高效液相色谱法测定保健食品原料和产品中角鲨烯的含量

目的建立高效液相色谱法测定保健食品和保健食品原料中角鲨烯的含量。方法样品经乙腈提取,经过Waters Xbridge C18色谱柱分离以甲醇为流动相,流速为1.0 mL/min,柱温为40℃,在紫外检测器210 nm波长下测定角鲨烯的含量。结果当角鲨烯浓度在0.5～300μg/mL范围内线性良好(r=0.9999),方法检出限为0.719mg/kg,方法定量限为2.398mg/kg,相对标准偏差为3%,在复杂基质中方法平均回收率为92.4%,在单一基质中方法平均回收率为114.9%。使用市售样品和原料对该方法进行验证,检测值在商品标识值的97%～106%范围内。结论此方法操作便捷,适用性广,验证结果良好,适合对保健食品和保健食品原料中角鲨烯的含量检测。     

微波消解-电感耦合等离子体质谱法同时测定沙棘汁饮料中18种无机元素

目的建立微波消解-电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)同时测定沙棘汁饮料中18种无机元素的方法。方法采用微波消解法对沙棘汁饮料样品进行处理,采用ICP-MS法测定,对前处理过程和仪器条件进行了优化,对方法性能进行考察,并将该方法用于4批市售沙棘汁样品中18种元素含量的检测。结果该方法线性范围宽,线性关系良好(r0.995),精密度高,18种元素的加标回收率为96.4%～107.3%,相对标准偏差(relative standard deviation, RSD)为0.3%～5.9%。结论微波消解-ICP-MS法前处理过程简单,分析时间短,方法快速、准确、可靠,能够满足沙棘汁中多种元素同时检测的需要。     

Geometry-Aware ICP for Scene Reconstruction from RGB-D Camera

The Iterative Closest Point (ICP) scheme has been widely used for the registration of surfaces and point clouds. However, when working on depth image sequences where there are large geometric planes with small (or even without) details, existing ICP algorithms are prone to tangential drifting and erroneous rotational estimations due to input device errors. In this paper, we propose a novel ICP algorithm that aims to overcome such drawbacks, and provides significantly stabler registration estimation for simultaneous localization and mapping (SLAM) tasks on RGB-D camera inputs. In our approach, the tangential drifting and the rotational estimation error are reduced by: 1) updating the conventional Euclidean distance term with the local geometry information, and 2) introducing a new camera stabilization term that prevents improper camera movement in the calculation. Our approach is simple, fast, effective, and is readily integratable with previous ICP algorithms. We test our new method with the TUM RGB-D SLAM dataset on state-of-the-art real-time 3D dense reconstruction platforms, i.e., ElasticFusion and Kintinuous. Experiments show that our new strategy outperforms all previous ones on various RGB-D data sequences under different combinations of registration systems and solutions.

     

保健食品中格列本脲含量测定的能力验证研究

目的设计组织保健食品中格列本脲含量测定能力验证项目,评价实验室检测保健食品中格列本脲的技术能力和水平。方法对考核样品通过实施能力验证计划,来自27个省(自治区)、直辖市80家实验室的测定结果进行稳健统计分析,通过稳健Z比分数评价实验室检测能力。结果考核样品中的格列本脲在P0.05显著水平时是均匀的,且在整个计划周期内稳定,满足能力验证的要求。在80家参加实验室中,满意结果数为68家,满意率为85.0%;可疑结果数为6家,可疑率为7.5%;不满意结果数为6家,不满意率为7.5%。结论多数参加的实验室检测能力结果满意,表明保健食品中格列本脲检测水平总体良好。     

毛细管电泳在食品安全检测中的应用进展

“民以食为天,食以安为先。”作为一个全球性问题,食品安全不仅影响每个人的健康水平与生活质量,更关乎整个国家的经济与发展。近年来,“毒奶粉”、“地沟油”、“染色馒头”、“毒豆芽”等频繁发作的食品安全恶性事件引起了社会的极大关注,也使人们对食品安全检测的需求进一步提高。而食物种类多样、成分复杂、及加工工艺繁琐等特点也为食品安全检测技术和方法带来了更大的难度和挑战。众多检测方式中,毛细管电泳（CE）以分析成本低、样品用量少、分离模式灵活多样、对环境污染小等优势被广泛应用。本文综述了2015年以来CE在食品安全检测中农药残留、兽药残留、多种食品添加剂、食品包装材料中双酚A和塑化剂等多个方面的分析应用,并对其未来的发展方向作了简要的展望。     

