茶叶中农药残留的检测

为了更好地解决茶叶中的农药残留问题,利用气相色谱仪(具电子捕获检测器)对茶叶中的α-HCH、β-HCH、γ-HCH、δ-HCH、ρ,ρ'-DDE、o,ρ'-DDT、ρ,ρ'-DDD和ρ,ρ'-DDT等农药的残留进行了测定,同时介绍了样品的处理方法,给出了测试的要求及部分样品测试的色谱图。结果表明:部分茶叶中有农药残留,总含量在100μg/L左右。     

气相色谱法检测韭菜中有机氯农药的残留量

采用石油醚提取,浓硫酸磺化的前处理方法和配有电子捕获检测器的气相色谱仪,建立了测定韭菜中有机氯农药α-六六六(α-BHC),β-六六六(β-BHC),γ-六六六(γ-BHC),δ-六六六(δ-BHC),Op'-滴滴滴(Op'-DDD),pp'-滴滴滴(pp'-DDD),Op'-滴滴涕(Op'-DDT),pp'-滴滴涕(pp'-DDT)的前处理和气相色谱检测方法.两种农药在30 min内可得到很好分离,方法回收率为93.54%～98.85%,最低检测限为0.50 ug·kg-1～1.2 ug·kg-1.     

分散固相萃取-气相色谱法测定大米中六六六 和滴滴涕残留量

目的 建立气相色谱-电子捕获检测器法(GC-ECD)测定大米中六六六和滴滴涕(α-六六六、β-六六六、γ-六六六、δ-六六六、o, p’-滴滴滴、o, p’-滴滴伊、o, p’-滴滴涕、p, p’-滴滴滴、p, p’-滴滴伊、p, p’-滴滴涕)残留量的方法。方法 大米样品经乙腈超声提取后,应用PSA进行分散固相萃取净化,高速离心后氮吹浓缩定容,最后使用气相色谱电子捕获检测器测定。结果 六六六和滴滴涕在0.002~0.1 mg/L浓度范围内呈现良好线性关系,R2大于0.99;在0.002、0.005、0.01 mg/kg三个添加浓度上回收率范围为84.10%~111.43%,相对标准偏差小于9.23%,检出限在0.0001~0.0007 mg/kg。结论 该方法前处理操作快速简单,重复性好且灵敏度高,满足国内外对大米中六六六和滴滴涕快速、准确检测的要求,可应用于大量样品的定性定量分析。     

分散固相萃取-气相色谱法测定大米中六六六和滴滴涕残留量

目的建立气相色谱-电子捕获检测器法(GC-ECD)测定大米中六六六和滴滴涕(α-六六六、β-六六六、γ-六六六、δ-六六六、o,p’-滴滴滴、o,p’-滴滴伊、o,p’-滴滴涕、p,p’-滴滴滴、p,p’-滴滴伊、p,p’-滴滴涕)残留量的方法。方法大米样品经乙腈超声提取后,应用PSA进行分散固相萃取净化,高速离心后氮吹浓缩定容,最后使用气相色谱电子捕获检测器测定。结果六六六和滴滴涕在0.002~0.1 mg/L浓度范围内呈现良好线性关系,R2大于0.99;在0.002、0.005、0.01 mg/kg三个添加浓度上回收率范围为84.10%~111.43%,相对标准偏差小于9.23%,检出限在0.0001~0.0007 mg/kg之间。结论该方法前处理操作快速简单,重复性好且灵敏度高,满足国内外对大米中六六六和滴滴涕快速、准确检测的要求,可应用于大量样品的定性定量分析。     

正相高效液相色谱法测定植物油中维生素E的含量

试验建立了正相高效液相色谱法测定植物油中4种维生素E含量的方法。植物油的最佳取样量为0.20 g,在设定的条件下4种维生素E实现了良好的分离,待测维生素E在0.20～6.00μg/m L质量浓度范围内呈良好的线性关系(R~20.999), 4种维生素E的定量限分别为0.15, 0.15, 0.12和0.15 mg/100 g,加标回收率在95.2%～102.3%之间。对市售(流通领域)植物油中维生素E含量进行了测定,发现植物油中各生育酚的含量为γ-生育酚δ-生育酚α-生育酚β-生育酚;γ-生育酚含量范围在39.2～285 mg/100 g之间,δ-生育酚含量范围在1.1～70 mg/100 g之间,α-生育酚含量范围在3～51 mg/100 g之间,β-生育酚含量范围在0.2～6.7 mg/100 g之间。同时测定了餐饮领域的植物油中维生素E含量,发现煎炸用油的α-生育酚、β-生育酚、γ-生育酚和δ-生育酚含量均普遍较低。     

