高效液相色谱法分析地瓜儿多糖的单糖组成

研究分析地瓜儿多糖的单糖组成。采用水提醇沉法提取地瓜儿多糖,用三氟乙酸水解多糖成单糖,单糖产物经衍生化试剂1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生化后,利用高效液相色谱法分析单糖的PMP衍生物。结果表明,地瓜儿多糖由甘露糖(Man)、鼠李糖(Rha)、葡萄糖醛酸(GlcUA)、半乳糖醛酸(GalUA)、葡萄糖(Glc)、半乳糖(Gal)、木糖(Xyl)和阿拉伯糖(Ara)8种单糖组成,是一种酸性杂多糖,其中以半乳糖、葡萄糖和半乳糖醛酸为主,为进一步开发利用地瓜儿这一新的野菜资源提供了科学依据。     

ICP-OES法和离子色谱法测定水中钙、镁比对研究

目的:对ICP-OES法和离子色谱法测定水中钙、镁两种元素方法进行比对研究。方法:分别采用ICP-OES法和离子色谱法对不同水源10个水样进行比对测定。结果:两种方法灵敏度、准确度、精密度相当,但ICP-OES分析速度较离子色谱提高10倍。结论:ICP-OES法和离子色谱法均适用于水样中微量、常量钙、镁含量的测定,但ICP-OES法分析速度快,且具有多元素同测的特点,更适合于批量样品分析。     

铜陵白姜精油分析研究

利用水蒸气蒸馏法和同时蒸馏-萃取法(SDE)萃取铜陵白姜姜精油,并通过GC/MS方法进行定性、定量分析。结果显示,SDE法能够有效地提取到姜精油,经GC/MS分析鉴定出87种组分。以色谱峰面积归一化法测定各成分的相对百分含量,含量最高的是姜烯(21.91%),其次是乙酸香叶酯(12.45%)、β-倍半水芹烯(11.76%)、金合欢烯(11.73%)。乙酸香叶酯在铜陵白姜中含量较高。     

Centrifugal partition chromatography applied to the isolation of oak wood aroma precursors

Flavours extracted from oak wood during barrel ageing contribute to the organoleptic character of wines and spirits. The aim of this work was to identify the glycosidic precursors of the key volatile compounds responsible for oak wood aroma. Oak extract is a very complex matrix and, furthermore, precursors are present in very small quantities. Preparative centrifugal partition chromatography (CPC) is a promising solution for purifying the oak extract. The solvent system was selected on the basis of the partition coefficient of glycosidase enzyme activity (K_ca). Thanks to the efficacy of CPC separation, three glucoside gallates were subsequently isolated by HPLC chromatography. Vanillin-(6′-O-galloyl)-O-β-d-glucopyranoside, 3,4,5-trimethoxyphenyl-(6′-O-galloyl)-O-β-d-glucopyranoside, and (6R,9R)-3-oxo-α-ionol-9-O-(6′-O-galloyl)-β-glucopyranoside (macarangioside E) were isolated and identified. This was the first time that vanillin-(6′-O-galloyl)-O-β-d-glucopyranoside was identified and the first time that macarangioside E was isolated from oak wood. Heating macarangioside E resulted in the formation of megastigmatrienone, which has an aroma reminiscent of tobacco.     

新型复合保鲜纸的制备及在油桃保鲜中的应用

为提高油桃果实的保鲜效果,制备了一种以PVA涂层为阻隔层,以牛至精油和1-甲基环丙烯(1-MCP)为保鲜剂,既能抑菌又能抑制乙烯活性、延缓呼吸越变进程的新型复合保鲜纸。并采用GC-MS对精油抑菌成分和1-MCP的释放规律进行了研究;以油桃为供试水果,通过测定呼吸强度和腐烂指数,考察自制复合保鲜纸的实际保鲜效果。结果表明,这种新型的复合保鲜纸的保鲜效果明显优于单独使用牛至精油或1-MCP,可以明显降低油桃的腐烂指数。这种新型复合保鲜纸对呼吸跃变型的油桃具有良好的保鲜效果,为这类果蔬的保鲜提供了一种有效方法。     

高效液相色谱测定广西生鲜乳中的维生素A

为了建立生鲜乳中维生素A的一种快速、准确、灵敏度高的检测方法,样品经皂化后,经石油醚提取,浓缩后采用高效液相色谱法,以Shim-pack VP-ODS柱(4.6 mm×150 mm,5μm),柱温35℃,检测波长325 nm,流动相为甲醇∶水(98∶2,体积比),流速1.0 mL/min的条件进行实验。结果维生素A在0.174～87.2μg/mL范围内线性关系良好,相关系数r=0.9999,平均回收率为98.17%,RSD=1.90%。建立的方法准确、可靠,可以用于生鲜乳中维生素A的含量检测。     

自动进样顶空气相色谱法测定浓缩果汁中的乙醇

建立了测定浓缩果汁中乙醇含量的自动进样顶空气相色谱分析方法。对实验条件进行了优化。实验结果表明该方法线性范围宽，标准曲线相关系数为0．99908，平均回收率为98．01～101．86％，相对标准偏差均小于2．5％，方法的重现性好；另外，该方法简便、快速、准确，应用于浓缩果汁的测定结果满意。     

Aroma profiles of five basil (Ocimum basilicum L.) cultivars grown under conventional and organic conditions

A headspace solid-phase microextraction (HS-SPME) method coupled to gas chromatography–ion trap mass spectrometry (GC–ITMS) has been developed and applied for profiling of volatile compounds released from five Ocimum basilicum L. cultivars grown under both organic and conventional conditions. Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC–TOFMS) was employed for confirmation of identity of volatiles extracted from the basil headspace by SPME.     

Spiral column configuration for protein separation by high-speed countercurrent chromatography

Retention of the stationary phase of aqueous–aqueous polymer phase systems is improved by a spiral column configuration which utilizes the radially acting centrifugal force along the spiral pitch to retain the heavier phase in the outer portion and the lighter phase in the inner portion of the spiral channel. For the separation of proteins which has low mass transfer rates, the system needs further modification of the separation channel to interrupt the laminar flow and enhance mixing of the two phases.     

6-APA中残留丙酮、甲基异丁基酮的测定

采用直接进样色谱法测定,并用内标法（2-戊酮作内标物）定量,确定6-APA中残留丙酮、甲基异丁基酮的检测方法。经验证此法可准确测定6-APA中丙酮、甲基异丁基酮的残余量。