取结合GC-MS法检测67 种白酒中四甲基吡嗪、4-甲基愈创木酚4-乙基愈创木酚

采用涡旋辅助液液微萃取结合气相色谱-质谱（gas chromatography-mass spectrometry,GC-MS）法对67?种白酒中四甲基吡嗪、4-甲基愈创木酚和4-乙基愈创木酚进行检测。酒样经二氯甲烷提取,涡旋辅助萃取1?min,6?000?r/min离心5?min,然后采用GC-MS进行分析。结果表明,四甲基吡嗪、4-甲基愈创木酚和4-乙基愈创木酚分别在质量浓度为0.5～2?500、1.0～2?500、1.0～2?500?μg/L的范围内具有较好的线性关系（R2＞0.99）;检出限分别为0.25、0.5、0.5?μg/L;不同添加水平的平均回收率为80.1%～88.0%。对67?种白酒含量分析表明,所有样本都含有四甲基吡嗪,含量范围为1.5～2?434.3?μg/L;51?种样本中含有4-甲基愈创木酚,含量范围为2.8～1?709.0?μg/L;53?种样本中含有4-乙基愈创木酚,含量范围为1.3～1?167.5?μg/L。白酒酿造原料、工艺的差异可能是造成其健康因子含量不同的潜在因素。     

液液萃取气相色谱法测定饮用水中有机氯农药

采用正己烷液-液萃取法提取,气相色谱法-电子捕获检测器测定饮用水中8种滴滴涕农药。结果表明8种滴滴涕农药的方法检出限为1.63μL~3.33μL回收率为82.1%~106.1%在1μL~100μL内质量浓度与峰面积呈良好的线性关系,相关系数均大于0.999。该方法操作简便、检出限低,准确度和精密度高,适用于饮用水中滴滴涕农药的分析。     

液液萃取-高效液相色谱法测定红茶中赭曲霉毒素A

目的：建立一种液液萃取净化的高效液相色谱法测红茶中的赭曲霉毒素A的方法。方法：试样经60%乙腈超声提取，液液萃取净化，以甲醇～0.5%乙酸梯度洗脱，C18短柱分离后经高效液相色谱仪-荧光检测器检测。结果：赭曲霉毒素A在10.00μg/L～50.00μg/L浓度范围，相关系数为1.00000，加标回收率为83%～98%,RSD为1.11%～2.47%，检出限为0.0052mg/kg。结论：仪器20min完成一个样品测定，方法检测速度快，同时具有净化效果好，精密度和准确度高的特点。     

超声辅助冷诱导分散液-液微萃取用于牛奶中三聚氰胺的检测

将分散液相微萃取、超声萃取技术相结合,采用四氯乙烯作为萃取剂,建立超声辅助冷诱导分散液-液微萃取技术对牛奶中的三聚氰胺进行检测。采用四氯乙烯作为萃取剂,在优化的萃取条件下,三聚氰胺的线性范围为10～200μg/L。应用于牛奶样品中微量三聚氰胺的检测,平均回收率分别为95.9%,相对标准偏差分别为4.47%,建立的方法灵敏度高,准确可靠,适合牛奶中三聚氰胺的检测。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

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

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status