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文章用比值—导数光谱法测定香草醛的含量。实验结果表明,香草醛木素溶液在pH≤7时香草醛在230 nm处有吸收,在pH>7时在248 nm处有吸收。根据不同pH值和不同浓度条件下香草醛木素溶液的比值-导数光谱,说明在230 nm处的光谱信号在pH≤7不受pH值影响,248 nm处的光谱信号在pH>7不受pH值影响。在230 nm和248 nm处的光谱信号对浓度的变化较为敏感,在此两处吸收值可用于香草醛的测定。  相似文献   
2.
The present study investigated capillary electrophoretic detection of vanillin in vanilla perfume and air. An UV-absorbance detector was used in a home-made capillary electrophoretic instrument. A fused silica capillary (outer diameter: 364μm, inner diameter: 50 m) was used as a separation capillary, and a high electric voltage (20 kV) was applied across the two ends of the capillary. Total length of the capillary was 70 cm, and the effective length was 55 cm. Experimental results showed that the vanillin peak was detected at about 600, 450, and 500 seconds when pH of running buffers in CE were 7.2, 9.3, and 11.5, respectively. The peak area of vanillin was proportional to its concentration in the range of 0-10-2 mol/L. The detection limit was about 10-5 mol/L. Vanillin concentration in a 1% vanilla perfume sample was determined to be about 3×10-4 mol/L, agreed well with that obtained by a HPLC method. Furthermore, determination of vanillin in air by combination of CE and active carbon adsorption method was investigated.  相似文献   
3.
香草醛改性壳聚糖的制备及其吸附性能   总被引:18,自引:0,他引:18       下载免费PDF全文
 香草醛经Schiff反应对壳聚糖进行了修饰、研究了产物对Cu2+、Pb2+、Cd2+、Zn2+的吸附性能,同时考察了pH值、时间、温度等因素对吸附的影响结果表明,改性后的壳聚糖具有不流失,易再生的特点,且对金属离子的饱和吸附量比壳聚糖的大(改性后的壳聚糖对Cu2+、Pb2+、Cd2+、Zn2+吸附量分别为 143.5、 558.9、 357.7、178.4mg/g).  相似文献   
4.
Summary. During peak calling activity by male oil palm bunch moths, Tirathaba mundella Walker (Lepidoptera: Pyralidae), their hairpencils, wings or entire body were extracted in hexane. Gas chromatographic-electroantennographic detection (GC-EAD) analyses of hair pencil extracts revealed four compounds that consistently elicited responses from female antennae. The NMR spectrum of isolated compound 1, and mass spectra and retention indices of compounds 1–4 suggested that they were (3S,6S)-2,2,6-trimethyl-6-vinyl-tetrahydro-pyran-3-ol (1), 4-hydroxy-3-methoxy-benzaldehyde (2, vanillin), 6,10,14-trimethyl-2-pentadecanone (3), and 6,10,14-trimethyl-2-pentadecanol (4). Comparative GC and GC-MS analyses of hair pencils extract and synthetic standards confirmed these structural assignments. Moreover, comparative chromatography of synthetic and hairpencil-isolated 1 on a Cyclodex-B column (which separated the four stereoisomers with baseline resolution) revealed that male T. mundella produce the SS-stereoisomer (SS-1). In field cage bioassay experiments in Palembang, Indonesia, synthetic SS-1 and vanillin in combination, but not singly, attracted female T. mundella. SS-1 plus vanillin were as effective as male T. mundella in attracting females. Compounds 3 and 4 did not enhance the blend's attractiveness. Received October 11 2002; accepted March 14, 2003. R1D=" Correspondence to: Gerhard Gries, email: gries@sfu.ca  相似文献   
5.
The present study investigated capillary electrophoretic detection of vanillin in vanilla perfume and air. An UV-absorbance detector was used in a home-made capillary electrophoretic instrument. A fused silica capillary (outer diameter: 364 μm, inner diameter: 50 μm) was used as a separation capillary, and a high electric voltage (20 kV) was applied across the two ends of the capillary. Total length of the capillary was 70 cm, and the effective length was 55 cm. Experimental results showed that the vanillin peak was detected at about 600, 450, and 500 seconds when pH of running buffers in CE were 7.2, 9.3, and 11.5, respectively. The peak area of vanillin was proportional to its concentration in the range of 0–10?2 mol/L. The detection limit was about 10?5 mol/L. Vanillin concentration in a 1% vanilla perfume sample was determined to be about 3×10?4 mol/L, agreed well with that obtained by a HPLC method. Furthermore, determination of vanillin in air by combination of CE and active carbon adsorption method was investigated  相似文献   
6.
采用微波辐射技术合成了香草醛交联壳聚糖(V-CTS)希夫碱,用红外光谱和扫描电镜对产物结构进行了表征,研究了该吸附剂对镉离子的吸附性能。结果表明,香草醛改性壳聚糖粒径约在5~40μm之间,吸附剂对镉离子的的吸附条件是:pH为6.0,100 mg/LCd2+溶液50 mL,吸附剂投加量为0.02 g,吸附震荡时间5 h,温度20℃,吸附量为39.7 mg/g。与水浴法制备的吸附剂以及其他壳聚糖改性产品相比,该吸附剂的吸附量大大提高,且操作方法简单,工艺条件易于控制。  相似文献   
7.
核废料中的放射性碘对环境的污染日趋严重,固定回收放射性碘对核能的可持续发展至关重要.本文通过醛胺缩合制备了两种席夫碱共价材料—3,5-二氨基苯甲酸缩合香草醛(SB-35)和4-氨基安替比林缩合香草醛(SB-4),并采用傅里叶变换红外光谱仪(FT-IR)、热重分析仪(TGA/DSC)、X-射线粉末衍射仪(XRD)、场发射扫描电子显微镜(SEM)等对两种材料的结构和形貌分别进行了表征.结果表明,两种席夫碱材料对水中碘具有较好的吸附效果,吸附行为更符合Freundlich等温吸附模型,表明该吸附过程以多分子层吸附为主;由Langmuir等温吸附可知,在25℃时SB-35和SB-4的最大理论吸附量分别为1356.49 mg·g-1和1680.08 mg·g-1.吸附热力学结果表明,两种材料对水中碘的吸附是吸热反应且自发进行,升高温度有利于反应进行.  相似文献   
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为缓解地下水污染原位生物修复过程中生物膜形成造成的多孔介质渗透性损失,采用纳米乳化油为碳源,市售反硝化细菌为菌种,开展静态批实验,模拟地下水硝酸盐氮反硝化修复过程;选取蛋白酶、多糖酶以及群体感应抑制剂香草醛为生物膜抑制剂,分析不同反应体系硝酸盐氮的降解情况,探究3种添加物的不同组合方式对于反硝化细菌生物膜的抑制作用.结果显示,多糖酶、蛋白酶以及香草醛的投加能够有效促进硝酸盐氮的降解和亚硝酸盐氮的还原.4个实验组别的NO3-N降解速率为0.28~0.30 mg·L-1·h-1,约为空白组的2.55~2.73倍,且NO2-N无明显积累.群体感应抑制剂香草醛与蛋白酶的结合对以假单细胞菌属为主的反硝化细菌生物膜的抑制效果最好.定量评估结果表明,生物膜去除效果依次为香草醛和蛋白酶的混合物(81.3%)>蛋白酶和多糖酶的混合物(68.6%)>蛋白酶(54.1%)>多糖酶(49.1%),单位质量多糖酶、蛋白酶和香草醛对于胞外聚合物的去除量分别为30.07、65.34 mg·mL-1  相似文献   
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