用HPLC法测定L-亮氨酸

研究采用高效液相色谱(HPLC)和邻苯二甲醛(OPA)柱前衍生法测定L-亮氨酸的条件。样品通过ODS C-18柱分离,流动相由60%的50mmol/L乙酸钠溶液和40%的甲醇构成,荧光检测器波长Ex为350nm、Em为450nm。回收率99.93%~100.35%,相对标准偏差为0.754%。     

小麦脱氧雪腐镰刀菌烯醇（DON）检测方法的研究

建立了一种新的小麦脱氧雪腐镰刀菌烯醇(DON)高效液相色谱检测方法。采用聚乙二醇和水对小麦样品进行振荡提取,提取液分别用活性炭、柱层析硅胶、中性氧化铝、酸性氧化铝、碱性氧化铝净化,比较几种吸附剂对小麦DON净化效果。结果表明,用酸性氧化铝净化效果最好,除杂率为66.3%,净化液通过0.22μm聚醚砜滤膜可直接用于HPLC检测;色谱条件:分离柱为C18柱;流动相为甲醇∶水(20∶80);波长为230 nm。三水平加标平均回收率为91.0%~103.7%,不同污染水平的小麦阳性样品精密度试验相对标准偏差(RSD)为2.3%~8.5%;与免疫亲和柱(IAC)净化方法比较,方法间误差为2.3%~8.4%。本方法具有操作简便、快速、准确、成本低,可满足小麦DON大宗样品定量测定的要求。     

富含色素类中药材中黄曲霉毒素的高效液相色谱-荧光检测方法研究

目的采用免疫亲和净化手段和高效液相色谱(HPLC)检测技术,建立富含色素类中药材中黄曲霉毒素(AFT)的测定方法,为中药材中AFT的检测和污染调查提供技术支撑。方法中药材样品经过高速粉碎均匀后,粉末状样品经80%甲醇水高速均质提取,提取液以磷酸盐缓冲液(PBS)稀释后,用免疫亲和柱(IAC)净化,以含吐温-20的PBS淋洗柱子后,用甲醇洗脱AFT,洗脱液经三氟乙酸衍生后用HPLC分析,C18反相色谱柱分离,用荧光检测器(FLD)测定,外标法定量。结果黄曲霉毒素G1、B1、G2和B2的最低检出限(LOD,S/N=3)分别为0.1、0.02、0.05和0.05μg/kg;以不含AFT、色素含量较高的枳实、绞股蓝、枇杷叶、鱼腥草和乌梅为基质,进行加标回收试验,加标水平为6.0~24μg/kg(以AFT总量计),AFT的平均回收率在62.3%~115%之间,RSD在0.92%~15.9%之间(n=3)。结论 IAC净化技术和HPLC-FLD相结合,用于4种AFT的检测可取得较为满意的结果,方法的准确度高、精密度好,各项指标均满足欧盟对食品中AFT检测的要求,方法可满足色素含量较高的中药材中4种黄曲霉毒素(AFT)的测定。     

高效液相色谱法测定蜂产品中链霉素残留量

采用双试剂柱后衍生法,在C18柱上以0.01mol/L 1-庚烷磺酸钠+乙腈为流动相及荧光检测器(Ex=263nm,Em=447nm)检测蜂蜜中链霉素的残留量,优化了蜂蜜样品的前处理方法和高效液相色谱条件,包括流动相组成和流速及衍生化试剂的处理,同时改善样品前处理过程中淋洗液和提取液的用量,并选用50%三氯乙酸作为沉淀剂,建立了一种更简便、快速、准确性和重现性好的链霉素检测方法。     

高效液相色谱荧光法测定印染废水中的二苯胺

建立了印染废水中微量二苯胺的高效液相色谱荧光检测方法。样品经HLB固相萃取小柱净化、浓缩后,在Kromasil C18色谱柱上以水/乙腈(体积比20/80)为流动相进行分离,采用荧光检测器检测,检测波长λex为265 nm,λem为350 nm。二苯胺在5.0~500.0μg/L范围内具有良好的线性关系,相关系数0.999,回收率为92.3%~104.2%,相对标准偏差(RSD)为1.2%~4.1%,方法的定量检出限(LOQ)为2.5μg/L。通过试验条件优化建立的方法干扰少、灵敏度高,适用于印染废水中二苯胺的检测。     

