Application of Dispersed Particle Gel to Inhibit Surfactant Adsorption on Sand

This article highlights an efficient and cost-effective additive-dispersed particle gel (DPG) to reduce surfactant adsorption on sand. Indoor experiments were conducted to study the effect of DPG on static adsorption and dynamic adsorption of the surfactant. The static adsorption data were evaluated using different isotherm models and the Redlich–Peterson isotherm matched the best. Results showed a significant inhibition of surfactant adsorption in the presence of DPG. The dynamic adsorption of SDS on sand decreased to 0.78, 0.68 and 0.61 mg/g compared with original value of 1.17 mg/g by adding 0.1, 0.2 and 0.3 wt% DPG particles, respectively. This study suggests that DPG can inhibit the adsorption of surfactant on sand effectively.     

含马钱子中成药的研究概况回顾性分析

回顾分析近30年常用含马钱子中成药的质量控制、药理及临床研究,认为此类药的研究还不够深入,有待对其进行系统规范的深入研究。     

固相萃取-超高效液相色谱法测定兵器工业生产废水中14种硝基酚类物质残留浓度

为了满足环境水样中痕量硝基酚类污染物检测的要求,在硝基酚快速检测中应用Bond Elut Plexa新型固相萃取柱,建立了快速同时测定兵器工业生产环境水样中三硝基苯酚(苦味酸PA)、三硝基间苯二酚(斯蒂酚酸TNR)和三硝基均苯三酚(TNPG)等14种硝基酚的超高效液相色谱分析方法。水样样品采用固相萃取柱净化,上样5.0 m L,并最终用3.0 m L四氢呋喃洗脱,洗脱液浓缩转溶剂后采用色谱分析。选择全氟苯基色谱柱,以乙腈和乙酸铵及0.1%甲酸作为流动相,梯度洗脱,检测波长为220 nm,在优化的固相萃取前处理和液相色谱分离分析条件下,净化效果满足要求。14种硝基酚类化合物在22 min内实现完全基线分离,在0.1~20 mg/L范围内线性良好,相关系数为0.997 3~0.998 7;检出限为0.02~0.04 mg/L,回收率为82.5%~104.8%,相对标准偏差3.2%~5.7%.本方法已成功应用于生产环境水中实际样品的分析。     

Concept for automated computer-aided identification and evaluation of potentially non-compliant food products traded via electronic commerce

The online marketplace for food products is continually expanding and all types of food and beverages can now be purchased over the internet. It is primarily the responsibility of the food business operator to ensure compliance with food safety law. However, the competent authorities are tasked with controlling the e-food sector as part of their regulatory duties to protect consumer health and to prevent fraud, regardless of the sales channel being used. For this purpose, a new software prototype concept was developed that automatically identifies and evaluates potentially non-compliant e-food products. The prototype was developed using a modular architecture comprising a research tool, an image analysis tool, and a monitoring tool. User-defined thresholds are applied to assess the reliability of the retrieved data. Results that are not deemed reliable enough can be reworked using a computer-aided evaluation interface. The research tool utilizes both internet search engines and customized search algorithms. A multi-stage filtering process is performed to limit the sites according to defined criteria (e.g. food product merchants only). The data acquisition module stores all matching data from webpages for later analysis and preservation of evidence. In another module, automatic recognition of a site's legal notice (impressum) is carried out for the respective vendor within whose online shop a potentially non-compliant food product is being offered. The image analysis tool performs logo recognition to enrich the text-based information of websites, thus providing additional visual information. The monitoring tool performs regular automated monitoring of e-food vendors, products and ingredients. The proof of principle of the prototype was achieved by conducting a web search for hazardous food products containing synephrine and caffeine. In total, 1242 product offerings on the internet for suspicious food products were identified among the 8683 search results. The software prototype has potential to enhance consumer protection and food safety with respect to e-foods.     

Stable auto-tuning of hybrid adaptive fuzzy/neural controllers for nonlinear systems

In direct adaptive control, the adaptation mechanism attempts to adjust a parameterized nonlinear controller to approximate an ideal controller. In the indirect case, however, we approximate parts of the plant dynamics that are used by a feedback controller to cancel the system nonlinearities. In both cases, “approximators” such as linear mappings, polynomials, fuzzy systems, or neural networks can be used as either the parameterized nonlinear controller or identifier model. In this paper, we present an algorithm to tune the adaptation gain for a gradient-based hybrid update law used for a class of nonlinear continuous-time systems in both direct and indirect cases. In our proposed algorithm, the adaptation gain is obtained by minimizing the instantaneous control energy. Finally, we will demonstrate the performance of the algorithm via a wing rock regulation example.     

