固相萃取离子色谱法快速测定烟草中钾、钠、钙、镁和氨的研究

采用带固相萃取净化功能的样品萃取瓶超声萃取烟草样品,样品萃取液用石墨化炭黑球固相萃取净化。然后以IonPacCS12A阳离子交换色谱柱(3 ′ 150 mm,5 μm)为固定相,30 mM甲基磺酸为流动相,淋洗液流速1.0 mL/min,K+、Na+、Mg2+、Ca2+、和NH4+ 5种阳离子在6.0 min内可达到完全分离。采用自主设计的样品萃取瓶,可不经样品转移就完成样品的萃取、净化和过滤。和常规方法相比,操作流程得到简化,效率大幅度提高,灵敏度和回收率高、精密度好。为基因编辑素材钾、钠、钙、镁和氨的快速测定提供了高通量分析方法。     

超高效液相色谱串联质谱非衍生化法测定土壤中草甘膦及其代谢物氨甲基膦酸含量

为了建立土壤中草甘膦(Glyphosate）及其主要代谢物氨甲基膦酸(AMPA)残留的定量分析方法,采用固相萃取结合液相色谱串联质谱技术,样品以磷酸钠和柠檬酸三钠混合溶液提取,经固相萃取柱净化,采用正向亲水性液相色谱柱(Hilic)梯度洗脱,通过质谱的多反应监测(MRM)负离子模式扫描进行测定,外标法定量。结果表明:草甘膦、氨甲基膦酸的线性范围为0.02~0.2 μg/mL,相关系数(R²)分别为0.9995、0.9998,检出限分别为0.5 μg/kg和0.6 μg/kg,定量限分别为1.6 μg/kg和2.0 μg/kg;3个加标水平草甘膦的回收率在79.67%~96.17%之间,AMPA回收率在77.83%~99.47%之间,RSD值分别为3.95%~7.49%、1.96%~3.89%。与传统的柱前衍生方法相比,具有前处理简单、检出限低、灵敏度高的优点,完全可以适用于土壤中草甘膦的分析。     

车-液耦合响应下液罐车稳定性控制仿真

为了提高液罐车行驶安全性、减少液罐车侧翻、失稳所带来的危害,对于液罐车在转向或换道时车-液耦合动态响应对整车稳定性的影响进行了研究。联合液体纳维斯托克斯和流动控制方程,应用计算流体动力学软件ANSYS/Fluent建立并求解液体晃动模型,通过结合液体晃动模型和三自由度液罐车刚体模型获得液罐车车-液耦合动力学模型,分析有无控制策略情况下,液体晃动对液罐车横向稳定性的影响。仿真结果表明:提出的模糊差动制动控制策略能够有效提高车辆抗侧翻能力,减少罐车运输过程中交通事故的发生,对液罐车运输有指导意义。     

Effects of germination and kilning on the phenolic compounds and nutritional properties of quinoa (Chenopodium quinoa) and kiwicha (Amaranthus caudatus)

Quinoa (Chenopodium quinoa) and kiwicha (Amaranthus caudatus) are nutritious pseudocereals that originate from the Andean region. The aim of this research was to study the effect of germination and the subsequent kilning on the phenolic compounds and proximate composition in selected Peruvian varieties of quinoa (“Chullpi”) and kiwicha (“Oscar Blanco”). The germination process was carried out for 24, 48 and 72 h at 22 °C, and the kilning was performed with samples germinated for 72 h by drying the seeds at 90 °C for 5 min. Both processes increased the protein content of the samples. However, lipid content was reduced during germination. On the other hand, germination and kilning clearly increased the concentration of total phenolic compounds in both quinoa and kiwicha. Germination for 72 h either with or without kilning process resulted in a significant (p < 0.05) increase in the total content of phenolics compared to untreated materials, which was especially due to coumaric acid and a kaempferol tri-glycoside in quinoa and caffeoylquinic acid in kiwicha. Based on the results, germination and kilning may improve the nutritional quality of the Andean grains, encouraging the usage of the processed grains as ingredients in functional products for people with special gluten-free or vegetarian diets.     

Recent progress in analytical method development to ensure the safety of gluten-free foods for celiac disease patients

As laid down by the Codex Alimentarius, products bearing a gluten-free label must not contain gluten levels above 20 mg/kg to be safe for consumption by celiac disease patients. Analytical methods to detect gluten from wheat, rye and barley need to be sufficiently sensitive, specific, suitable for routine analyses and validated by collaborative studies. With continuous progress in the field of gluten analysis, the aim of this paper is to provide an up-to-date overview of legislation regarding gluten-free products worldwide, as well as immunochemical, proteomics-based, genomics-based and other methods designed to analyse gluten traces. While ELISA test kits and PCR are still most widely used in quality control, liquid chromatography tandem mass spectrometry (LC-MS/MS) is gaining more and more importance by providing unprecedented insights into gluten. Several other methods such as immunosensors, other sensors and microarrays are being developed. The pro's and con's of the different methods are discussed as well as the remaining challenges, including the need for improved extraction procedures, comprehensive reference materials and independent reference methods.     

