毛细管流动色谱法研究丙烯在HZSM-5上的聚合作用

用毛细管流动色谱法分析丙烯在HZSM-5上聚合反应尾气,将此法与气相色谱-质谱联用技术相结合,对各反应产物分别定性,此法即可一次完成丙烯聚合反应产物的完全分离和定量。随着反应温度升高,尾气中芳构化产物增加,C_(4-6)链烃含量下降;丙烯通过齐聚物环化脱氢进行芳构化。     

毛细管气相色谱法测定食用油中15种反式脂肪酸的含量

提出了毛细管气相色谱法测定橄榄油、芝麻油和花生油中的15种反式脂肪酸。样品用异辛烷溶解,与2mol·L-1氢氧化钾的甲醇溶液进行酯化反应,生成的脂肪酸甲酯经强极性聚二氰丙基硅氧烷毛细管气相色谱柱SP-2560分离,用氢火焰离子化检测器检定。在优化的试验条件下,15种反式脂肪酸甲酯的质量浓度在一定范围内与其峰面积呈线性关系,方法的检出限(3S/N)和测定下限(10S/N)分别为0.012%(以脂肪计)和0.024%(以脂肪计)。对空白样品进行加标回收试验,回收率在86.6%~109%之间,测定值的相对标准偏差(n=10)在2.0%~4.2%之间。方法用于分析市售橄榄油、芝麻油和花生油中的15种反式脂肪酸,结果与标准方法的测定值相符。     

毛细管气相色谱法分析顺酐液相催化加氢反应产物

报道用毛细管气相色谱法分析顺酐液相催化加氢反应产物。使用交联SE-52石英毛细管柱，实现了顺酐等10种组分的分离，获得满意结果。     

毛细管气相色谱法测定深海鱼油中的EPA和DHA含量

用氢氧化钾－甲醇酯化法将深海鱼油中的脂肪酸快速、有效地转化成脂肪酸甲酯,然后进行毛细管气相色谱法测定,以二十二碳饱和脂肪酸甲酯为内标物,建立了5,8,11,14,17－二十碳五烯酸（EPA）和4,7,10,13,16,19－二十二碳六烯酸（DHA）的定量分析方法,并用于实际样品分析。该方法对EPA和DHA定量分析的相对标准偏差分别为4．6％和5．0％,回收率分别为99．7％和99．4％。     

用2D Micro-HPLC/MS分析六种蛋白质混合物的胰蛋白酶解多肽产物

采用2D Micro-HPLC系统,用MS对六种蛋白质的胰蛋白酶解多肽产物进行了分析,实现了蛋白质的高灵敏度、高分离度的检测。结合离子交换色谱法和反相毛细管色谱法,利用六个捕集柱和脱盐系统,可对各种分离条件进行优化。因此,可以实现对多种痕量酶解多肽的分离检测。该系统是痕量蛋白质和未知蛋白质检测的有力工具,结合高性能质谱仪,可以达到非常高的灵敏度。     

快速毛细管气相色谱分析白酒中的香味成分

本文建立了快速毛细管气相色谱法,在10 min内分离了白酒中的香味成分,并对其中的醇、醛、酸、酯进行定性分析,对主要呈味成分己酸乙酯进行定量分析,方法重复性好,回收率较高。与常规毛细管色谱法相比,快速毛细管气相色谱法有效地缩短了分析时间,提高了白酒的分析效率。     

毛细管气相色谱法检测果蔬中的丙线磷

对高速匀浆、超声波与振荡器3种提取效果进行了比较,表明高速匀浆法高效、节约,用毛细管气相色谱法氮磷检测器测定果蔬中的丙线磷,回收率为87.6%~99.5%,变异系数为1.30%~5.15%。     

酸枣仁油中脂肪酸的色谱分析

酸枣仁含油高达31.8％,但对酸枣仁油组成的分析未见报道。本文首次用毛细管气相色谱法对酸枣仁油中的脂肪酸进行了定性和定量分析。     

中国梨木虱分泌物中氨基酸的分离与分析

利用离子交换色谱法分离了中国梨木虱分泌物中的氨基酸;利用毛细管气相色谱法对梨木虱分泌物中氨基酸的三氯乙酰了酯衍生物进行了分析。用标准样对照定性,内标法定量。分泌物中共检出13种氨基酸。     

