固相萃取-氢化物产生-原子荧光光谱法检测 大米中总砷的含量

目的建立基于UIO66材料分散固相萃取体系的提取大米中总砷,并采用氢化物产生-原子荧光光谱法检测其含量。方法以7 mL 0.06 mol/L HNO_3+3%H_2O_2为消解液,在最大微波功率800 W下, 180℃微波消解20min,提取大米中的总砷,通过金属有机骨架材料UIO66实现大米提取液中总砷的分离净化,最后采用氢化物产生-原子荧光光谱法进行总砷含量测定。结果在10～80μg/kg浓度范围内,总砷的标准曲线方程线性良好(相关性系数r~2=0.9997),最低检出限(limitofdetection,LOD)为0.024μg/kg,样品加标回收率在93.4%～107.8%之间,相对标准偏差2%。7种大米样品中的总砷含量在150～250μg/kg之间,其中糙米中总砷含量最高(244.53±4μg/kg),东北地区产大米与南方地区产大米的总砷含量存在显著性差异(P0.05)。结论基于UIO66分散固相萃取体系的大米中总砷分离分析方法具有高灵敏度、低成本、易操作的特点,可有效实现大米中总砷的净化和定量分析。     

福建主产乌龙茶中无机砷的分析与风险评价

目的评价乌龙茶中的无机砷含量,并对无机砷的暴露风险进行评估。方法收集春、夏、秋3个季节采摘的8个福建省主栽乌龙茶品种,采用微波辅助消解-固相萃取-氢化物产生原子荧光光谱法(microwave assisted digestion-solid phase extraction-hydride generation-atomic fluorescence spectrometry,MAD-SPE-HG-AFS)测定其无机砷含量并进行无机砷暴露风险评估。结果乌龙茶中无机砷的含量在0.037~0.050 mg/kg之间,平均含量为0.043 mg/kg,其中秋季采摘的武夷水仙茶叶中的无机砷含量最高。方差分析结果表明,不同季节采摘的乌龙茶中无机砷含量差异不显著,而同一季节不同乌龙茶品种中无机砷含量存在显著差异。依据美国环境保护署(United States Environmental Protection Agency,USEPA)规定的每日无机砷摄入限量(reference dose,RfD=0.3μg·(kg·bw)~(-1)·d~(-1))评价表明,人体通过乌龙茶无机砷的每日暴露量(estimated daily intake,EDI)为6.80E-07~9.19E-07 mg/(kg·d),乌龙茶中无机砷含量的危害商值(hazard quotient,HQ)值均小于1。结论福建省主栽乌龙茶品种中无机砷含量低,通过摄入乌龙茶导致消费者无机砷暴露的风险极低。     

微波辅助萃取-原子荧光光谱法测定虾酱中的无机砷

建立了一种测定虾酱中无机砷的微波辅助萃取-原子荧光光谱法,虾酱中的无机砷经微波萃取后,采用标准曲线法测定。结果表明:无机砷的线性范围为0~8.0μg/L,相关系数为0.99967,无机砷的加标回收率为95.8%~101.1%,相对标准偏差(n=6)为0.92%,检出限为0.052μg/L。结果显示:该方法灵敏度高、简便快捷,可准确测定虾酱中无机砷的含量。     

程序控温石墨消解/微波灰化-氢化物发生-原子荧光光谱法测定食用海藻中总砷

目的建立采用程序控温石墨消解/微波灰化-氢化物发生-原子荧光光谱法分析测定食用海藻中总砷的方法。方法样品加入5 ml HNO3,190℃程序控温石墨预消解30 min;加入灰化辅助剂硝酸镁,550℃微波灰化5 min,用HCl溶解灰分,采用氢化物发生-原子荧光光谱法(HG-AFS)测定总砷含量。结果方法检出限为0.42μg/L,RSD5.0%,加标回收率为96%~109%。测定程序控温石墨消解/微波灰化后消解液中砷形态,确认食用海藻中99%以上的有机砷均消解为无机砷。本方法测定了海带(GBW08517)和紫菜(GBW10023)标准物质,分析结果均在标准值范围内。结论本方法重现性好、结果准确可靠,适用于食用海藻中总砷的测定。     

