固相萃取-超高效液相色谱串联质谱法检测甘蔗中3-硝基丙酸的方法研究

目的建立甘蔗中3-硝基丙酸的固相萃取-超高效液相色谱串联质谱检测方法。方法样品经乙腈萃取,Sep-pak氨基固相萃取柱净化,超高效液相色谱串联质谱法测定甘蔗中3-硝基丙酸含量。色谱柱为WatersACQUITY BEH C18柱(1.7μm,50 mm×2.1 mm),柱温40℃,样品温度10℃,进样体积5μl,流动相A为水,流动相B为乙腈,梯度洗脱。结果方法的线性范围为4.0～40.0μg/kg,基质加标工作曲线线性相关系数为0.998。方法的定性检出限为1.0μg/kg,定量检出限为4.0μg/kg。高、中、低3个浓度水平的加标回收率为92.5%～93.6%,相对标准偏差小于10%。结论本方法灵敏、快速、准确,可用于甘蔗中3-硝基丙酸的测定。     

高效液相色谱-串联质谱法测定甘蔗中的3-硝基丙酸含量

目的建立高效液相色谱-串联质谱法(high liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)检测甘蔗中的3-硝基丙酸含量。方法样品经乙腈提取,经Sep-pak氨基柱固相萃取净化,再经Merck seQuant~(TM) Zic-Hilic(150 mm×2.1 mm,5μm)色谱柱分离,以10 mmol/L甲酸铵-0.1%甲酸和乙腈为流动相进行梯度洗脱,采用电喷雾负离子(electrospray ionization,ESI-)模式进行HPLC-MS/MS测定。结果 3-硝基丙酸在0.005~0.1 mg/L浓度范围内呈良好的线性关系,工作曲线的回归方程为Y=4.48X+46.72,相关系数为0.9994,该方法的检出限为0.0036 mg/kg,定量限为0.0119 mg/kg。在0.02、0.08和0.1 mg/kg加标水平下,3-硝基丙酸的平均回收率为80.0%~96.8%,相对标准偏差为1.90%~8.69%(n=6)。结论本方法快捷、灵敏度高、结果准确,可适用于甘蔗中的3-硝基丙酸的检测。     

高效液相色谱串联质谱法测定红糖中3-硝基丙酸

建立了红糖中3-硝基丙酸的高效液相色谱串联质谱检测方法。红糖样品用乙醇-水溶解,涡旋振荡,离心后取上清液,用PWAX固相萃取柱净化,氮气吹干洗脱液,甲醇-甲酸水复溶后,用高效液相色谱串联质谱检测。采用Luma Omega C_(18)柱(1.6μm,100 mm×2.1 mm),以甲醇和水为流动相进行分离,电喷雾负离子模式(ESI-),多反应监测(MRM)检测,外标法定量。结果表明,3-硝基丙酸在0.1～20μg/L浓度范围内线性关系良好(r=1.0000),该方法的检出限为0.057μg/kg,定量限为0.189μg/kg。在2.5、10、50μg/kg的加标水平下,3-硝基丙酸的平均回收率为79.2%～85.5%,相对标准偏差为5.2%～7.3%以下(n=6)。本方法操作简单、灵敏度高、结果准确,可用于红糖中3-硝基丙酸的残留量测定。     

离子色谱-三重四极杆质谱联用法测定血浆和尿液中3-硝基丙酸

目的建立离子色谱-三重四极杆质谱联用技术测定血浆和尿液中3-硝基丙酸的方法。方法血浆和尿液标本经高氯酸水溶液提取3-硝基丙酸,pH=1～2条件下经固相支持液液萃取法净化,叔丁基甲醚作为萃取剂,萃取液氮吹浓缩后溶于水。以Ionpac AS 19型阴离子色谱柱(250 mm×2 mm,7.5μm)作为分析柱,氢氧化钾作为淋洗液进行梯度分离,电喷雾负离子多反应监测(MRM)模式检测,基质加标标准曲线外标法定量。结果 3-硝基丙酸的线性范围为0.1～250μg/L,相关系数优于0.999,在0.30、1.00、25.0和200μg/L的浓度水平下进行加标回收试验,血浆和尿液中3-硝基丙酸的平均加标回收率为92.0%～114%,相对标准偏差在2.0%～12%之间(n=6),方法的检出限(信噪比为3)均为0.1μg/L。结论本方法简单、灵敏、准确,可用于血浆和尿液中3-硝基丙酸的检测。     

超高效液相色谱-串联质谱法测定纯牛奶中喹乙醇及其代谢物

目的建立可靠的前处理方法 ,采用超高效液相色谱-串联质谱法检测纯牛奶中喹乙醇及其代谢物3-甲基-喹噁啉-2-羧酸(MQCA)。方法样品经盐酸水解,乙腈-乙酸乙酯(1∶1,V/V)提取,分析了直接浓缩及分别经PAX、PEP固相萃取小柱净化、富集的结果 ;以乙腈-0.05%氨水为流动相,经Inertsil ODS-3色谱柱(2.1 mm×100 mm,3μm)分离,采用多反应监测正离子模式进行定性及定量分析。结果直接浓缩具有较好的回收率,喹乙醇的方法检出限为0.06μg/kg,方法定量限为0.20μg/kg,在0.20、1.00、5.00μg/kg 3个加标水平下回收率分别为69.8%、111%、97.4%;MQCA的方法检出限为0.02μg/kg,方法定量限为0.10μg/kg,在0.10、1.00、3.00μg/kg 3个加标水平下回收率分别为75.8%、112%、117%。结论该检测方法适用于纯牛奶中喹乙醇及其代谢物残留的检测。     