海洋石油降解细菌对石油烃降解效果的气相色谱法分析

用毛细管气相色谱法分析评价海洋石油降解细菌对石油烃的降解效果,结果表明,毛细管气相色谱法能够测定出石油降解细菌对石油烃的降解进程和对正构烷烃的总降解率,以及温度对降解速率的影响。石油降解细菌对正构烷烃有明显的降解作用,混合菌株的降解率明显高于单菌株的降解率;在20℃的条件下,经过21 d后,绝大部分的正烷烃被降解,总的降解率为94.93%。     

3种前处理方法处理婴幼儿配方奶粉中二十二碳六烯酸、花生四烯酸、亚油酸和α-亚麻酸的差异性

探讨了国家标准GB 5009.168-2016中乙酰氯-甲醇甲酯化法、酸水解酯化法和碱水解酯化法3种前处理手段处理婴幼儿配方奶粉中4种多不饱和脂肪酸(二十二碳六烯酸、花生四烯酸、亚油酸和α-亚麻酸)含量的差异性。乙酰氯-甲醇甲酯化法和酸水解酯化法明显优于碱水解酯化法。乙酰氯-甲醇甲酯化法中,样品的水解和脂肪的甲酯化同时进行并相互促进,使得脂肪的释放和甲酯化能够完全进行。通过对反应过程和添加回收率两个方面的考察,证明了乙酰氯-甲醇甲酯化法检测结果的准确性。酸、碱水解酯化法是分别利用酸、碱对样品进行水解,然后提取脂肪进行甲酯化。从水解效率、提取效率及甲酯化效率3个方面对酸、碱水解酯化法进行对比,结果表明,水解效率是影响酸、碱水解差异性的主要因素,酸水解法更适用于婴幼儿配方奶粉中不饱和脂肪酸的测定。通过对实际样品的检测,进一步验证了乙酰氯-甲醇甲酯化法和酸水解酯化法测定多不饱和脂肪酸的准确性,同时对其他食品中脂肪酸的测定具有较强的指导意义。     

聚乙二醇类单体的制备及其生物相容性测定

聚乙二醇类单体是合成功能性高分子材料的重要单体。直接酯化法是合成此类单体的主要方法,但利用该法所制备产物的双键保留率偏低。针对这一问题,本文以聚乙二醇单甲醚-200和丙烯酸为原料,在携水剂存在的同时,向反应体系中引入变色硅胶,提高了直接酯化法去除生成水的效率,制备出了高双键保留率、高产率的聚乙二醇单甲醚-200丙烯酸酯(MPEGA-200),并采用红外光谱、1H NMR对产物进行了表征,采用过氧化氢酶评价了产物的生物相容性。通过正交实验确定了最佳合成条件为:醇酸摩尔比1:2,催化剂对甲苯磺酸和阻聚剂对苯二酚加量均为2%,变色硅胶占醇酸总质量的12%,携水剂石油醚60~90加量为18%,反应温度120℃,反应时间6h。在此条件下,酯化率可达95.47%,MPEGA-200的双键保留率为95.45%,产率为87.68%。另外,本文还采用单因素法研究了各反应条件对酯化反应的影响规律。     

Synthesis of a novel, highly symmetric bis-oxa-bridged compound

A highly oxygenated, novel pentacyclic bis-oxa-bridged compound 8 was synthesized with remarkable efficiency starting from readily available tetrachloro-5,5-dimethoxyclopentadiene and 1,4-cyclohexadiene in three steps. The ruthenium-catalyzed oxidation of 2:1 bis-adduct 1 followed by a one-pot transformation of the resulting bis-alpha-diketone 3 furnished (after esterification) the title compound in an overall yield of 29.1%. The versatility of this simple method was further demonstrated with other norbornyl alpha-diketones to obtain the corresponding strained oxa-bridged derivatives.     

Solvent-free synthesis and properties of carboxymethyl starch fatty acid ester derivatives

Water-soluble, partially hydrophobized polysaccharides have become attractive due to their potential to act as polymeric surfactants. From carboxymethyl starch (CMS), water-soluble polymeric surfactants were prepared by esterification using two unconvential methods based on (A) a reaction with mixed anhydrides and (B) with methyl laureate (MELA) and methyl esters of the fatty acid complex of rape seed oil (MERO) under ‘solvent-free’ conditions. The obtained CMS derivatives were characterized by structural, surface-active and surfactant performance properties. Esterification using method B was successful in contrast to method A which yielded derivatives with a very low extent of esterification. Although the derivatives reduced the surface tension moderately, they exhibited remarkable emulsifying properties. The performance tests indicated good washing power and antiredeposition efficiency. The results suggest that suitable polymeric surfactants can be prepared by the unconventional esterification method B using both acylation agents. The preparations might substitute the expensive and invasive industrially applied conventional methods.     

