超高效液相色谱快速测定粮食中黄曲霉毒素含量

建立了免疫亲和柱净化-超高效液相色谱法快速测定粮食中黄曲霉毒素的检测方法。样品经粉碎,70%甲醇提取后,用免疫亲和柱净化、氮吹浓缩,采用C18色谱柱(50 mm×3 mm,1.7μm)分离。以甲醇-水(V甲醇∶V水=45∶55)为流动相,流速为0.2 m L/min,进样量为2μL,荧光检测器检测,激发波长为360 nm,发射波长为440 nm,无需衍生。黄曲霉毒素B_1、B_2、G_1、G_2的保留时间小于5 min,从样品前处理到结果分析整个过程小于45 min。根据3倍信噪比(S/N)的峰响应值,确定黄曲霉毒素(B_1、B_2、G_1、G_2)检出限分别为0.090、0.020、0.019、0.030μg/kg,定量限分别为0.030、0.007、0.065、0.011μg/kg,4种毒素分别在2.00~50.00、0.48~12.00、1.12~28.00、0.48~12.00μg/kg范围内呈线性相关,相关系数R值分别为0.999 99、0.999 99、0.999 99、0.999 97;在玉米样品中加标回收率为93.9%~104.4%。该方法无需衍生即可同时测定粮食中4种黄曲霉毒素,适用于粮食中黄曲霉毒素的快速定量测定。     

免疫亲和柱同时净化-HPLC法测定高粱中黄曲霉毒素和玉米赤霉烯酮

建立了免疫亲和柱同时净化一高效液相色谱法检测高梁中的黄曲霉毒素B1、B2、G1、G2和玉米赤霉烯酮的分析方法。样品用70％甲醇水溶液提取,经免疫亲和色谱柱净化,应用液相色谱法检测黄曲霉毒素B1、B2、G1、G2和玉米赤霉烯酮。黄曲霉毒素B1、B2、G1、G2方法的定量限均为0．2μg／kg,玉米赤霉烯酮方法的定量限为10．0μg／kg,相对标准偏差低于7．71％,回收率为76．3％～105％。     

粮食中黄曲霉毒素含量快速色谱测定方法研究

建立了一种使用岛津超高效液相色谱仪LC-30A无需衍生快速测定粮食中黄曲霉毒素的方法.结果表明：黄曲霉毒素G1、B1线性范围0.2～50 μg/L,G2、B2线性范围0.06～15 μg/L,相关系数均大于0.9999;进样量2μL,仪器检出限为0.002～ 0.019 μg/L,仪器定量限为0.007～0.065 μg/L;3个浓度（G1、B1为0.5、2、10 μg/L,G2、B2为0.15、0.6、3μg/L）标样6次连续进样的保留时间和峰面积相对标准偏差分别在0.11％～0.39％和0.13％～1.34％;玉米样品3个浓度加标回收率为88.8％～108％.     

粮食中伏马毒素B1、B2的免疫亲和净化超高效液相色谱测定

建立了免疫亲和柱净化-超高效液相色谱法快速测定粮食中伏马毒素B1、B2的检测方法.样品经提取后,用免疫亲和柱净化、浓缩,Waters Acquity UPLC BEH C18(50 mm×2.1 mm,1.7 μm)色谱柱分离,以甲醇/磷酸二氢钠溶液(77/23,v/v)为流动相、流速为0.2 mL/min、进样量为1μL,用Acquity荧光检测器激发波长为310nm、发射波长为435 nm处进行检测,无需衍生,伏马毒素B1、B2的保留时间小于6.5 min,从样品前处理到分析整个过程小于45 min.根据3倍信噪比的峰响应值,确定伏马毒素B1、B2的检出限为0.05 ng,在0.25～10.0 ng范围内呈线性相关,相关系数R2值分别为0.9972和0.9999;FB1和FB2在粮食样品中加标回收率分别为70.0％～100.5％和74.8％～96.0％,精密度分别为2.2％～5.5％和4.3％～7.4％.本方法简便快速、灵敏度高、重现性好、溶剂用量少,适用于粮食中伏马毒素B1、B2的快速测定.     

