高效液相色谱法检测酸奶中的唾液酸

建立了高效液相色谱-荧光检测器(HPLC-FLD)测定酸奶中唾液酸含量的分析方法。该方法为:使用1moL/L甲酸80℃下水解样品2h,以4,5-亚甲二氧基-1,2-邻苯二铵盐(DMB)为衍生化试剂,在80℃下衍生50min后,利用Zorbax SB-Aq色谱柱对衍生化产物进行分离,荧光检测器检测,外标法定量。该方法唾液酸检出限为0.2mg/L,线性范围0.5~10mg/L之间,线性良好,相关系数为0.9998,加标样品的回收率为88.41%~112.08%之间,相对标准偏差(n=6)为4.73%~10.01%之间。说明该方法检测结果准确,满足检测需求,可用于不同奶制品中唾液酸检测。     

高效液相色谱法测定母乳中唾液酸含量

建立荧光高效液相色谱(fluorescence detector-high performance liquid chromatography,HPLC-FLD)测定母乳中唾液酸N-乙酰神经氨酸(N-acetylneuraminic acid,Neu5Ac)和N-羟乙酰神经氨酸(N-glycolyl neuraminic acid,Neu5Gc)含量的分析方法。利用酸水解法释放出母乳中的唾液酸,以4,5-亚甲二氧基-1,2-邻苯二胺盐(4,5-methylenedioxy-1,2-phenylenediamine dihydrochloride,DMB)为衍生化试剂,50℃避光衍生150min,采用荧光高效液相色谱仪检测。色谱条件:LiChrosorb RP-18柱(250mm×4mm,5μm),流动相为甲醇-乙腈-超纯水(7:8:85),流速0.9mL/min,进样体积10μL,柱温30℃,荧光检测器激发波长373nm,发射波长448nm。结果表明:唾液酸在50～400μmol/L范围内与唾液酸峰面积的线性关系良好,平均回收率为94.0%,精密度的相对标准偏差(relative standard devia...     

奶粉中N-乙酰神经氨酸的检测

建立一种高效液相色谱荧光测定奶粉中N-乙酰神经氨酸(N-acetylneuraminic acid,Neu5Ac)含量的分析方法。该方法利用酸水解释放出奶粉中的Neu5Ac,用邻苯二胺盐(OPD)作为衍生化试剂,80℃避光衍生100 min,采用高效液相色谱荧光检测。色谱条件为:用Thermo Hypersil GOLD柱(250mm×4.6mm, 5μm)分离;流动相选择超纯水-乙腈作为梯度洗脱,柱温为30℃,流速为1.0mL/min;进样体积为10μL;荧光检测器激发波长为337 nm,发射波长为448 nm。结果表明:N-乙酰神经氨酸在0.5～200μg/g范围内线性关系良好(R~2=0.9994),回收率为98%～119%,检出限为0.5μg/g。该方法具有灵敏度高,重复性好等特点,可准确测定市售奶粉中N-乙酰神经氨酸的含量。     

改良柱前荧光胺衍生化-高效液相色谱法测定猪肉中11种磺胺类药物残留

建立改良的磺胺类药物与荧光胺反应的衍生化方法,并应用于猪肉中11种磺胺类药物的高效液相色谱-荧光法测定.选用0.1 mol/L KH2PO4溶液(pH 3.0)0.8 mL、0.3 mg/mL荧光胺溶液0.2 mL与磺胺类药物发生衍生化反应,4℃避光反应40 min,得到磺胺-荧光胺衍生产物.该衍生化方法稳定、可靠,衍...     

高效液相色谱法定量测定果蔬中甲醛含量

通过五氟苯肼与甲醛进行衍生,建立高效液相色谱法定量测定果蔬中甲醛含量的分析方法。样品在温度为60℃超声波条件下直接提取衍生30 min,离心纯化后高效液相色谱检测,外标法定量。优化的色谱条件为:XDB-C_(18)色谱柱(4.6 mm×250 mm,5μm),流动相:乙腈-水(70∶30,V/V),流速1.0 mL/min,柱温40℃,检测波长258 nm。结果表明,该方法的定量检测限可达到0.114 mg/kg,在0.114~57 mg/L范围内呈良好的线性关系,当甲醛添加量分别为1.14、8.55、17.10 mg/kg时,平均回收率为81.4%~101.8%,相对标准偏差为2.6%~5.0%(n=6)。该方法样品前处理简便、稳定性好、检测限低,适合果蔬中甲醛含量的快速检测。     

基于UPLC-FLD建立白酒中尿素的检测方法

基于超高效液相色谱荧光检测器(UPLC-FLD)建立了一种快速、准确定量白酒中尿素的方法.该法中将白酒样品用9-羟基占吨醇在酸性、避光条件下衍生,采用C18反相色谱柱分离目标物,流动相为乙腈和0.02 mol/L乙酸钠溶液(pH 7.2),后经FLD检测分析,检测器波长为λex=213 nm,λem=308 nm,25...     