5种杀虫剂超低容量液剂对玉米田草地贪夜蛾的防治效果

草地贪夜蛾是新入侵我国的迁飞性重大害虫,为害玉米的心叶、生长点及雄穗等,能引起严重的损伤、烂心、授粉不良等,导致玉米减产甚至绝产。本文评价了5种杀虫剂超低容量液剂通过低容量喷雾对玉米田草地贪夜蛾的防治效果。结果表明,在相同的原药成本下,6%甲维·茚虫威超低容量液剂和1%甲氨基阿维菌素苯甲酸盐超低容量液剂具有优异的保叶效果和杀虫效果,5%氯虫苯甲酰胺超低容量液剂在较低的用量下(有效用量1 g/667m~2)具有良好的保叶和杀虫效果,3%呋虫胺超低容量液剂对草地贪夜蛾幼虫基本无效,但有一定的保叶效果。     

固相萃取-高效液相色谱串联质谱法测定油菜薹中反式维生素K1含量

为准确测定反式维生素K1的含量，建立了基于固相萃取-高效液相色谱串联质谱的甘蓝型油菜（Brassica napus L.）菜薹反式维生素K1高灵敏检测技术。样品经正己烷提取、中性氧化铝柱净化后，用C30反相色谱柱，以甲醇 （含0.025%甲酸+2.5 mmol/L甲酸铵）为流动相，采用选择反应监测（selected reaction monitoring, SRM）模式进行定量分析，20 min内可实现顺反异构体色谱分离。方法学考察结果显示，反式维生素K1在范围内线性关系良好，相关系数为0.9985。该方法检出限为0.29 μg/kg，定量限为0.95 μg/kg。回收率为87.5%～117.6%，精密度（RSD）在0.72% ～9.59%之间。利用该方法对油菜薹和反式维生素K1含量高的3种蔬菜进行分析，发现油菜薹中反式维生素K1含量为340.08 μg/100g，高于小白菜（B. rapa spp. chinensis，260.93 μg/100g）、西兰花（B. oleracea var. Italic Planch， 167.65 μg/100g）和结球甘蓝（B. oleracea var. capitata，151.11 μg/100g）。本文建立的蔬菜中反式维生素K1准确定量分析方法操作简单、灵敏度高、结果准确。同时比较发现油菜薹是一种富含维生素K1的蔬菜。      

油菜薹和蕾中硫代葡萄糖苷组分及含量分析

采用超高效液相色谱（UPLC）法，对30 个油菜品种薹和蕾中硫代葡萄糖苷（glucosinolate，简称硫苷）的组分及含量进行测定。结果表明：30 个油菜品种的总硫苷含量变异范围较大，在21.67～119.29 μmol·g^-1 之间；大多数油菜品种蕾中的硫苷含量高于薹，蕾中硫苷含量均值为37.26 μmol·g^-1，薹中为28.06 μmol·g^-1；薹和蕾中的硫苷组分相似，均以4- 戊烯基硫苷和2- 羟基-3- 丁烯基硫苷为主要成分，两者在薹和蕾中的含量分别占总硫苷含量的46.24%、28.52% 和45.19%、29.13%。进一步分析高、中、低硫苷含量油菜品种的硫苷组分及含量，结果表明油菜不同品种间硫苷含量的差异主要是由4- 戊烯基硫苷引起的。     

长期施用沼肥对设施菜田土壤养分和盐分累积量的影响

为研究规模养猪场沼液沼渣在农田施用对土壤养分及盐分含量累积的影响,以安康市某养猪场农业园区施用沼液设施菜田土壤为研究对象,以当地常规施用化肥设施菜田为对照,定点采集施用沼肥区和对照区0 a、1 a、3 a、5 a和7 a的设施菜地土壤,分别测定土壤中碱解氮、有效磷、速效钾、有机质、全铜、全锌质量分数及电导率和pH。结果表明,随着沼液沼渣施用年限的增加,土壤中碱解氮、有效磷、速效钾、有机质、全铜、全锌质量分数和电导率均相应增加,7 a后分别达96.1 mg/kg、91.5 mg/kg、73.7 mg/kg、11.9 g/kg、118.5 mg/kg、263.4 mg/kg和0.366 mS/cm,分别是未施用沼液沼渣土壤中各成分含量的3.4倍、1.5倍、3.3倍、1.3倍、3.9倍、1.88倍和4.74倍,说明施用沼液沼渣能有效增加土壤养分含量,同时土壤养分和盐分快速累积,对土壤环境带来较大的污染风险。     

菜籽油裂解燃料离子液体催化酯化反应降酸工艺的研究

为了降低裂解燃料酸值,增加燃料的稳定性能,将吡啶丁烷磺酸硫酸氢盐应用于菜籽油裂解燃料的酯化反应。考察了催化剂用量、反应时间和反应温度等对酸值的影响,并在最佳优化条件下考察了裂解燃料成品的理化性质。结果表明:吡啶丁烷磺酸硫酸氢盐对催化酯化反应具有很高的催化活性。优化工艺条件为:催化剂用量1.2%、反应温度75℃、反应时间70 min,在此工艺条件下,酸值降低到1.0 mgKOH/g以下。