On-column micro gas chromatography detection with capillary-based optical ring resonators
On-column micro gas chromatography detection with capillary-based optical ring resonators
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DOI：
10.1021/ac702389x
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发表时间：
2008-03-15
影响因子：
7.4
通讯作者：
Ja, Shiou-jyh
中科院分区：
文献类型：
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作者：
Shopova, Siyka I.;White, Ian M.;Ja, Shiou-jyh
我们开发了一种新的柱上微气相色谱（μ GC）检测器，使用毛细管为基础的光环谐振器（CBORR）。CBORR是一种薄壁熔融石英毛细管，内径范围从几十微米到几百微米。CBORR的内表面涂有一层用于气体分离的固定相。CBORR的圆形横截面形成环形谐振器并且支持沿着环形谐振器圆周沿着循环数百次的回音壁模式（WGM）。渐逝场延伸到芯部中，并且对由气体样品与固定相之间的相互作用引起的折射率变化敏感。通过将锥形光纤放置在CBORR上，可以在沿CBORR的任何位置沿着激发和监测WGM，从而实现柱上实时检测。极性和非极性样品的快速分离证明了亚秒级的检测速度。理论工作也建立了解释CBORR检测机制。虽然在这些初步测试中观察到低纳米级检测限，但正在研究许多改进方法。CBORR与传统的毛细管GC色谱柱直接兼容，没有任何死体积。因此，基于CBORR的μ GC是一种非常有前途的快速、灵敏和便携式分析设备的技术平台。
We developed a novel on-column micro gas chromatography (mu GC) detector using capillary based optical ring resonators (CBORRs). The CBORR is a thin-walled fused silica capillary with an inner diameter ranging from a few tens to a few hundreds of micrometers. The interior surface of the CBORR is coated with a layer of stationary phase for gas separation. The circular cross section of the CBORR forms a ring resonator and supports whispering gallery modes (WGMs) that circulate along the ring resonator circumference hundreds of times. The evanescent field extends into the core and is sensitive to the refractive index change induced by the interaction between the gas sample and the stationary phase. The WGM can be excited and monitored at any location along the CBORR by placing a tapered optical fiber against the CBORR, thus enabling on-column real-time detection. Rapid separation of both polar and nonpolar samples was demonstrated with subsecond detection speed. Theoretical work was also established to explain the CBORR detection mechanism. While low-nanograrn detection limits are observed in these preliminary tests, many methods for improvements are under investigation. The CBORR is directly compatible with traditional capillary GC columns without any dead volumes. Therefore, the CBORR-based mu GC is a very promising technology platform for rapid, sensitive, and portable analytical devices.