高效液相色谱法测定柑橘中6种防腐保鲜剂的残留

建立了同时对柑橘中6种防腐保鲜剂包括对羟基苯甲酸甲酯（尼泊金甲酯）、对羟基苯甲酸乙酯（尼泊金乙酯）、乙萘酚、4-苯基苯酚、2,4-二氯苯氧乙酸（2,4-D）和联苯醚（二苯醚）残留量进行测定的高效液相色谱法。样品经乙醚提取后,活性炭柱净化。C18 色谱柱分离,流动相为甲醇:水（55:45,磷酸调节pH≈3）,二极管阵列检测器,检测波长为208 nm。结果表明：6种标准物质在1.2~4.0 μg/mL范围内呈良好线性关系,相关系数均可达到0.999,在此范围内,各防腐保鲜剂的加标回收率在85.65~106.50%之间,相对标准偏差为2.36%~6.78%。该方法中乙萘酚的检测限为0.5 mg/kg,对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、2,4-D、4-苯基苯酚和联苯醚的检测限为1.0 mg/kg。该方法简便,快速、准确、灵敏度高、重现性好,能满足柑橘中6种防腐保鲜剂残留量的检测要求。     

液相色谱-质谱测定蔬菜、水果中四种保鲜剂的残留量

为了建立HPLC-MS测定蔬菜、水果中保鲜剂多菌灵、噻苯咪唑、甲基硫菌灵、咪鲜胺残留量的方法.用甲醇-盐酸溶液提取试样中的保鲜剂,经固相萃取净化,以反相液相色谱分离、质谱检测器测定.四种保鲜剂的最低检测限分别为:多菌灵1.0μg/kg、噻苯咪唑、咪鲜胺2.0μg/kg、甲基硫菌灵5.0μg/kg.多菌灵回收率为92.8%～103.2%,相对标准偏差为2.27%～4.01%;噻菌灵回收率为90.9%～102.5%,相对标准偏差为2.44%4.17%;甲基硫菌灵回收率为74.9%～99.2%,相对标准偏差为2.97%～4.55%;咪鲜胺回收率为81.9%～97.6%,相对标准偏差为2.64%～4.49%.     

3 种杀菌剂在北京林地食用菌中的残留与安全性评价

在北京市林地食用菌基地采集不同品种食用菌,监测多菌灵、噻菌灵和咪鲜胺的残留水平。样品用乙腈提取,N-丙基乙二胺和弱阳离子交换吸附剂净化,超高效反相液相色谱分离,三重四极杆质谱检测,基质匹配标准溶液的外标法定量。在添加量为0.01～1.0 mg/kg时,方法的回收率为74%～100%,相对标准偏差为2%～13.0%,咪鲜胺、噻菌灵和多菌灵3 种农药的最小检出量分别为0.003、0.003、0.001 5 ng,最低检出浓度为0.01 mg/kg。林地食用菌样品中噻菌灵的残留量均小于0.01 mg/kg,多菌灵的残留量为0.01～0.42 mg/kg,咪鲜胺的残留量为0.01～0.51 mg/kg。我国规定多菌灵、噻菌灵、咪鲜胺在食用菌中的最大残留限量分别为1.0、5.0、2.0 mg/kg,以此为依据,北京林地食用菌中的多菌灵、噻菌灵和咪鲜胺残留是安全的。     

分散固相萃取-超高效液相色谱-串质谱法测定豆芽中10种植物生长剂和杀菌剂

建立了一种同时分析豆芽中10种植物生长调节剂和杀菌剂的分散固相萃取-超高效液相色谱-串联质谱法(UPLC-MS/MS)的检测方法。样品经过1%酸化乙腈提取,PSA、C_(18)、GCB吸附剂净化,UPLC-MS/MS多反应监测模式测定,外标法定量,检测结果显示:多菌灵、6-苄基氨基嘌呤、吲哚乙酸、赤霉素、恩诺沙星、2,4-二氯苯氧乙酸、多效唑、咪鲜胺、涕灭威和甲基托布津10种药物浓度在5.0~200.0μg/L范围内呈良好线性关系,相关系数均大于0.99,加标回收率为80.4%~99.8%,相对标准偏差(RSD%)为2.0%~7.8%,方法检出限为0.2~2.6μg/kg。该方法简单、快速、可靠。串联质谱法在很大程度上减少了基质干扰,减少了假阳性现象的产生。     

超高效液相色谱-串联质谱法同时测定水果中10种保鲜剂残留量

建立超高效液相色谱-串联质谱法同时测定水果中咪鲜胺、多菌灵、甲基硫菌灵、噻菌灵、异菌脲、抑霉唑、苯菌灵、腐霉利、百菌清、嘧霉胺10种保鲜剂残留方法。样品用Qu ECh ERS方法处理,经Acquity UPLC BEH C18色谱柱分离,乙腈-0.1%甲酸溶液为流动相梯度洗脱,经超高效液相色谱-串联质谱仪采用电喷雾电离源多反应监测模式检测,基质匹配标准溶液外标法定量。结果表明,10种保鲜剂在各自质量浓度范围内线性良好(r0.992),在3个加标水平下,回收率为75.0%～112%,相对标准偏差(n=6)不大于9.5%。10种防腐保鲜剂的检出限(R_(SN)≥3)为0.02～1.50 μg/kg,定量限(R_(SN)≥10)为0.1～4.1 μg/kg。该方法操作简便,灵敏度高,准确可靠,适用于水果中10种保鲜剂残留量的同时测定。     

