延长酱渣保存期的探讨

酱油生产过程中会产生大量酱渣，酱渣容易变质，通过试验研究导致酱渣变质的原因，找出了延长酱渣保存期的方法，对酱渣的再利用提供了有利的条件。     

固相萃取-气相色谱法测定桑葚等浆果中百菌清、腐霉利和联苯菊酯3种农药残留

目的建立固相萃取-气相色谱法测定桑葚等浆果中百菌清、腐霉利和联苯菊酯3种农药残留的分析方法。方法乙腈提取桑葚浆果样品中的3种农药,提取液经HLB固相萃取柱富集、净化,丙酮+环己烷(1:9,V:V)洗脱,洗脱液氮吹至近干,环己烷定容至1 mL,上气相色谱仪定量检测。结果百菌清、腐霉利和联苯菊酯在浓度为0.002～0.200μg/mL范围内线性关系良好;百菌清、腐霉利和联苯菊酯定量限分别为0.0002、0.0006、0.0006 mg/kg;方法加标回收率在85.8%～99.7%之间;精密度和重复性RSD均在10.0%以内。结论方法具有简便、准确、快速等特点,可以用于桑葚等浆果中的农药残留检测。     

黄芪渣中国拟青霉固体培养及发酵产物分析

以黄芪渣培养冬虫夏草菌——中国拟青霉,研究固体发酵条件及发酵产物成分含量变化。结果表明:固体发酵的温度为20℃,培养基含水量60%,pH自然,氧气充足,无需光照条件下适宜生长,发酵时间为45 d。虫草黄芪粉粗多糖含量为10.32%,比黄芪废弃物中粗多糖含量增加47%;甘露醇含量为2.38%,比黄芪废弃物中甘露醇含量提高11.5倍;水溶蛋白含量为1.72%,比黄芪废弃物高2.80倍。     

三聚氰胺在罗非鱼体内的残留和消除规律研究

以罗非鱼(Tilapia)为研究对象,通过在罗非鱼饲料中添加不同剂量三聚氰胺进行罗非鱼摄食生长试验,研究三聚氰胺在罗非鱼肝脏和肌肉中的残留和消除规律。实验结果表明:(1)罗非鱼连续饲喂含三聚氰胺的饲料50d,添加不同剂量的三聚氰胺对各组罗非鱼的平均体重增长无显著影响(P>0.05);(2)肝脏和肌肉中三聚氰胺的残留量随着各实验组饲料中添加量的增加呈显著递增趋势(P<0.05),低剂量组(1000、5000mg/kg)的肝脏和肌肉中的残留量在2～20mg/kg间,高剂量组(10000、50000mg/kg)的残留量均超过40mg/kg,各组中肝脏的残留量均显著高于肌肉(P<0.05)。停药5d后,罗非鱼的肝脏和肌肉中三聚氰胺的残留量均内显著下降,各实验组的三聚氰胺残留量均降至2.0mg/kg以下,此后则缓慢下降。各实验组中,肌肉的消除时间比肝脏的消除时间长。     

黄瓜和土壤中吡唑醚菌酯和霜脲氰同步检测及其降解分析

采用QuEChERS-液相色谱-串联质谱法,建立黄瓜及土壤中吡唑醚菌酯和霜脲氰同步检测方法,研究吡唑醚菌酯·霜脲氰水分散粒剂在黄瓜和土壤中的残留变化及消解动态,旨在评估联合农药的安全性。样品经乙腈提取,N-丙基乙二胺吸附剂和十八烷基键合硅胶吸附剂净化,质谱多反应监测模式扫描。在50～800?μg/L之间具有良好的线性关系,r值均大于0.996?1,3?个质量浓度添加水平下2?种农药在黄瓜和土壤中的平均回收率为70.45%～107.08%,定量限均为0.050?mg/kg。两年三地的田间实验消解动态表明：以1.5?倍高推荐剂量下,吡唑醚菌酯和霜脲氰分别于黄瓜上施药1、7?d后,土壤上施药7、1?d后残留量小于定量限;当该制剂以推荐剂量在黄瓜上施药3?次,施药间隔7?d时,吡唑醚菌酯和霜脲氰在黄瓜中的最高残留量分别为0.090?mg/kg和0.060?mg/kg,远低于我国规定的最大残留限量0.5?mg/kg,推荐采收安全间隔期为3?d。     

燃糠醛渣循环流化床锅炉的设计

本文介绍了20 t/h燃糠醛渣循环流化床锅炉的结构、设计特点及锅炉运行需注意的问题。     

Ni doped carbons for hydrogen production by catalytic methane decomposition

Ni doped carbons were prepared from raw coal and direct coal liquefaction residue (CLR) by KOH activation with addition of Ni(NO₃)₂, and used for catalytic methane decomposition (CMD) to produce hydrogen. The catalytic activity of the Ni doped carbon for CMD was compared with those of metal catalysts (Ni/SiO₂ and Ni/Al₂O₃), coal- and CLR-based carbons, and Ni-carbon catalysts prepared by traditional impregnation and precipitation methods. The results show that the Ni doped carbon has higher and more stable activity than the metal and carbon catalysts at 850 °C. The preparation method for Ni doped carbons can make full use of the reducibility of the carbon composition and simplify the traditional synthesis process. The Ni content and the morphology of carbon deposits produced during CMD have a great effect on the catalytic activity of the Ni doped carbon.     

15%腐霉利烟剂在保护地番茄及土壤中的消解动态与残留量

为评价腐霉利在保护地番茄上使用的安全性,建立其使用规范,2013年在6地进行了15%腐霉利烟剂在番茄和土壤中的残留试验。样品采用乙腈提取,固相萃取柱净化,气相色谱电子捕获检测器进行检测,外标法定量。结果表明:腐霉利在番茄和土壤中的半衰期分别为1.9~3.7 d和1.4~2.7 d。番茄及土壤中腐霉利残留量均低于2 mg/kg。     

Preparation of semirigid polyurethane foam with liquefied bamboo residues

Bamboo residues were liquefied by using a solvent mixture consisting of polyethylene glycol 400 and crude glycerol (4/1, w/w) with 98% sulfuric acid as catalyst at 160°C for 120 min. The liquefied bamboo had hydroxyl values from 178 to 200 mg KOH/g and viscosities from 507 to 2201 mPa S. The obtained bamboo‐based polyols were reacted with various amounts of polyaryl polymethylene isocyanate (PAPI), using distilled water as blowing agent, silicone as surfactant, and triethylenediamine and dibutyltine dilaurate as cocatalyst to produce semirigid polyurethane (PU) foams. The [NCO]/[OH] ratio was found to be an important factor to control the mechanical properties of PU foams. At a fixed [NCO]/[OH] ratio, both density and compressive strength of PU foams decreased with the increase of bamboo content. The microstructure of PU foams indicates that [NCO]/[OH] ratios are important for cell formation and chemical reactions. The uniformity and cell structure of the foams are comparable to their corresponding compressive strengths. Moreover, the thermogravimetry analysis showed that all the semirigid PU foams had approximately the same degradation temperature of about 250 to 440°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

高效液相色谱-质谱技术在食品安全检测中的应用

本文综述高效液相色谱及其与紫外、质谱检测器在食品安全检测中的应用。详述食品中三聚氰胺、苏丹红、食品添加剂、农药残留量、抗生素药物残留量、毒素的检测等的检测技术。对于保证食品质量、维护人民健康安全有着重要意义。