Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia.
J Chromatogr A. 2013 Jan 4;1271(1):185-91. doi: 10.1016/j.chroma.2012.11.025. Epub 2012 Nov 19.
An integrated gas chromatographic system has been successfully developed and implemented for the measurement of oxygen, nitrogen, carbon monoxide, carbon dioxide and light hydrocarbons in one single analysis. These analytes are frequently encountered in critical industrial petrochemical and chemical processes like catalytic cracking of naphtha or diesel fuel to lighter components used in gasoline. The system employs a practical, effective configuration consisting of two three-port planar microfluidic devices in series with each other, having built-in fluidic gates, and a mid-point pressure source. The use of planar microfluidic devices offers intangible advantages like in-oven switching with no mechanical moving parts, an inert sample flow path, and a leak-free operation even with multiple thermal cycles. In this way, necessary features such as selectivity enhancement, column isolation, column back-flushing, and improved system cleanliness were realized. Porous layer open tubular capillary columns were employed for the separation of hydrocarbons followed by flame ionization detection. After separation has occurred, carbon monoxide and carbon dioxide were converted to methane with the use of a nickel-based methanizer for detection with flame ionization. Flow modulated thermal conductivity detection was employed to measure oxygen and nitrogen. Separation of all the target analytes was achieved in one single analysis of less than 12 min. Reproducibility of retention times for all compounds were found to be less than 0.1% (n=20). Reproducibility of area counts at two levels, namely 100 ppm(v) and 1000 ppm(v) over a period of two days were found to be less than 5.5% (n=20). Oxygen and nitrogen were found to be linear over a range from 20 ppm(v) to 10,000 ppm(v) with correlation coefficients of at least 0.998 and detection limits of less than 10 ppm(v). Hydrocarbons of interest were found to be linear over a range from 200 ppb(v) to 1000 ppm(v) with correlation coefficients of greater than 0.999 and detection limits of less than 100 ppb(v).
已经成功开发并实施了一种集成气相色谱系统，可用于在单次分析中测量氧气、氮气、一氧化碳、二氧化碳和轻烃。这些分析物经常在催化裂化石脑油或柴油以生产用于汽油的较轻组分等关键工业石油化工和化学过程中遇到。该系统采用了一种实用且有效的配置，由两个三端口平面微流控器件串联而成，内置流体门和中点压力源。使用平面微流控器件具有无形的优势，例如在没有机械运动部件的情况下进行烤箱内切换、惰性样品流路以及即使经过多个热循环也能实现无泄漏操作。通过这种方式，实现了选择性增强、柱隔离、柱反冲洗和提高系统清洁度等必要的功能。多孔层开管毛细管柱用于分离烃类，然后用火焰电离检测。分离完成后，使用镍基甲烷化器将一氧化碳和二氧化碳转化为甲烷，然后用火焰电离检测。采用流量调制热导检测测量氧气和氮气。所有目标分析物都在不到 12 分钟的单次分析中实现了分离。所有化合物的保留时间重现性都小于 0.1%（n=20）。在两天的时间内，在两个水平（即 100 ppm(v) 和 1000 ppm(v)）上的面积计数重现性都小于 5.5%（n=20）。氧气和氮气在 20 ppm(v) 至 10,000 ppm(v) 的范围内呈线性，相关系数至少为 0.998，检测限小于 10 ppm(v)。感兴趣的烃类在 200 ppb(v) 至 1000 ppm(v) 的范围内呈线性，相关系数大于 0.999，检测限小于 100 ppb(v)。