邻-(2,3,4,5,6-五氟苄基)羟胺盐酸盐衍生-HPLC法测定果蔬中甲醛含量

通过邻-(2,3,4,5,6-五氟苄基)羟胺盐酸盐与甲醛衍生,建立了测定果蔬中甲醛含量的高效液相色谱法。样品在温度为70℃超声波条件下直接提取衍生30 min,经离心纯化后液相色谱检测,外标法定量。优化的色谱条件为:Eelipse XDB-C_(18)柱(4.6 mm×250 mm,5μm);流动相为乙腈和水(70∶30,v/v),流速1.0 m L/min,柱温40℃,检测波长210 nm。结果表明,该方法的检出限可达到0.114 mg/kg,在0.57~57 mg/kg范围内呈良好的线性关系,平均回收率为82.3%~94.1%,相对标准偏差为4.0%~7.1%(n=6)。该方法样品前处理简便,稳定性好,检测限低,适合果蔬中甲醛的快速定量检测。     

燕窝中唾液酸的DAD/FLD串联HPLC测定方法研究

建立燕窝中唾液酸的柱前衍生二极管阵列/荧光检测器(DAD/FLD)串联的反相高效液相色谱检测方法。用硫酸氢钠溶液水解样品,以邻苯二氨盐酸盐为衍生化试剂,采用C18柱分离,四氢呋喃溶液(含体积分数0.5%磷酸和体积分数0.15%正丁胺)-乙腈为流动相等度洗脱,流速1.0mL/min,二极管阵列检测波长230nm,荧光激发波长(Ex)230nm,发射波长(Em)425nm。结果表明,唾液酸在0.1～750μg/mL范围内线性良好(r>0.9990),20min内完全分离,回收率在85.03%～97.14%之间。检出限0.2μg/mL(DAD),0.005μg/mL(FLD),FLD检出限比DAD低两个数量级且杂峰少,在DAD检出限以上的相同浓度下,DAD比FLD更灵敏。本方法具有灵敏度高,重复性好,分析速度快等特点,可准确测定燕窝等样品中唾液酸含量。     

高效液相色谱法快速测定紫贻贝中的牛磺酸

目的:建立用高效液相色谱(HPLC)快速测定紫贻贝中牛磺酸含量的方法.方法:应用邻苯二甲醛(OPA)为衍生试剂进行柱前衍生,采用甲醇、乙腈和水(10∶10∶80,v/v/v)为流动相,色谱柱为Agilent Zorbax 300SB-C1s(4.6mm×250mm,5μm),荧光检测:Ex为330nm,Em为530nm,柱温30℃,流速0.8mL/min,进样20μL分析检测牛磺酸含量.结果:牛磺酸在4.0～20.0μg/mL浓度范围内有良好线性关系,相关系数R2为0.9998,回收率范围在96.65％～101.20％,RSD=1.57％.结论:该方法的样品前处理与衍生化简便、易操作,牛磺酸出峰时间为6.752min,其含量为3673.631 mg/kg,有良好的精确度和准确度,分析时间短,可快速检测紫贻贝中的牛磺酸.     

RP-HPLC柱后衍生法检测干酪中6种生物胺

目的:建立干酪中6种生物胺的高效液相色谱-柱后衍生检测方法。方法:采用高氯酸提取干酪中生物胺,以邻苯二甲醛(OPA)为柱后衍生试剂,高效液相色谱-柱后衍生-荧光法检测。采用Agilent Eclipse XDBC18色谱柱;流动相A为乙酸钠-辛烷磺酸钠溶液,流动相B为乙酸钠-辛烷磺酸钠和乙腈混合溶液,流速1.0m L/min,梯度与等度相结合洗脱方式;柱温40℃;荧光探测器激发波长330 nm,发射波长465 nm;衍生剂流量0.3 m L/min,衍生池温度45℃。结果 :采用本洗脱程序,40 min内6种生物胺完全分离;衍生剂OPA质量浓度0.4 mg/m L,流速0.3 m L/min时衍生效果最佳;6种生物胺标准曲线具有良好的线性关系(R20.9982),平行样品相对标准偏差(RSD)3.8%,方法稳定性良好,6种生物胺样品平均回收率89.25%~103.09%。结论:本法样品预处理简便,灵敏度高,重复性好,准确性高,适合检测干酪中的生物胺。     

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.