Surface only modification of bacterial cellulose nanofibres with organic acids

Bacterial cellulose (BC) nanofibres were modified only on their surface using an esterification reaction with acetic acid, hexanoic acid or dodecanoic acid. This reaction rendered the extremely hydrophilic surfaces of BC nanofibres hydrophobic. The hydrophobicity of BC increased with increasing carbon chain length of the organic acids used for the esterification reaction. Streaming (zeta-) potential measurements showed a slight shift in the isoelectric point and a decrease in ζ_plateau was also observed after the esterification reactions. This was attributed to the loss of acidic functional groups and increase in hydrophobicity due to esterification of BC with organic acids. A method based on hydrogen/deuterium exchange was developed to evaluate the availability of surface hydroxyl groups of neat and modified BC. The thermal degradation temperature of modified BC sheets decreased with increasing carbon chain length of the organic acids used. This is thought to be a direct result of the esterification reaction, which significantly reduces the packing efficiency of the nanofibres because of a reduction in the number of effective hydrogen bonds between them.     

Solvothermal Synthesis of Functional Magnetic Nanoparticles for Biocatalyst

A facile and simple one-step solvothermal method has been developed to synthesize polyethyleneimine (PEI)-modified magnetic nanoparticles. Characterization of morphology, surface charges, crystal structure, and magnetic property confirmed the efficiency of this facile synthesis route. Lipase immobilized on the PEI-modified magnetic nanoparticles was used to synthesize vitamin A palmitate from vitamin A acetate and palmitic acid. The reuse of immobilized lipase can be extended to eight times by removing water during esterification with a conversion rate above 80 % for 12 h.     

固相多肽合成中王树脂和Fmoc/tBu酪氨酸成酯反应的研究

以Fmoc/tBu酪氨酸和王树脂为原料,分别探讨了对称酸酐法、活化酯法和2,6-二氯苯甲酰氯(DCB)法中各种因素对氨基酸与树脂成酯反应的影响。实验表明:对称酸酐法连接率低,而其它两种方法,通过筛选合适的反应介质,均能取得良好结果。在活化酯法中,使用强极性溶剂DMA,弱极性溶剂THF/DCM和混合溶剂45%DMF/THF,反应5h,连接率均可提高到90%以上;在DCB法中,使用弱极性溶剂THF时,反应3h,连接率可达99%。总之,DCB方法是酪氨酸和王树脂成酯反应的最好方法。     

甲酯化气相色谱法检测化妆品中防腐剂十一烯酸及其锌盐

采用硫酸催化甲酯化法检测了化妆品中的十一烯酸及其锌盐,并对甲酯化试剂、硫酸浓度、反应体系含水量、甲酯化温度、反应时间等条件进行了优化,发现反应体系的含水量对产率影响较明显。以5%硫酸甲醇溶液为甲酯化试剂,65℃水浴中反应1 h,正己烷为提取溶剂,采用GC/FID色谱法测定,外标法定量。十一烯酸甲酯产率达95%以上,该方法在0.05～1.0 mg范围内线性良好(r>0.999),检出限和定量下限分别为0.001 2%和0.004%。膏霜、乳液、化妆水和洗手液中十一烯酸的平均回收率为93%～104%,相对标准偏差为0.39%～5.1%。     

四甲基氢氧化铵降解苯酐固化双酚A型环氧树脂的研究

将四甲基氢氧化铵(TMAH)降解聚酯的方法移植用于降解苯酐(PA)固化双酚A型环氧树脂(DGEBA),降解生成的邻苯二甲酸二甲酯(DMP)可被气相色谱―质谱(GC-MS)快速检测到,同时通过内标法考察了TMAH用量对降解率的影响,结果表明TMAH降解苯酐固化环氧树脂效率较高,甲酯化率在95%以上。此项研究为剖析毫克级酸酐固化环氧树脂中的固化剂提供了一种快速且有效的方法。     

Photochemical transformations of sphingosine and serinol in aqueous and ethanol solutions

It has been established that the main products of the direct photolysis of C15-sphingosine and serinol are 2-tridecenal and glycolaldehyde, which are formed as a result of C–C bond cleavage in the parent compounds. It has been shown that the addition of hydrogen peroxide and acetone to the test solutions extended the range of the photolysis products due to the occurrence of deamination processes. The set of the experimental data has made it possible to propose mechanisms for the photochemical reactions of C15- sphingosine and serinol fragmentation, which occur through the steps of the formation of N- and C-centered radicals.