我国与主要贸易国家间猪肉中农药残留限量对比分析

掌握不同国家、地区猪肉中农药最大残留限量（Maximum Residue Limits，MRL）要求现状，分析其差异性，以便降低猪肉贸易风险。收集我国和主要贸易国家，联合国粮农组织食品法典委员会（Codex Alimentarius Commission，CAC）、澳大利亚、美国、日本、新西兰、欧盟现行的猪肉农药MRLs标准和技术法规进行对比分析。由于各国饮食习惯、膳食结构不同，我国与主要贸易国家之间存在农药MRL差异，主要表现在：部分农药残留物的定义中所包含的农药转化物、代谢物、反应产物等的不同；农药最大残留限量指标数量和品种的不同，其中我国与欧盟、日本和澳大利亚等国在指标数量上差异较大；相同农药残留限量指标的宽严程度不同，个别指标差异较大。我国应继续加强国际间猪肉农药残留限量标准制定交流，进一步完善我国猪肉农药残留限量标准体系。     

通过式固相萃取净化-超高效液相色谱-串联质谱法快速测定禽肉中利巴韦林的残留量

建立了通过式固相萃取净化-超高效液相色谱-串联质谱法快速测定禽肉中利巴韦林残留量的方法。样品在37 ℃经酸性磷酸酯酶酶解,乙腈提取,EMR-Lipid固相萃取柱净化,以乙腈和0.1%甲酸水（含5 mmol/L甲酸铵）为流动相,经过BEH Z-HILIC色谱柱（100 mm×2.1 mm,1.7 μm）分离,经串联质谱仪,在电喷雾正离子模式下以多反应监测（MRM）模式测定,同位素内标法定量。对前处理条件、液相条件和质谱参数进行了系统的考察。该方法在0.05~5 μg/L质量浓度范围内线性关系良好,定量限（LOQ）为2.0 μg/kg。在2.0、4.0、20 μg/kg添加水平下,回收率为94.5%~112.0%,相对标准偏差（n=6）为1.4%~3.2%。该方法相比标准方法前处理简单、快速,适用于禽肉中利巴韦林残留的批量分析。     

我国2016~2019年炒货食品及坚果制品质量安全状况及风险分析

目的 分析2016~2019年我国坚果炒货食品的安全形势。方法 结合2016~2019年国家和各省市场监督管理局公开发布的食品监督抽检信息, 对其不合格项目等信息进行分析。结果 炒货食品及坚果制品的主要不合格项目为品质指标(过氧化值、酸价等)、微生物指标(霉菌、大肠菌群等)和食品添加剂(二氧化硫、糖精钠等),主要不合格种类为花生、瓜子和豆类。酸价和过氧化值主要不合格原因为炒货原料质量不达标、生产过程控制不严、储存条件不当、包装密封性不好; 霉菌和大肠菌群主要不合格原因为原料、包装材料、生产过程中人员卫生、器具等生产设备、环境的污染 、熟制过程中杀菌不彻底; 二氧化硫和糖精钠主要不合格原因为超范围使用食品添加剂和添加量控制不当。结论 建议监管部门完善标准体系、加强原料监管和生产过程控制、严格食品添加剂管理、引导企业建立食品安全可追溯体系和加强企业食品安全意识和责任意识。     

原子吸收光谱法测定四季感冒片铬含量

目的测定市场上四季感冒片铬含量,为制定四季感冒片标准提供参考数据。方法采用硝酸浸泡过夜,微波消解,石墨炉原子吸收光谱法测定。结果线性相关系数为0.9981,加样回收率96.9%,检出限0.41 ng/mL,重复性RSD为1.6%(n=6)。结论此法可用于四季感冒片质量控制,结果表明,市场上四季感冒片铬含量潜在风险较低。     

超声辅助提取-氢化物原子荧光光谱法测定香辛料中的铅

建立了一种操作简单、快速、高灵敏度、高提取效率的超声辅助提取-氢化物发生-原子荧光光谱法测定香辛料中铅的分析方法。考察了提取液的酸度、超声温度和时间对提取效率的影响,最终确定1.5%的硝酸为提取溶剂,超声时间和温度分别为60 min,40℃。考察了载流酸度、铁氰化钾浓度对铅测定时荧光值和线性系数的影响。实验表明铅含量在0~20μg/L范围内线性关系良好,线性相关系数大于0.999,检出限为2.6μg/kg,相对标准偏差为1.59%~3.52%,加标回收率为98.3%~108.3%,适用于香辛料中铅含量的检测。