时间分辨荧光免疫层析法测定粮食中的黄曲霉毒素B_1

采用时间分辨荧光免疫层析试纸条及配套的荧光定量分析仪,对粮食中黄曲霉毒素B_1的快速检测进行了研究。结果表明,该方法的检出限为0.8μg/kg,定量限为2.6μg/kg,不同水平的加标回收率在94%～108%。选取标准质控样品进行测试,液相色谱法检测结果与该方法结果基本一致。该方法准确可靠,操作简便,适用于粮食中黄曲霉毒素B_1的快速检测。     

高效液相色谱法测定黄曲霉毒素B1的不确定度评定

采用柱后衍生高效液相色谱法测定油脂中黄曲霉毒素B1,对油脂中黄曲霉毒素B1测量的不确定度进行分析评定,分别对测定过程中样品制备、样品称量、测量重复性、标准溶液配置、样品提取、定容、检测方法以及仪器设备等影响因素进行分析评定.实验表明样品的均匀性、标准溶液的配制和提取回收率对测量结果的影响最大.     

超高效液相串联质谱检测玉米中5种真菌毒素的方法研究

本文旨在使用同一种提取方法同时提取玉米中5种真菌毒素,并用超高效液相串联质谱法进行样品检测。通过对提取方法的优化以及对优化方法准确度等的确认,最终确定了使用100%乙腈提取并进行分样处理[伏马毒素B1(FB1)使用50%乙腈复溶后上机]的过程。使用该方法对玉米中脱氧雪腐镰刀菌烯醇(DON)、3-乙酰基脱氧雪腐镰刀菌烯醇(3-AcDON)、玉米赤霉烯酮(ZEN)、黄曲霉毒素B1(AFB1)、伏马毒素B1(FB1)这5种真菌毒素进行检测,可达到方便快捷、准确可靠的目的。     

小麦中赭曲霉毒素A含量测定方法的改进研究

目的:优化GB 5009.96-2016中赭曲霉毒素A检测的前处理方法和色谱条件,以适应大批量样本的检测。方法:样品经甲醇:水(V∶V=80∶20)漩涡提取、免疫亲和层析净化,超高效液相色谱法测定。色谱条件为Thermo Scientific Hypersil GOLD C18反相柱(100mm×2.1mm,粒径1.9μm),流动相为1%乙酸水-乙腈(V∶V=60∶40),流速为0.25m L/min,进样量4μL,柱温:25℃,荧光检测激发波长333nm,发射波长460nm。结果:赭曲霉毒素A在1.00~20.00ng/m L时具有良好的线性关系,相关系数R2=0.999 7,加标回收率为82.9%~90.1%,精密度RSD5.1%~6.1%。本方法实验用时和流动相用量分别比国标法减少72.8%和87.5%。结论:本方法适用于小麦中赭曲霉毒素A含量的测定且更灵敏、高效和环保。在大批量样品分析中可有效节约时间、材料成本。     

乙基多杀菌素的高效液相色谱测定

建立了用高效液相色谱法测定稻谷中乙基多杀菌素残留量的方法。样品经溶剂提取处理,经Pesticarb/NH2固相萃取柱净化,乙腈-甲苯(3∶1,V/V)洗脱、氮气吹干、流动相定容后,进HPLC分析测定。结果表明:乙基多杀菌素在50～500μg/mL范围内线性良好,相关系数达0.9999,在稻谷样品中3个加标水平的平均回收率为96.35%～98.9%,相对标准偏差为0.2660%～0.8225%。最后采用液质联用方法对目标化合物进行验证。     

呕吐毒素胶体金三线定量检测条性能研究

为验证呕吐毒素胶体金三线定量检测条的性能,采用胶体金三线定量检测条和HPLC法对多种谷物样品进行检测,并对检测结果进行分析研究。结果表明,该方法检出限为118μg/kg,定量限为316μg/kg,检测结果与HPLC法无显著差异且相关性非常好。为了验证该方法的重复性,6个参与测试人员在相同实验室,按照同一方法,采用不同设备,检测相同样品,变异系数为4.7%~19.6%,平均变异系数为11.8%。为了验证该方法的特异性,选择DON结构类似物和其他5种生物毒素的标准品在阴性玉米中进行添加,添加浓度为1 000μg/kg,结果表明,呕吐毒素胶体金检测条对伏马毒素、赭曲霉毒素、黄曲霉毒素、玉米赤霉烯酮无交叉反应。因此,呕吐毒素胶体金三线定量检测条能满足粮食中呕吐毒素测定的要求,易于推广应用。     

Price transmission between products at different stages of manufacturing in forest industries

The theory of demand and supply implies a positive relationship, or “price transmission” between the prices of products at different stages of manufacturing. This relationship was investigated with quarterly prices of softwood stumpage in the US South, and national prices of forest products, from 1977 to 2002. All prices, net of inflation, were found to be nonstationary and there was no evidence of co-integration between prices. Vector autogressive models, augmented by Granger causality tests and multiplier analysis showed that there was a one-to-one permanent positive response of the southern sawtimber stumpage price to a permanent change in the national lumber price. There was also a one-third permanent positive response of the national paper price to a permanent change in the national pulp price. There was no relation between regional pulpwood prices and national pulp or paper prices. When price transmission was significant, the full adjustment took about 2 years.     

