HPLC和分光光度法测定葡萄酒中丙酮酸

采用高效液相色谱法和可见分光光度法测定葡萄酒中的丙酮酸含量。并比较两种方法的可行性,为葡萄酒中丙酮酸含量的测定提供理论依据。对样品分别进行高效液相色谱法和可见分光光度法测定。对其溶液进行波长的测定,标准曲线的制备,加样回收率的测定,葡萄酒发酵周期丙酮酸测定。结果表明,高效液相色谱法:丙酮酸在0.05~0.8 mg/m L质量浓度范围内有良好的线性关系(r=1),最低检出限为0.126 mg/L,葡萄酒发酵液中平均回收率101.73%(RSD=1.18%);可见分光光度法:丙酮酸在0.1~0.6 mg/m L范围内与吸收度呈线性关系(r=0.992),最低检出限为1.0 mg/L,葡萄酒发酵液中平均回收率为102.04%(RSD=1.91%)。两种方法均可用于丙酮酸的含量测定且方法准确简捷,结果可靠。     

乳制品中非法保鲜剂硫氰酸钠检测方法的研究

对乳品进行前处理后,再分别采用紫外分光光度法、液相色谱法以及离子色谱法对乳品进行硫氰酸钠分析检测,比较各个方法的检测限以及精密度。紫外分光光度法的回收率为99.05%～107.5%,RSD为3.7%,检测限为0.3 mg/L;液相色谱法的回收率为83%～99.06%,RSD为1.31%,检测限为0.2 mg/L;离子色谱法的回收率为81.7%～99.13%,RSD为0.615%,检测限为0.05 mg/L。实验表明,三个分析方法结果可靠,均有各自的适用性,而紫外分光光度法不适合液奶的检测,其他方法对于检测液奶以及奶粉都很适用,这为乳品中非法添加剂的检测评定提供了参考。     

高效液相色谱法快速分析口香糖中戊二醛的残留量

建立了用高效液相色谱法检测口香糖中灭菌剂戊二醛残留量的方法.样品萃取液与2,4-二硝基苯肼反应后用高效液相色谱测定,外标法定量.该方法快速、准确,在0.2～5.0 mg/L范围内线性相关系数为r2=0.9995,平均回收率达到77.2%～83.9%,相对标准偏差为4.95%～6.22%,最低检测浓度为0.2 mg/L.     

固相萃取高效液相色谱法测定猪肉中六种苯并咪唑类药物残留的研究

建立了高效液相色谱法(HPLC)测定猪肉中硫氧苯唑、噻苯咪唑、 康苯咪唑、甲苯咪唑、丙硫咪唑和硫苯咪唑残留量的检测方法。样品用乙酸乙酯提取,HLB 固相萃取小柱净化,采用高效液相色谱分离,二极管阵列检测器(PDA)检测,外标法定量。结果表明：标准校准曲线在20～1000ng/ml 的范围内呈良好线性关系,相关系数r ＞ 0.99。样品中硫氧苯唑、噻苯咪唑、 康苯咪唑、甲苯咪唑、丙硫咪唑和硫苯咪唑的添加水平分别为0.05、0.1、0.15mg/L 时,样品加标回收率为68.5%～83.7%,变异系数在1.6～7.3 之间。本法简便、快速、定量准确、精密度高,适用于猪肉中苯并咪唑类药物残留量的检测。     

纺织品中五氯酚残留量检测方法的研究

概述了纺织品五氯酚(PCP)残留量的检测方法,包括分光光度法、高效液相色谱法(HPLC)、高效液相色谱/质谱联用法(HPLC/MS)、气相色谱法(GC)、气相色谱/质谱联用法(GC/MS)和免疫分析法等,总结了各种检测方法的优缺点,并提出了纺织用PCP残留检测的发展方向.     

