【作者】 张晓凤；

【导师】 徐溢；

【作者基本信息】 重庆大学 ， 分析化学， 2004， 硕士

【摘要】 微型全分析系统(Miniaturized Total Analysis System ,(TAS)是近年来发展起来的分析化学研究新领域,其最终目标是在几厘米大小的芯片上实现化学全分析过程。目前的研究主要集中在微芯片上的混合、反应、检测等方面,微芯片上样品的分离富集等预处理过程涉及较少。本文提出采用原位聚合技术,在毛细管玻璃微管道内原位制备出阴离子交换型的固相萃取(SPE)微柱,将其与微流控芯片接合起来,形成带有SPE微柱的复合式微流控芯片。利用相应分析测试手段验证了原位聚合SPE微柱分离富集的性能,在复合式微流控芯片上实现样品的分离富集、混合、反应、检测等过程。本论文主要考察了热引发、密闭条件、反应时间等聚合反应影响因素,分析了聚合反应各组分对SPE微柱性能的影响,制备出原位聚合阴离子交换型SPE微柱。通过SEM表征了原位聚合法制备的SPE微柱具有多孔网状结构,显微观察法与SEM表征法结合起来,证实在有致孔剂存在的条件下有利于原位聚合反应形成多孔网状结构的SPE微柱。用KBrO3—溴百里酚蓝—NO2—催化光度法分析了Φ4mm、柱长2cm的常规SPE柱对NO2—阴离子的吸附作用,吸附效率为65.1%。紫外(UV)法测试了常规SPE柱对NO2—的富集作用,富集倍数为30.3;缩微化的Φ400μm,柱长2cm的SPE微柱对NO2—的富集倍数为29.0;用SPE微柱对NO2—进行在线富集,在线富集倍数为77.9。在复合式微流控芯片上,利用氨基酸—H2O2—Luminol化学发光体系,验证了SPE微柱对pH=9.60的L—精氨酸和L—苯丙氨酸具有不同的选择性,可利用SPE微柱分离保留性质相差很大的两种组分。针对NaNO2—KI—Luminol化学发光体系构建了复合式微流控芯片体系,讨论了进样方式、流速、检测窗口等的选择,分析了复合式微流控芯片上SPE微柱对NO2—的有效理论塔板数为102,通过漏出曲线法和漏出容量估算法分析了SPE微柱的柱容量。在自制的复合式微流控芯片上,利用NaNO2—KI—Luminol发光体系,实现了午餐肉和自来水中痕量NO2—的在线分离富集、混合反应和检测,测得午餐肉中NO2—的含量为14.63mg/kg,自来水中NO2—的含量为0.052mg/kg。更多还原

【Abstract】 Miniaturized total analysis system ((TAS) is a developing new field of analytical chemistry recently. Its finally goal is that all process of analytical chemistry could be put into and carried out on microchip. Most researchers paid their attention on micro-mixers, micro-reactors and detection, while sample pretreatment process was somehow neglected, such as micro-separation and concentration on micro-fluidic chip. In this paper,the in-situ polymerized monolithic porous polymer which is thermally initiated within a glass micro-column was proposed to applied for solid phase extraction(SPE) and preconcentration. Integrating SPE micro-column and micro-fluidic chip together, a combination micro-fluidic chip with SPE micro-column was established. The capability of SPE micro-column was estimated by selected analytical methods. Analytical process, including perconcentration, mixing, reaction and detection, were realized on the combination micro-fluidic chip at last.In this paper,the factors of temperature, oxygen-free condition and polymerization reaction time were interpreted. Effects of the amount of each monomer on the SPE micro-column properties were discussed. SPE micro-column with anion-exchange sorbent was prepared in-situ at glass capillary. The structure image of polymers were observed by microscopy and scanning electron micrograph (SEM). Porogenic solvent mixture was of advantages in the process of forming porous structure polymers during its polymerization. Absorption charateristic of conventional SPE column was proved by catalytic-kinetic spectrophotometric determination of nitrite, which was a system of nitritre-potassium bromate -bromothymol bule. The results shown that absorption efficiency of the conventional SPE column was 65.1%, and enrichment efficient is 30.3 times. SPE micro-column still was of enrichment capacity, ie. enrichment efficient was 29.0 times. Furthermore, enrichment times could achieve 77.9 times with on-line sample treatment by SPE micro-column. All enrichment efficient for on-line process were obtained by UV determination. According to the different retention property of L—phenylalanine and L—Arginine in pH=9.60 solution, the selectivity of SPE micro-column was discussed by the amino acid-hydroxide-Luminol system. It was feasible to separate components with significantly properties on the self- designed combination micro-fluidic chip. For NaNO2—KI—Luminol, the framework of a micro-fluidic chip was designed. Sampling mode, velocity of flow, detection point of <WP=6>chemiluminescence were discussed. Effective plate number of SPE micro-column for NO2— was calculated. Breakthrough volumes of SPE micro-column for NO2—were systematically investigated by breakthrough curve and predicting methods.Sample of trace nitrite in food and water were concentrated on a combination micro-fluidic chip with SPE micro-column, and examined on-line by a system of NaNO2—KI—Luminol. The contents of nitrite in Luncheon meat and tap water were 14.63mg/kg and 0.052mg/kg respectively.更多还原