不同保鲜剂对柑橘果实贮藏品质的影响

以纽荷尔脐橙、奉节72-1脐橙、夏橙3种柑橘果实为研究对象,分别在复合有2,4-dichlorophenoxyacetic acid(2,4-D)的壳寡糖、"活力鲜"保鲜剂、膜醭毕赤酵母(Pichia membranaefaciens)以及低剂量多菌灵+膜醭毕赤酵母4种处理液中浸泡后,晾干套袋,室温、低温(5℃)下贮藏,观察发病和品质变化情况。结果表明,与对照相比,各保鲜剂处理对柑橘果实都有不同程度的病害控制效果,其中"活力鲜"保鲜剂复合2,4-D处理效果最佳;多菌灵复合膜醭毕赤酵母和2,4-D处理的保鲜效果优于膜醭毕赤酵母复合2,4-D处理;各保鲜剂处理对果实可溶性固形物(Total Soluble Solid,TSS)、可滴定酸(Titratable Acid,TA)含量无明显影响;低温可显著延缓果实TSS含量、TA含量和重量的降低。     

QuEChERS-UPLC-MS/MS法测定鸡蛋中19种氨基甲酸酯类农药及其代谢物残留量

采用QuEChERS-超高效液相色谱-串联质谱法（UPLC-MS/MS）同时测定鸡蛋中的19种氨基甲酸酯类农药及其代谢物残留量。鸡蛋样品通过乙腈提取,分散固相萃取净化,UPLC-MS/MS测定。19种氨基甲酸酯类农药及其代谢物残留在0.2~50 ng/mL范围内线性良好（R2>0.999）,方法的检出限为1.0~10 μg/kg。在添加水平为10、20、50 μg/kg时,回收率为69.3%~107.6%,相对标准偏差低于9.21%。该方法简单快速,高效准确,回收率高,能够满足鸡蛋中19种氨基甲酸酯类农药及其代谢物残留检测与确证的需要。     

直接竞争ELISA法检测蔬菜中2,4-二氯苯氧乙酸

目的研究竞争性酶联免疫法分析测定蔬菜中2,4-二氯苯氧乙酸(2,4-dichlorophenoxyacetic acid,2,4-D)残留量。方法样品用乙腈进行前处理后采用ELISA试剂盒检测蔬菜中2,4-D的残留,分析方法的灵敏度、回收率和稳定性;并比较其与超高效液相色谱-质谱法(ultra performance liquid chromatography-mass spectrometry,UPLC-MS)在灵敏度、稳定性等方法学参数上的差异。结果经过有机溶剂提取等前处理过程,ELISA与UPLC-MS的检测灵敏度分别可以达到1.739μg/kg和3μg/kg,回收率分别为80.19%~117.37%和80.04%~112.5%;试剂盒稳定性的测定证明其可以在4℃至少保存8个月。结论与UPLC-MS法相比,直接竞争ELISA法简单、高效,检测快速,灵敏度高,适合大批量筛选样品。因此,ELISA法更加适合快速检测蔬菜中2,4-D的残留。     

超高效液相色谱-串联质谱法同时测定食品中7种防腐剂和4种甜味剂

目的:建立一种超高效液相色谱-串联质谱法(UPLC-MS/MS)同时测定食品中7种防腐剂(苯甲酸、山梨酸、脱氢乙酸、对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯、对羟基苯甲酸丁酯)和4种甜味剂(糖精钠、甜蜜素、安赛蜜、三氯蔗糖)。方法:样品经提取液提取(乙醇∶水=8∶2,体积比),用2.5mL乙酸锌和2.5mL亚铁氰化钾沉淀蛋白,加提取液定容至刻度,漩涡震荡10min,离心,取上清液进行测定。结果:本方法线性关系良好(r~2=0.9921~0.9995),检出限为0.5μg/kg~10μg/kg。在不同食品中3个浓度添加水平平均回收率为79.5%~107.1%,相对标准偏差为0.7%~6.5%。结论:该方法准确度高,结果稳定可靠,适用于食品中多种防腐剂和甜味剂的高通量检测。     

QuEChERS-高效液相色谱-串联质谱法同时测定儿童化妆品中的10种防腐剂

目的 建立QuEChERS-高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry, HPLC-MS/MS)同时测定儿童化妆品中10种防腐剂(碘丙炔醇丁基氨甲酸酯、对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯、对羟基苯甲酸丁酯、对羟基苯甲酸异丙酯、对羟基苯甲酸异丁酯、甲基异噻唑啉酮、甲基氯异噻唑啉酮以及脱氢乙酸)的分析方法。方法 儿童化妆品经超声及QuEChERS提取后, 用Agilent ZORBAX SB-C18 (10 cm?4.6 mm, 3.5 μm)色谱柱分离, 在高效液相色谱-串联质谱仪多反应监测模式下进行定性及定量分析。结果 10种防腐剂在0.5~500.0 μg/L范围内线性关系良好, 线性相关系数r大于0.999, 检出限为1.5~15.0 μg/kg, 平均回收率为81.5%~106.5%, 相对标准偏差均小于9.0%。结论 该方法简便、灵敏度高、回收率好, 适用于儿童化妆品中防腐剂的测定。     

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.