分光光度法检测葡萄酒中花青素方法可行性分析

目的 分析分光光度法检测葡萄酒中花青素方法的可行性,并对方法进行优化。方法 通过分析标准品和样品的全波长扫描图,确定分光光度法的最佳检测波长;通过检测不同储存时间时标准品吸光值,分析标准品稳定性,确定标准品储备液最佳使用时间;通过检测加标回收率、检出限、定量限等参数,同时做与液相色谱法的数据对比,分析该方法的稳定性和准确性。 结果 最佳检测波长为518 nm;标准品母液在2 d内吸光值比较稳定;线性范围为1~20 μg/mL时,r2为0.9998,检出限为0.188 mg/100 mL,定量限为0.625 mg/100 mL。加标水平为4、8、12 mg/100 mL时,加标回收率为102.3%~106.5%。分光光度法检测葡萄酒样品中花青素含量为(6.58±0.38) mg/100 mL,液相法检测样品中总花青素含量为(6.84±0.021) mg/100 mL。结论 分光光度法适合用于葡萄酒中花青素含量的检测,方法准确性较好。     

固相萃取-高效液相色谱法测定猪肉与鸡肉中替米考星、泰乐菌素残留量

建立了高效液相色谱法(HPLC)测定猪肉与鸡肉中替米考星、泰乐菌素残留量的检测方法.样品用乙腈提取,C18固相萃取小柱净化,采用高效液相色谱分离,二极管阵列检测器(PDA)检测,外标法定量.结果表明:标准校准曲线在30～1000μg/L的范围内呈良好线性关系,相关系数r＞0.999.样品中替米考星、泰乐菌素的添加水平分别为0.05、0.10、0.15mg/kg时,样品加标回收率为72.7％～90.8％,变异系数在2.6％～8.3％之间,替米考星和泰乐菌素方法检出限30μg/kg,定量限为50μg/kg.本法简便、快速、定量准确、精密度高,适用于猪肉和鸡肉中替米考星与泰乐菌素残留量的检测.     

高效液相色谱测定啤酒中的黄腐酚

通过C18固相微萃取柱的富集,利用高效液相色谱法实现了啤酒中μg/L级的黄腐酚检测.选取市场啤酒样品进行定量分析,获得了同国外文献较为一致的结果,其检测线性范围为0.011～5.0mg/L,线性系数为0.9997,连续进样RSD为2.3%,加标回收率为94%～98%.     

多功能针式过滤器-高效液相色谱法快速检测豆芽中的吲哚乙酸

基于Qu ECh ERS原理,该研究建立了多功能针式过滤器-高效液相色谱法快速检测豆芽中的吲哚乙酸。样品经1%乙酸乙腈和1 g氯化钠、2 g硫酸镁提取,多功能针式过滤器快速净化后,采用ZORBAX SB-C₁₈(4.6×250 mm,5μm)为色谱柱,以乙腈和0.1%甲酸溶液为流动相,梯度洗脱,流速1.0 mL/min,柱温:35℃,检测波长:267 nm,对提取净化液中吲哚乙酸含量进行高效液相色谱检测。吲哚乙酸在豆芽基质中基质效应较小,故使用纯溶剂配制的标准曲线进行定量。结果显示,吲哚乙酸在0.05~10.0 mg/L范围内线性关系良好,相关系数为0.9999。在0.1~5.0mg/kg的加标水平范围内得到的平均回收率为80.6%~105.3%,相对标准偏差(RSD)是2.3%~4.6%。检出限为0.03μg/kg,定量下限为0.1μg/kg。该方法操作简单、准确可靠,适用于豆芽中吲哚乙酸残留量的快速检测。     

非洲山毛豆种子中鱼藤酮类化合物的含量测定

分别采用高效液相法和紫外分光光度法测定山毛豆种子中鱼藤酮及其类似物的含量.两种试验方法均以鱼藤酮为对照品.用紫外分光光度法在其最大吸收波长294 nm处进行测定.高效液相色谱法以zorbax eclipse plus C18 (4.6 mm×250 mm,5 μm)为色谱柱,流动相为V(甲醇)∶V(水)=69∶31,柱温25℃,流速0.8 mL/min,进样量10μL,检测波长294 nm.试验结果表明,紫外分光光度法测定鱼藤酮类物质含量为24.29 mg/g,高效液相色谱法测定鱼藤酮含量为1.49 mg/g.方法学考察显示,UV法具有方法简便、快速、准确、经济等特点,是一种检测非洲山毛豆种子鱼藤酮类物质含量的较好手段.HPLC法操作相对复杂,但专属性强,重现性好,回收率高,是一种测定鱼藤酮有效含量的方法.     

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.