超高效液相色谱-串联三重四级杆质谱法测定富硒食品中的硒代氨基酸

目的建立一种用于检测富硒食品中4种硒代氨基酸的超高效液相色谱-串联质谱法。方法考虑3种样品前处理方法的影响,采用0.1%的甲酸(A)和乙腈(B)二元流动相体系对N-乙酰-L-硒代蛋氨酸、Se-(甲基)硒基-L-半胱氨酸、硒代蛋氨酸和硒代胱氨酸等4种硒代氨基酸进行色谱分离。采用多反应监测模式(multiple reaction monitoring,MRM)进行监测,基质匹配外标法进行定量。结果口服液中,4种硒代氨基酸的线性关系良好(r0.996),平均回收率范围为89.0%~104.5%,相对标准偏差均小于7%。结论该方法对简单基质的样品中硒代氨基酸的测定结果准确可靠,但基质效应较为明显。     

电子鼻技术在肉类品质应用中快速分析初探

电子鼻技术是近年发展起来的一种新型仿生嗅觉检测技术,因其具备快速、无损等优点被广泛应用于食品品质检测领域。电子鼻通常包括两部分:硬件部分——多个性能彼此重叠的气体传感器;软件部分——恰当的模式识别技术对采集信号的分析、处理。本文主要综述了近年来国内外电子鼻技术在肉类品质分析中的应用。首先阐述了电子鼻技术工作原理、数据处理方法,随后重点讨论了电子鼻技术在肉类新鲜度评定、肉与肉制品品质区分、肉类有害成分监测、肉类掺假检测等4个方面的应用进展,最后对电子鼻技术目前存在的问题及未来发展趋势进行了简要探讨。     

Preparation of guanidine group functionalized magnetic nanoparticles and the application in preconcentration and separation of acidic protein

Guanidine group (Gnd) functionalized magnetic nanoparticles (Fe3O4@SiO2@NH2-Gnd) were synthesized and characterized in this work for the first time. The characterization of Fe3O4@SiO2@ NH2-Gnd nanoparticles was demonstrated by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra, vibration sample magnetometer, and zeta potential analyzer. The novel multifunctional nanoparticles were served as a solid-phase extraction sorbent for easy isolation and preconcentration of acidic protein from aqueous solution only using a magnet. Bovine serum albumin (BSA) was selected as a model protein and the main experimental parameters influencing the adsorption and desorption efficiency were investigated and optimized. Under the optimum conditions, the particles reached saturated adsorption within 20 min and exhibited significant specific recognition for the acidic proteins. Fifteen fold enrichment efficiency was achieved and the detection limits was 45 ng x mL(-1) for BSA by capillary electrophoresis (CE). The practical application of the novel nanoparticles as a sorbent for the isolation and preconcentration of acidic proteins from basic proteins was demonstrated by effective separation and enrichment of bovine serum albumin from lysozyme and cytochrome C mixture, which was assayed by CE.     

阶梯坑施工顺序对基坑变形及结构受力影响

南京惠民大道综合改造工程为大型地下互通立交项目,因匝道与主线隧道交错导致深基坑施工过程中存在阶梯坑工况,阶梯坑开挖存在无支撑暴露时间长、变形控制难等特点.为寻求阶梯坑施工最优工序,采用ABAQUS软件对阶梯坑在3种不同工况下进行理论分析,得出阶梯坑在不同施工顺序下基坑的变形规律及已完成结构的受力情况.     

L波段小擦地角海杂波幅度统计特性研究

为了研究L波段小擦地角海杂波幅度统计特性及其在不同海洋参数条件下的差异,该文结合海杂波实测数据,选取适当的拟合优度检验准则,对比分析给出了不同波高和风向条件下Rayleigh, Weibull, Log-normal, K分布等经典统计分布模型,以及典型参数条件下Pareto分布在L波段小擦地角海杂波建模中的拟合效果,可为雷达目标检测中杂波模型的选择提供参考,提高海洋环境背景下目标检测的适应能力。