生活用水中六六六和滴滴涕的残留分析

目的利用气相色谱法测定自来水、桶装水、纯水、蒸馏水中的六六六和滴滴涕含量,研究六六六和滴滴涕对不同生活用水污染情况。方法采用液液萃取方法,用石油醚提取水中六六六和滴滴涕,氮吹仪浓缩后用气相色谱仪ECD检测器检测,外标法定量。结果不同生活用水中六六六和滴滴涕均有检出,其中β-BHC、o,p′-DDT检出率为100%,α-BHC检出率为75%,纯水中和桶装水中含量较低。结论六六六、滴滴涕由于其化学性质稳定及高残留性所引起的远期危害不容忽视。     

通州区茶叶中有机氯农药残留及铅污染状况分析

目的:了解通州区部分茶叶中六六六、滴滴涕有机氯农药残留和重金属铅的化学污染状况.方法:采用气相色谱法测定茶叶中六六六和滴滴涕农药残留,用原子吸收分光光度法测定重金属铅的含量.结果:茶叶中六六六检出率为92.1%(35/38),合格率97.1%(34/35),超标率为2.9%(1/35),测定值范围在<0.4-385.0μg/kg之间.滴滴涕检出率为89.4%(34/38),合格率100%,测定值范围为1.4-189.0 μg/kg,以p,p'-DDT的检出最多.重金属化学污染物铅检出率97.6%(37/38),各类茶叶中铅测定结果均低于标准限值.结论 有机氯农药虽然禁用多年,但茶叶中六六六仍有较高残留,提示通州区茶叶中六六六和滴滴涕的农药残留状况不容乐观;重金属铅的检出率较高,食品卫生监督机构应加强监测,保证食品的安全和消费者的健康.     

GC-MS法测定罗汉果中有机氯农药残留量

建立气质联用(GC-MS)法检测罗汉果中甲体-六六六、乙体-六六六、丙体-六六六、丁体-六六六、对对位滴滴依、对对位滴滴滴、邻对位滴滴涕和对对位滴滴涕8种有机氯农药残留量。样品经有机溶剂超声提取,硫酸净化,选用HP-5MS毛细管柱对8种有机氯农药进行分离,外标法计算含量。结果表明:8种有机氯农药的线性范围为5~500μg/L,相关系数均大于0.999 0,方法最低检出限为1.15~2.64μg/kg,在3个浓度水平进行加标(100,150和250μg/L),加标回收率为87.3%~109.8%,相对标准偏差(RSD,n=6)为0.30%~11.76%。该方法操作简单、结果准确、灵敏度高,可用于罗汉果中8种有机氯农药残留的测定。     

高效液相色谱法测定玉米中生育酚异构体

建立了一种玉米中生育酚异构体的测定方法。试验采用Sunfire C18反相柱（5μm4,.6×150 mm）,柱温25℃,甲醇＋水（98＋2）作为流动相,流速1.0 mL/min,进样量20μL,通过荧光检测器（激发波长为295 nm,发射波长为330 nm）测定生育酚异构体。方法线形范围为1～100μg/mL,α-生育酚（、β＋γ）-生育酚、δ-生育酚在此范围内线形良好,相关系数为0.99976～0.99983。在5～50 mg/kg浓度范围内,加标回收率为86.5%～97.4%,相对标准偏差为0.4%～3.5%。α-生育酚（、β＋γ）-生育酚、δ-生育酚的检出限分别为0.03、0.02、0.02 mg/kg。方法快速、灵敏、准确、简便易行。     

QuEChERS-气相色谱-三重四级杆串联质谱法测定 茶叶中的12种有机氯农药残留

目的建立QuEChERS前处理结合气相色谱-三重四级杆串联质谱法(gas chromatography-triple quadrupole tandem mass spectrometry,GC-QqQ-MS/MS)用于茶叶中12种有机氯农药(α-六六六、β-六六六、γ-六六六、δ-六六六、五氯硝基苯、艾氏剂、狄氏剂、七氯、硫丹-I、硫丹-II、顺式-氯丹、反式-氯丹)残留的同时检测分析方法。方法样品经乙腈提取,醋酸钠、无水硫酸镁盐析,QuEChERS方法净化,浓缩后,经气相色谱-三重四级杆串联质谱仪采用多反应离子监测(multiple reaction monitoring,MRM)模式进行分析测定,外标法定量。结果 12种有机氯农药在0.005~0.1μg/mL范围内线性关系良好,线性相关系数(r~2)不小于0.9990;在0.01、0.04和0.1μg/mL 3个添加水平下,平均加标回收率为69.30%~97.02%;相对标准偏差(relative standard deviations,RSDs)为0.56%~9.27%(n=6)。12种有机氯农药的检出限均小于1μg/kg。结论该法样品处理快速简单,灵敏度高,适用于茶叶中有机氯农残检测工作。     

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.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of     

The Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.