Original diols from sunflower and ricin oils: Synthesis,characterization, and use as polyurethane building blocks

A series of novel fatty acid‐based diols were designed and synthesized from sunflower and ricin oils using optimized chemical reactions and purifications. These diols were categorized in two different types: (i) fatty acid‐based monoester containing diols (FAmE‐1 to FAmE‐6) and (ii) fatty acid‐based diester containing diols (FAdE‐1 to FAdE‐8). Their synthesis involved a series of reactions such as transesterification, epoxidation, ring opening of epoxide, and thiol‐ene additions. Analyses of these new fatty acid‐based diols were performed by HPLC/GC and NMR spectroscopy. The latter were then demonstrated as polyurethane (PU) precursors in the bulk polymerization with isophorone diisocyanate in the presence of dibutyl tin dilaurate as a catalyst. The effects of the diol nature and purity on the PU synthesis and properties were investigated. The structural characterization of the different PUs was carried out by means of FTIR, ¹H NMR, and ¹H DOSY NMR spectroscopy. The thermomechanical and rheological properties of these new PUs were found dependent on the chemical structure and purity of the diol building block. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

固相萃取/高效液相色谱-串联质谱法测定植物性食品中链霉素与双氢链霉素

建立了植物性食品(苹果、芹菜、甜椒、干扁豆)中链霉素(Streptomycin,STR)和双氢链霉素(Dihydrostreptomycin,DHS)的高效液相色谱-串联质谱(HPLC-MS/MS)检测方法。样品经磷酸盐缓冲溶液提取,借助WCX固相萃取柱富集净化后,采用Atlantis Hilic Silica亲水作用色谱柱(100 mm×3.0 mm,3μm)分离,乙腈-0.1 mol/L甲酸铵和0.1%甲酸溶液等度洗脱,以电喷雾电离串联质谱多反应监测(MRM)正离子模式进行检测,外标法定量。结果显示,链霉素和双氢链霉素在10～120μg/L质量浓度范围内线性良好,相关系数(r)均大于0.999,定量下限均为125μg/kg。本底空白的4种样品基质在3个添加水平(125、250、500μg/kg)下的平均回收率为83.6%～101%,相对标准偏差为2.3%～7.8%。该方法无需使用对LC-MS联用仪造成污染的离子对试剂,且方法操作简便、快速、可靠、稳定,能满足大部分植物性食品中链霉素和双氢链霉素的检测需要。     

土壤及蔬菜中微量汞的同位素稀释电感耦合等离子体质谱测定

建立了微波消解电感耦合等离子体质谱同位素稀释(ID/ICP-MS)测定微量汞的方法。考察了仪器参数及测量条件对汞同位素比值RHg(202Hg/200Hg)测量的影响,根据同位素比值测量误差的传递因子优化了富集同位素稀释剂(202Hg98%)的加入量,并以铊同位素比值(205Tl/203Tl)作为RHg(202Hg/200Hg)测量时发生质量歧视效应的校正因子;通过反同位素稀释法标定了富集汞同位素稀释剂的浓度。利用所建立的ID/ICP-MS方法测定了杨树叶(GBW07604)和湖积物(GBW07423)2种标准参考物中汞的含量,回收率分别为112%和100%。该方法具有准确度高、精密度好等优点,且样品前处理简便,适用于土壤及蔬菜等样品中微量及痕量汞的准确测定。     

镉污染对蔬菜镉吸收和积累的影响

通过水培和土培试验研究了外源镉添加对3种蔬菜镉吸收和积累的影响。结果表明,随着外源镉添加质量浓度的提高,蔬菜可食用部位镉含量随着增加,蔬菜可食用部位镉含量与环境介质中外源镉添加质量浓度呈现出显著的线性相关。3种蔬菜中,芹菜对镉的吸收能力最强,其次为小白菜,而辣椒果实对镉的吸收能力最弱,仅为小白菜的25％。（以小白菜、芹菜、辣椒）中镉元素的最大允许量为限值,根据相关回归方程计算得到了溶液中镉的临界质量浓度值分别为0．06,0．086,0．11mg／L,而土壤中镉的临界质量分数分别为0．68、0．57、0．60mg／kg。     

来自天然植物油的聚合物

植物油是由脂肪酸和甘油化合而成的天然高分子,它广泛分布于自然界中.植物油是一种可再生的生物资源,出于环境的考虑,已经用于代替燃料油制备各种聚合物,并已广泛用于肥皂、油漆、油墨、橡胶、制革、纺织、蜡烛、润滑油、合成树脂、化妆品及医药等行业. 植物油可来自大豆、花生、棕榈油、蓖麻等植物,它们的主要成分是甘油三酸酯.本文将讨论甘油三酸酯的结构和基于它的聚合物,以及不同天然植物油合成的聚合物,它们的性质及应用.     

