Determination of hydrogen peroxide in food

利用猪血红蛋白(PHb)的催化特性,以3,3',5,5'-四甲基联苯胺(TMb)为底物,建立了一种催化光度终止法测定食品中残留过氧化氢(H2O2)的方法。实验考察了终止剂的类型和浓度、反应时间、PH、温度、TMb浓度对H2O2检测的影响。在选定的反应条件下,体系吸光值与H2O2浓度在1.46x10-6~2.91x10-5MOl/l范围内呈良好的线性关系,线性相关系数为0.9958,方法对H2O2的检出限为5x10-7MOl/l,测定标准偏差为4.9%,样品的加标回收率为92.9%~103%,利用该方法进行了实际样品中的H2O2分析,结果与国标法无显著性差异。A new spectrophotometric method was developed for the determination of hydrogen peroxide(H2O2) in foods using 3,3′,5,5′-tetramethylbenzidine(TMB) as a terminating agent in the catalytic reaction between hemoglobin porcine(pHb) and H2O2.The influence of terminating agents,reaction time,pH,temperature and the concentration of TMB was discussed.Under the optimal experimental conditions,the absorbance value was linearly correlated to H2O2 concentration in the range of 1.46×10-6～2.91×10-5 mol/L with the correlation coefficient of 0.9958.The detection limit was found to be 5×10-7 mol/L and RSD was 4.9 %.The recoveries in the range of 92.9 %～103 % were obtained.The determination results corresponded well with those by the national standard method

Consideration and Suggestion to Ways to Develope Efficient Agricul ture in Arid Hilly Area of South Ningxia

In the middle ages of 1970’s ,Northwestern institute of soil and water conservation carried out scientific inves-tigation and started long term field experiement and demonstration in arid hilly area of the south Ningxia under thesupport of Chinese goverment. Based on deep and systematic studies, from the policy of production construction topractical technology of efficient agriculture , followsnig comprehensive development strategies and technologicalmeasures have been proposed:″planting grass and shrub at ...７０年代中期，我所受中央领导同志指示，在宁夏南部山区开展科学考察，并开始了长期定位试验研究和示范。从生产建设方针到实用高效农业技术，进行了深入系统的研究，先后提出了“草灌先行”、“出路在肥”、“优化结构”、“旱作增产体系”、“节水型早实丰产果园建设技术”等一批具有全局性的发展战略和技术措施。在此基础上，对本区发展高效农业的途径和基本战略进行了研究探索，认为“三缺”（缺水、缺科技、缺物质投入）是三大障碍因素，其中又以缺乏科技人才与资金是主要限制因子。因而采取“把握全局、统筹兼顾、重点突破、梯级推进”的发展战略，大力推广行之有效的实用高效增产技术，着力发展支柱产业，培育市场经济，对经济的快速发展和奔小康具有重要意义

Application of Polymethylphenylsiloxane-coated SPME Fiber for Pesticide Analysis in Vegetables

通过合成羟基聚甲基苯基硅氧烷(PMPS-OH)材料,制备固相微萃取(SPME)纤维涂层。通过与商品化聚二甲基硅氧烷(PdMS)、聚丙烯酸酯(PA)和PdMS/聚二乙烯基苯(dVb)纤维对六六六异构体(α,β,γ,δ-bHC)、ddT及其衍生物(P,P′-ddd,P,P′-ddE,O,P′-ddT,P,P′-ddT)、联苯菊酯、甲氰菊酯、高效氟氯氰菊酯、三氟氯氰菊酯、氯氰菊酯和氰戊菊酯等选定农药萃取效果的比较,所制备的PMPS-OH纤维具有更好的萃取效率。对SPME实验条件进行了研究和优化,测定方法对各种农药的线性范围多在0.01--2 ng/g之间,相应的检出限在0.001--0.05 ng/g范围,回收率在50.5%--103%。方法已被应用于蔬菜样品中农残的检测。Hydroxyl-terminated polymethylphenylsiloxane(PMPS-OH) was synthesized and successfully used as a novel coating for solid-phase microextraction(SPME).PMPS-OH coated fiber was applied to the analysis of pesticides including α,β,γ,δ-BHC,p,p′-DDD,p,p′-DDE,o,p′-DDT,p,p′-DDT,bifenthrin,fenpropathrin,β-cyfluthrin,cyhalothrin,cypermethrin and fenvalerate by SPME-GC-ECD.The extraction efficiencies of the PMPS-OH coated fiber for selected pesticides were found to be higher than those of commercial fibers,such as PDMS,PA and PDMS/DVB.The SPME experimental conditions including stirring rate,extraction temperature and time,were studied,and the optimal conditions were established.The linearity for the target pesticides was from 0.01 to 2 ng/g,and the detection limits were between 0.001 and 0.05 ng/g.The proposed approach was applied to the determination of pesticides in vegetable samples,and the recovery for the pesticides spiked in vegetables at 4 ng/g ranged from 50.5% to 103%.福建省自然科学基金(No.2006J0393);福建省科技计划重点项目(No.2007Y0032