固相萃取柱高效液相色谱法检测粮食中玉米赤霉烯酮

建立固相萃取柱净化、高效液相色谱检测粮食中玉米赤霉烯酮方法。样品经乙腈—NaCl溶液(90:10,V/V)超声波提取,固相萃取柱净化,甲醇-水(70:30,V/V)为流动相,流速1 ml/min;荧光检测器检测,激发波长274 nm、发射波长440 nm;柱温30℃;进样量10μl。玉米赤霉烯酮浓度在10～600μg/L范围呈线性,线性回归方程为:Y=5.86 x+23.25,相关系数为0.9997;方法检出限为5μg/kg;3个不同水平加标平均回收率为80.4%～88.5%,相对标准偏差(RSD)为2.5%～5.4%。该法选择性高、净化效果好、操作简单、检测效果理想,适于大批量样品检测,有利于推广。     

全自动在线免疫亲和固相萃取-高效液相色谱法快速测定食品中的黄曲霉毒素

目的建立一种全自动在线免疫亲和柱固相萃取-高效液相色谱(online immunoaffinity solid phase extraction-high performance liquid chromatography,online-IA-SPE-HPLC)快速测定食品中黄曲霉毒素(aflatoxins,AFT)。方法样品经乙腈-水提取后,经可重复使用的在线免疫亲和小柱进行富集与净化,经C_(18)色谱柱(150mm×4.6 mm,5μm)进行分离,用特定流动相进行洗脱,用电化学衍生KOBRA~?Cell荧光检测器进行检测,激发波长为362 nm,发射波长为455 nm,同时进行线性范围、精密度、准确度和加标回收率等方法学验证。结果对于大米、食醋、酱油和花生油等基质,该方法对AFT B_1的检出限均为0.035μg/kg,低于我国现行食品安全标准对AFT B_1的限量要求;AFT B_1及AFT G1在25~500 ng/L范围内具有良好的线性,AFT B_2及AFT G_2在6.25~125 ng/L范围内具有良好的线性,相关系数均为0.9999;在低、中和高3水平加标下大米、食醋、酱油和花生油中的4种黄曲霉毒素回收率在91.16%~109.99%之间,精密度为0.52%~4.39%。结论该方法的前处理快速、简易,方法重现性好、灵敏度高,适用于食品中AFT的高通量检测。     

分子印迹固相萃取–高效液相色谱法的优化及在测定植物油中苯并(a)芘含量的应用

建立优化的分子印迹固相萃取超高效液相色谱法测定植物油中苯并芘的检测方法。实验过程中通过对样品不同固相萃取净化效能、最佳检测波长、流动相体系及色谱柱使用的考察,结果表明,分子印迹固相萃取净化柱比较适合植物油样品的前处理萃取及净化,最佳检测波长为激发波长365 nm和发射波长410 nm,苯并芘色谱峰在此条件下具有较高的响应值和信噪比,在90%乙腈–10%水流动相体系下,目标峰具有较好的分离效果,采用150 mm的短柱子能有效提高工作效率。苯并芘在浓度0.3~20 μg/L范围内具有良好的线性关系,相关系数大于0.999 9,方法检出限为0.05 μg/kg,定量限为0.10 μg/kg,3个添加浓度水平的平均回收率为87.6%~95.9%,相对标准偏差为1.08%~2.16%。实际样品检测中,苯并芘的检出率为39.0%,超标率为2.4%,合格率为97.6%。该优化方法灵敏度高,操作便捷,快速准确,可适用于植物油中苯并芘的批量检测及污染监测情况分析。     

HPLC-UV-FL串联法测定染色废水中的苯胺

利用固相萃取-高效液相色谱紫外荧光串联建立了染色废水中苯胺的检测方法。样品经MCX固相萃取小柱提取、净化后,采用Kromasil C18柱(250 mm×4.6 mm,内径5μm)分离,水/乙腈(20/80,体积比)为流动相,紫外检测波长为235 nm,荧光检测波长:λex为225 nm,λem为335 nm,外标法定量。试验结果显示,荧光检测条件下,苯胺在0.001~0.500 mg/L范围内呈良好的线性关系,最低检出限LOD为0.001 mg/L,定量检出限LOQ为0.003 mg/L。紫外检测条件下,苯胺在0.02~5.00 mg/L范围内呈良好的线性关系,最低检出限LOD为0.02 mg/L,定量检出限LOQ为0.06 mg/L,方法回收率在95.6%~101.8%,RSD为2.2%~5.2%,能满足测定要求。     

皮革中2-巯基苯并噻唑含量的HPLC测试

建立了皮革中2-巯基苯并噻唑(MBT)含量的液相色谱(HPLC)测试方法。采用超声波辅助乙腈对样品进行萃取,重复萃取1次,萃取时间60min,萃取液经膜过滤后,采用带预净化柱的HPLC进行测试,检测波长λ=320nm,流动相为v(乙腈)/v(水)=70/30,等梯度洗脱。方法的检测限为10mg/kg,回收率在93%~103%之间,精密度在3%~9%之间。对20块皮革样品中MBT含量进行测试,样品检出率为30%,含量在37~137mg/kg之间。     

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.