The Effect of the Structural Adjustment Program on the Output,Prices and Exports of Major Agricultural Export Crops in Nigeria

The primary objective of this paper is to examine changes in the level of output, prices and exports of major export crops resulting from the Structural Adjustment Program (SAP) in Nigeria. THere two main sources of data: the Central Bank of Nigeria (CBN) through its annual reports, Economic and Financial Review, and the Nigerian Federal Office of Statistics (FOS) through its Trade Summaries. Although the SAP led to appreciable increases in output and producer prices, its effects on exports were insignificant. The implications of these for the implementation of the program are explored.     

Application of an ecosystem function framework to perceptions of community woodlands

Owners, local residents, government, and conservation organisations can express divergent preferences in the development and management of local woodlands. The perceptions of these four groups were examined, in the context of three community woodlands in Eastern England, using an ecosystem function framework. In a pilot study, residents were able to allocate a relative importance to woodland ecosystem services which were then related to “regulation”, “habitat”, and “production” or “information” functions. However residents also placed importance on negative services or “dis-services” associated with the woodland ecosystem. Therefore a fifth category of “dis-services” was included in the main survey which included 84 local residents, three woodland owners, three government institutions, and six representatives from conservation groups. Each of the four groups placed greatest importance on services associated with habitat (16–39% of the total importance) and information (30–50%) functions suggesting, in this example, mutual interest in the use of woodlands as a habitat or recreational resource. By contrast a potential area of difference was the particularly high importance placed by one owner on dis-services such as fly tipping. In addition the woodland owners placed higher importance (10–20%), than local residents and conservation groups (7–9%), on the productive services of the wood. This suggests a need for communication when production-related operations affect recreation. The ecosystem function framework appears to be a useful approach for highlighting potential tensions and areas of mutual interest in the management of semi-natural ecosystems.     

In Vino ‘No’ Veritas: impacts of fraud on wine imports in China

China is one of the largest wine importing countries in the world and is poised for continued import growth in the future. Increased wine purchases throughout China have given rise to persistent fraud where fake wines are packaged and sold with counterfeit contents and labels. For exporting countries like France, counterfeit wines displace market share, damage foreign brand reputation, and cause distrust in consumers who are aware of counterfeiting problems throughout the country. We examine the impact of fraudulent wine events (as measured by negative media reports) on Chinese wine demand differentiated by supplying country. We employ the Rotterdam demand system and a switching regression procedure to estimate import demand and compare results across different media variable specifications. Results consistently show that negative reports disproportionately affect French wine regardless of how the media variable is specified. This is not surprising because most fraudulent events involve French wine counterfeits.     

Revealing different understandings of soil held by scientists and farmers in the context of soil protection and management

This paper aims to analyse and draw together results from similar studies in England, Switzerland and France which investigated farmers’ understanding of soil and compared it with that of scientists, researchers and advisors (collectively called scientists in this analysis). A range of methods were used across the three studies and different theoretical approaches, looking at forms of knowledge, local practice of knowledge production and conceptions of reality, were employed to explain the results. Despite the different contexts, methodologies and theoretical approaches in the three studies, the results reveal similar patterns of difference in farmer and scientist understanding of soil. In the English study, farmers demonstrate a ‘know-how’ form or intuitive working knowledge of soil while advisors rely on scientifically established forms of ‘know-why’ and seek to understand and explain soil processes. Similarly in the Swiss study farmers’ and scientists’ differing perceptions are directed and shaped by their respective aims, methods and context of work. In the French study, farmers and researchers are shown to have different conceptions of soil, they attribute different meaning to the same activities, and use different words and language to describe the same features. In all three studies understanding is shown to be cultural and contextual, as such an integrative theoretical framework is proposed.     