高效液相色谱法测定蔬菜中19种氨基甲酸酯类农药的残留量

均质后的蔬菜样品用乙腈提取,SPE-NH2固相萃取小柱净化,采用高效液相色谱法测定净化液中19种氨基甲酸酯类农药的残留量。以PICKERING Carbamate Analysis-C8色谱柱为分离柱,用甲醇和水以不同比例混合的溶液为流动相进行梯度洗脱,在线柱后衍生后,用荧光检测器进行测定。抗蚜威的激发波长为339nm,发射波长为392nm,其余18种氨基甲酸酯类农药的激发波长339nm,发射波长为445nm。19种氨基甲酸酯类农药的质量浓度在一定范围内与其对应的峰面积呈线性关系,检出限(3S/N)为0.002~0.014mg·kg^-1。以空白花菜样品为基体进行加标回收试验,所得回收率为47.7%~110%,测定值的相对标准偏差(n=6)为1.0%~12%。     

QuEChERS提取-超高效液相色谱-串联质谱法测定蔬菜中氨基甲酸酯类农药的残留量

将蔬菜样品粉碎匀浆后于-20℃保存备用。取此样品10.00g与含1.3%(体积分数)甲酸溶液的乙腈10mL充分混匀后超声提取20min,加入无水硫酸钠8.2g作为脱水剂,氯化钠3.0g作为盐析剂,混合后离心5 min。取出上清液并保留。对留下的样品按上述方法重复提取1次。将2次所得上清液合并,并从中分取2.0mL溶液,加入吸附剂N-丙基乙二胺(PSA)0.4g,C180.25g和石墨化碳黑(GCB)8.2mg,涡旋振荡2min进行净化处理,随即离心2min,取上清液经0.22μm滤膜过滤。取滤液,按超高效液相色谱-串联质谱法测定其中6种氨基甲酸酯类农药的残留量。用Agilent Poroshell 120EC-C18色谱柱为固定相,进样量为5μL。用由不同比例的(A)20mmol·L^-1乙酸铵溶液(每升中含乙酸1mL)和(B)乙腈组成混合液作为流动相进行梯度洗脱。串联质谱分析选择电喷雾离子源和多反应监测模式。所测定的6种氨基甲酸酯类农药的工作曲线的线性范围均为0.200~100μg·L^-1,并测得其检出限(3S/N)为0.08~0.38μg·kg^-1。按标准加入法进行回收试验,测得回收率为81.0%~111%,测定值的相对标准偏差(n=6)为2.8%~4.9%。     

高光谱分析叶菜对颗粒物污染的响应特征规律

大气中的颗粒物不仅影响人类生活,还影响植物的光合作用、生长发育和产量品质。实现了颗粒物污染环境的人工模拟,并对采收期的小白菜、生菜、小油菜三种叶菜进行颗粒物作用试验,获取叶片的光合生理信息和高光谱数据,基于高光谱技术和植物表型分析叶菜对颗粒物的响应机理,研究叶菜的光合特性和光谱特征对颗粒物污染的响应情况。结果表明：以颗粒物作为唯一差别条件下,三种叶菜叶片的高光谱曲线整体趋势相同,在可见光波段内试验组反射率增加最大,红边位置发生蓝移,小油菜对颗粒物的作用最敏感,小白菜吸附颗粒物的能力最强。分别比较三种叶菜的净光合速率与叶片原始光谱、一阶导数光谱的相关性,利用相关分析法提取三种叶菜的敏感波段,用原始光谱、FD、MSC和相关分析法提取特征波长;比较10个高光谱特征参数及4个植被指数与净光合速率的相关系数,选出敏感光谱特征参数和植被指数,即生菜的Dr,SDr,SDr/SDb和SDr/Sdy,小白菜的SDr,Dy,NIRRP,(SDr-SDy)/(SDr+SDy)以及小油菜的λr,SDy,(SDr-SDy)/(SDr+SDy)。用ln对数运算、多项式函数以及几种组合方法建立三种叶菜叶片的净光合速率定量反演模型,其中,预处理方法采用SG,FD,SD和MSC,建模方法采用CLS,PLS,PCR和SMLR。以相关系数为模型评价指标,最终确定FD+SG+PLS方法是建立生菜和小白菜净光合速率反演模型的最优方法,FD+SG+MSC+SMLR方法是建立小油菜净光合速率反演模型的最优方法。所建模型可为今后颗粒物污染环境下的模型修正提供参考,具有实用性。研究结果为利用高光谱技术研究叶菜类蔬菜在颗粒物污染环境下的诊断与分析提供理论依据,为设施农业蔬菜的病害预警、生理信息监测、设施环境的净化和管控提供新思路。     

Recent Discoveries in the Field of Lipid Bio-Based Ingredients for Meat Processing

Current culture and pace of lifestyle, together with consumer demand for ready-to-eat foods, has influenced the food industry, particularly the meat sector. However, due to the important role that diet plays in human health, consumers demand safe and healthy food products. As a consequence, even foods that meet expectations for convenience and organoleptic properties must also meet expectations from a nutritional standpoint. One of the main nutritionally negative aspects of meat products is the content and composition of fat. In this sense, the meat industry has spent decades researching the best strategies for the reformulation of traditional products, without having a negative impact in technological processes or in the sensory acceptance of the final product. However, the enormous variety of meat products as well as industrial and culinary processes means that a single strategy cannot be established, despite the large volume of work carried out in this regard. Therefore, taking all the components of this complex situation into account and utilizing the large amount of scientific information that is available, this review aims to comprehensively analyze recent advances in the use of lipid bio-based materials to reformulate meat products, as well as their nutritional, technological, and sensorial implications.     

微波消解/ICP-MS同时测定粮食、蔬菜中的11种重金属元素

建立了微波消解/电感耦合等离子体质谱法同时测定粮食和蔬菜中11种重金属元素(Cu、Mn、Cr、Pb、Cd、Ni、Sb、Hg、Co、Ag、As)的方法,优化了微波消解条件和仪器测定条件,采用HNO_3-HF-H_2O_2和HNO_3-H_2O_2两种混酸体系,将样品进行完全消解。结果显示,11种金属元素的线性系数不小于0.999 5,方法的检出限为0.001~10.00μg/L,测定的相对标准偏差(RSD,n=5)不大于5.0%。该方法具有快速、简便、灵敏度高、稳定性好、准确度高等优点。