Development of an Ultra-micro Sample Injector for Gas Chromatography Using an Ink-jet Microchip

An ultra-micro sample injector for gas chromatography (GC) was developed. An ink-jet microchip, originally used for industrial recorder, was modified at the edge near to an orifice, and fixed into the GC. In order to evaluate the characteristics of this injector, a sample injector and a thermal conductive detector (TCD) were connected directly, while water was used as the test sample. The volume of the droplet, the interval time and the back-pressure to the ink-jet microchip were investigated. Within the range of 1 - 5 nL volume injected sample, the TCD response according to the amount of the sample volume (the volume of one droplet from the ink-jet microchip was about 1 nL) was obtained. A good reproducibility of the peak area was obtained to be about 1.0% of the RSD value. In order to compare the injection method of the ink-jet chip with that using a micro-syringe, the method using the ink-jet chip could introduce 1/1000 of the amount of the sample and gave reproducible results.