An evaluation framework for earthquake-responsive land administration

In recent years earthquakes and their secondary hazards have claimed the largest number of lives of all large natural disasters. Some of the world’s most earthquake-prone zones are also areas of high population density. The impact is magnified by vulnerability factors including non-enforcement of building codes, knowledge gaps, urban poverty and poor governance capacity to manage and reduce earthquake risks. Poor security of land tenure and property rights increases the vulnerability of people and affects their ability to respond to natural disasters.Earthquake recovery and reconstruction provides very significant challenges for land agencies, with these challenges differing from one country to the next due to differences in the local context. Drawing on contrasting case studies in Haiti, Nepal and New Zealand this paper identifies the common post-earthquake land administration functions and challenges that may apply to many contexts. These lessons provide land agencies and other key stakeholders with a summary of the challenges an earthquake poses for land administration at different post-disaster stages. We also discuss the policy and regulatory, institutional, operational and preparedness lessons for land administration. From these lessons we propose a framework for evaluating the earthquake-responsiveness of a land administration system. This framework can be used by a land agency in an earthquake prone region, or where an earthquake has recently occurred, to assess what challenges to land administration might occur in the event of an earthquake, and the preparedness of their land administration system.     

森林生物多样性评价模型的改进

针对2002年的评价模型中的不足,提出了新的改进后的森林生物多样性变化的评价模型,并在我国第六次森林资源清查(1999～2003)资料的基础上,对1973～2003年我国森林生物多样性的变化进行了补充评价。评价结果表明:我国森林生物多样性的压力越来越大,压力指数由1973年的100,上升到2003年的199.10,上升了1.99倍;森林物种多样性总体的下降趋势已有一定幅度的改变,森林物种多样性指数增加了31.12%。森林生态系统多样性和森林生物多样性先逐渐上升,尔后又下降,第六次森林资源清查时又有所恢复,并分别上升了4.67个百分点和17.90个百分点。     

转变地质工作发展与服务方式的实践和建议

天津市地矿局注重加快转变经济发展方式,发挥地质工作优势,推进低碳清洁能源的开发利用创新和技术进步,紧紧依托地质工作的人才、技术和行业优势,加大清洁环保资源的勘查、研究、开发、利用。针对天津市水资源缺乏的情况,积极加强后备和应紧水源勘查。按照“两种资源,两个市场”的思路,通过实施中外合作勘查项目,以境外勘查工作为载体和平台,实施引进来和走出去战略,为天津市经济社会发展提供地质技术支撑。     

Trust-A monolithic panacea in land use planning?

Although trust research has been extensive and substantial, the constitution and actual merits of trust in land use planning remain nebulous. What do participants of a local land use planning process actually mean when they say they trust the planning committee? How important is participants’ trust in the planning committee in shaping their perceptions of the planning process and their cooperation in it? To explore the everyday meaning of trust in the specific context of local land use planning, semi-structured interviews with the participants of a local planning project in Switzerland were conducted (n = 9). Based on these results, the constitution and the relevance of trust in the responsible planning committee among a wider circle of participants were assessed (n = 66). The results show that participants trust the planning committee if they perceive its members as competent, honest, open, fair, reliable, reciprocating, respectful and committed. Interestingly, a considerable part of trust in the planning committee hinges explicitly on whether the committee incorporates the personal interests of the participant. Trust is indeed vital to participants’ belief that a meaningful discussion and cooperation with the members of the planning committee is possible. However, trust is neither a guarantee for people's approval of planning decisions nor for their cooperation. One implication of the findings is that in order to evaluate trust-building practice comprehensively, it is necessary to first understand the specific everyday meaning of trust for ‘real people’ in real planning processes.     

Agrarian Poverty,Nutrition and Economic Class – A Study of Gujarat,India

This paper analyses poverty and calorific undernourishment in the Indian state of Gujarat, where high and market‐led industrial growth has resulted in rapid economic improvement. The study is carried out through a combination of secondary and survey‐based data. We conclude that the neoliberal agenda of uncontrolled, outward‐looking growth has not resulted in significant reduction of poverty or malnourishment in rural areas. Furthermore, while land ownership is officially used as a proxy for wealth distribution, class position appears a better predictor of poverty status in the rural areas than landownership per se. At the policy level, there is a need to revive the agrarian economy and create new non‐agricultural assets, and the primary focus in the state must shift to the distribution of created assets rather than a single‐minded focus on growth.