应用阴离子交换树脂法进行食品中砷形态的研究

目的建立溶剂提取-阴离子交换树脂分离-氢化物发生原子荧光光谱法测定食品中无机砷、一甲基胂(MMA)和二甲基胂(DMA)的方法。方法以水-甲醇为提取剂,阴离子交换树脂分离,HG-AFS检测。结果方法检出限以砷计分别为:无机砷(As(Ⅲ) As(Ⅴ))0·34μg/L、MMA0·57μg/L、DMA0·46μg/L;20μg/L砷标准偏差为:无机砷2·45%、MMA3·34%、DMA4·96%。在0~50μg/L砷量范围校正曲线线性关系良好。试样加标回收率为:无机砷95·40%~97·00%,MMA97·80%~104·80%,DMA104·23%~107·50%。结论对海带、紫菜等海产品及大米等食品的检测,证明该方法简便易行。     

在线紫外消解-原子荧光光谱法测定黄酒中的砷

采用在线紫外消解-氢化物发生原子荧光光谱法测定黄酒中的砷。将自制的紫外消解与氢化物发生原子荧光光谱仪建立系统,考察了紫外消解功率、紫外消解管路长度、辅助消解剂浓度、溶液p H等因素对紫外消解效率的影响。在优化的实验条件下,砷的线性范围为0～40μg/L,相关系数r为0.9989,检出限为1.86μg/L,相对标准偏差为(n=12)3.57%,加标回收率为93.4%～104.6%,本法与国标法测定黄酒中砷的结果基本相同。可用本法代替国标法(GB5009.11-2014)中的氢化物发生原子荧光光谱法测定黄酒中的砷,既可提高工效十余倍,又减少了化学试剂对环境所造成的污染。     

聚乙烯亚胺修饰氧化石墨烯材料选择性吸附分离乌龙茶叶中无机砷的研究

摘要：目的 将聚乙烯亚胺(polyethyleneimine,PEI)修饰于氧化石墨烯(graphene oxide,GO)表面,制备PEI@GO合成材料以实现乌龙茶叶中无机砷的选择性吸附分离。方法 利用傅里叶红外光谱、电镜扫描、Zeta电位分析对PEI@GO进行表征,并建立基于PEI@GO的管尖固相萃取(pipette tip solid phase extraction,PTSPE)体系结合氢化物发生-原子荧光光谱法(hydride generation atomic fluorescence spectrometry,HG-AFS)实现乌龙茶中无机砷的选择性吸附分离和准确定量。结果 傅里叶红外光谱图中出现N-H特征峰,表明PEI成功修饰于GO的表面,电镜下PEI@GO呈现多孔的山脊山谷结构,Zeta电位分析其等电点约为9.7,在pH 6下,5 mg PEI@GO对As (V)溶液吸附率达95.84%,所建立的PTSPE-HG-AFS法最低检测限为0.027 μg/L,相对标准偏差为0.48%,不同品种乌龙茶样品中无机砷含量为13~122 μg/kg,回收率在86.48%~108.98%之间。结论 制备的PEI@GO材料可有效实现无机砷的选择性吸附分离,所建立的方法操作简便,灵敏度高,可准确用于实际茶叶样品中无机砷的分析检测。     

微波消解-原子荧光法测定婴儿食品中的砷

目的：建立微波消解-原子荧光法测定婴儿食品中砷的方法。方法：婴儿食品采用微波消解,双道氢化物发生原子荧光法测定样品中的砷。结果：砷的质量浓度在0μg/L～160.0μg/L范围内与原子荧光强度呈良好的线性关系,相关系数为0.999 2,方法检出限为0.038 2μg/L,回收率为93.47%~98.51%。结论：方法简...     

氢化物发生原子荧光光谱法同时测定进出口蜂皇浆中有害元素砷、汞

建立微波消解-氢化物发生原子荧光光谱法(HG-AFS)时测定进出口蜂皇浆中砷、汞残留的方法,并对HC-AFS工作参数及条件进行了优化和选择.As检出限为0.07μg/L,Hg检出限为0.008μg/L,回收率范围为94%～101%.操作简便、快速、灵敏度高,应用于进出口蜂皇浆中砷、汞残留的检测取得满意的结果.     

微波消解-氢化物发生双道原子荧光光谱法同时测定糖蜜中的砷和汞

建立了微波消解-氢化物发生双道原子荧光光谱法同时测定糖蜜样品中砷和汞的分析方法。实验探索了酸的种类比例、固液比、微波强度、消解时间等各种微波消解条件,并对工作条件进行了优化。仪表检出限为砷0.0704μg/L,汞0.0089μg/L;精密度为砷1.13%,汞0.49%;样品加标回收率为砷96.1%～107.6%,汞102.3%～105.1%。应用该方法对广西某制糖集团下属公司的糖蜜中砷和汞的含量进行了分析,结果令人满意。     

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.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.