Preparation of multi-walled carbon nanotubes coated solid-phase microextraction fiber and its application on the analysis of polybromobiphenyls in seawater

通过以nAfIOn为黏合剂、不锈钢丝为涂层载体,制备了多壁碳纳米管固相微萃取纤维.该纤维的制备方法快速、简便、成本低,并具有热稳定性好(300℃)、使用寿命长(>100次)、对多溴联苯萃取效率高等特点.研究优化了影响萃取及分离效率的解吸温度和时间、萃取时间、搅拌速度、盐度等实验条件,进行了海水中多溴联苯的测定.对一溴联苯的线性范围为0.1~5.0ng/Ml,而二溴联苯、三溴联苯、四溴联苯和五溴联苯的线性范围均为0.01~5.0ng/Ml.方法的检测限为0.1~0.8ng/l.在优化的条件下分别测定了0.1和1ng/Ml多溴联苯的海水加标样品,回收率在91.1%~107.3%之间,相对标准偏差小于12%.该方法分析时间短、灵敏度高、操作简便,适用于水样中多溴联苯的痕量分析.In this study, we proposed an approach using Nafion as a binder to immobilize multi-walled carbon nanotubes (MWCNTs) on a stainless steel wire base to prepare MWCNTs-coated fiber.The preparation method is fast, simple and low-cost.The MWCNTs-coated fiber shows high affinity towards polybromobiphenyls (PBBs), and mechanical and thermal stability.The experimental parameters related to extraction efficiency including desorption temperature and time, extraction time, stirring rate, salt concentration were investigated and optimized.The linearity was found to be from 0.1 to 5.0 ng/mL for monobromobiphenyl (mono-BB), and 0.01 to 5.0 ng/mL for dibromobiphenyl (Di-BB), tribromobiphenyl (Tri-BB), tetrabromobiphenyl (Tetra-BB) and pentabromobiphenyl (Penta-BB).The detection limits of these PBBs were between 0.1 and 0.8 ng/L.The recovery of the PBBs spiked in sea water at 0.1 ng/mL and 1 ng/mL ranged from 91.1% to 107.3%, and the relative standard deviations were less than 12%.The proposed method which is sensitive, fast and easy to operate could be applied to the determination of trace-level PBBs in water samples.福建省自然科学基金(批准号:2006J0393);福建省科技计划重点项目(批准号:2007Y0032;2009Y0045);福建省南平市科技计划项目(批准号:NP2006Z1-1)资

Sol-gel coating for solid phase microextraction and its applications in pesticide residue analysis

利用溶胶-凝胶(SOl-gEl)技术制备固相微萃取(SPME)涂层材料。通过硅醇盐前驱体与涂层聚合物羟基硅油(OH-TSO)的水解共聚的方法,成功地制备了聚二甲基硅氧烷SOl-gEl涂层的SPME萃取头,并以农药的混合标准水溶液为研究对象,用直接-固相微萃取-气相色谱法(gC)对涂层的性能进行考察,制成的萃取头适用于多种农药残留的萃取分离分析。A sol-gel material was successfully applied to preparing a novel coating as a precursor for solid phase microextraction(SPME).A homemade fiber based on solgel polydimethylsiloxane(PDMS) SPME coating was prepared by hydrolysis of alkoxide precursors and subsequent polycondensation with OH-TSO.The characteristics of the new coating were investigated by the analysis of pesticide standard solution mixture in conjunction with gas chromatograph(GC).The proposed fiber presented a wide linear range for target analytes,and exhibited high sensitivity and high thermal stability in applications.福建省自然科学基金(2006J0393);福建省科技计划重点(2007Y0032)项目;福建省南平市科技计划(N2006Z01-1)项目资

Cellor Agriculture Is A New Way in Developing Efficient Agriculture in Dryland Hilly Region

窑窖农业是建立在利用雨水资源基础之上发展起来的集流农业，它经历了三个阶段：雨养农业、径流农业、窑窖农业。在固原试验区的试验与应用中，“窑窖农业”在干旱山区的高效农业建设中已显示出强大生命力，充分证明它是发展干旱山区高效农业的一条新路