分散固相萃取净化-液相色谱-质谱联用测定水产苗种中硝基呋喃类代谢物残留量

建立分散固相萃取净化-液相色谱-质谱法测定水产苗种中氨基脲、5-甲基吗啉-3-氨基-2-噁唑烷基酮、3-氨基-2-噁唑烷基酮、1-氨基-2-内酰脲,4 种硝基呋喃类代谢物残留量的方法。样品经甲醇-水（8∶1,V/V）溶液洗涤后,盐酸溶液水解,以2-硝基苯甲醛作为衍生化试剂,乙酸乙酯萃取,浓缩,分散固相萃取净化,采用液相色谱-质谱仪、多反应监测扫描模式检测和同位素内标定量。4 种硝基呋喃类代谢物在0.5～20 μg/L范围内线性相关系数大于0.997,检出限0.1 μg/kg,回收率90.5%～104.5%,相对标准偏差1.56%～8.08%。本方法灵敏、高效、简单、重复性好,满足硝基呋喃类代谢物的检测要求。     

基质固相分散萃取-超高效液相色谱串联质谱法检测大米中27种农药残留量

目的建立基质固相分散萃取-超高效液相色谱-串联质谱法(matrixsolidphasedispersive extraction-ultra performance liquid chromatography-tandem mass spectrometry, MSPD-UPLC-MS/MS)检测大米中27种农药残留的分析方法。方法以中性氧化铝为吸附剂, C18为固相萃取净化剂,以甲醇-二氯甲烷(2:1, V:V)为洗脱溶剂,提取液经UPLC-MS/MS分析。结果 27种化合物线性关系良好,相关系数均大于0.999,方法检出限为0.2～4.0μg/kg,定量限为0.4～10.0μg/kg;加标回收率为76.7%～113.3%,相对标准偏差为1.7%～13.7%。结论该方法灵敏、准确,适合于大米样品中27种农药残留的定性和定量检测。     

固相萃取-超高效液相色谱-电喷雾串联质谱法测定食用油脂中3-氯丙醇酯

目的建立固相萃取-超高效液相色谱-串联质谱联用法(SPE-UPLC-MS/MS)同时测定食品中18种3-氯丙醇酯的方法,并对部分市售含油脂食品中氯丙醇酯的含量进行调查。方法样品用叔丁基甲醚-乙酸乙酯(8∶2,V/V)超声提取;经Sep-Pak Silica硅胶萃取小柱、OASIS HLB固相萃取小柱(预先用甲醇活化)二次净化,以Acquity UPLC BEH C_(18)色谱柱(2.1 mm×150 mm,1.7μm)分离,以多反应监测模式(MRM)进行监测,内标法定量。结果18种氯丙醇酯在1.0~200.0μg/L范围内线性关系良好(r为0.999 1~0.999 8)。食用油在0.10、1.0和10.0 mg/kg3个添加水平范围内的平均回收率为80.2%~98.5%,RSD8.1%。食用油中18种氯丙醇酯的检出限在1.17~30.1μg/kg之间,92.0%(46/50)的食用油中检出多种3-氯丙醇酯,含量分别在7.55~5 360μg/kg之间;75.0%(9/12)的含油脂食品中检出多种3-氯丙醇酯,含量在6.62~1 569.8μg/kg之间。结论建立的固相萃取-超高效液相色谱-电喷雾串联质谱联用法同时测定食品中18种3-氯丙醇酯的方法快速简单、准确有效,可以满足各种食用油和含油脂食品中3-氯丙醇酯的检测要求。     

超高效液相色谱串联质谱法测定甘蔗中3-硝基丙酸的不确定度评定

分析利用超高效液相色谱串联质谱法(UPLC-MS/MS)测定甘蔗中3-硝基丙酸的不确定度来源,对不确定度的各个分量进行评估和合成。结果表明,影响3-硝基丙酸含量测定的不确定度的主要原因是标准工作曲线配制和重复性测定引入的不确定度分量。当甘蔗中3-硝基丙酸的测定值为152.20μg/kg时,计算得到扩展不确定度为11.62μg/kg,测定结果表示为(152.20±11.62)μg/kg,k=2。     

固相萃取-气相色谱法测定坚果中3种拟除虫菊酯残留量

采用固相萃取-气相色谱法测定坚果中氯氰菊酯、氰戊菊酯、溴氰菊酯残留量等3种拟除虫菊酯。坚果样品采用石油醚提取,固相萃取小柱净化,丙酮-石油醚(1+9)洗脱,用Agilent DB-17色谱柱分离,电子捕获检测器检测。试验结果表明,3种拟除虫菊酯农药的色谱图分离效果良好,在0.05μg/mL～0.8μg/mL范围内,检出限为0.001 5 mg/kg～0.002 4 mg/kg,回收率在94.2%～107.0%之间,相对标准偏差(n=6)为0.93%～3.88%。     

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.