Compact Elemental Analysis System Equipped with an Inkjet Microchip for Pico-Liter Droplet Injection and a Finger-Sized Atomic Emission Detector

A compact elemental-analysis system equipped with an inkjet microchip for sample injection, and a finger-size atomic emission detector using a helium radio-frequency plasma was developed. The detection performance of the elemental analysis system was evaluated by using 1,1,1-trichloro-2-methyl-2-propanol (chloretone) dissolved in isopropanol as the sample. When 5100 droplets of isopropanol were ejected from the inkjet microchip, the ejection volume of one droplet was estimated to be 463 pl from the result that the 5100 droplets ejection volume was measured to be 2.36±0.04 μl (n = 5). A linear relationship was obtained between the emission intensity at 837.6 nm from chlorine and the number of ejected droplets or the concentration of the sample solution The repeatability of the emission intensity (peak height) obtained with the one-droplet injection of a 2.5 mg/ml sample solution was calculated to be 7.1% RSD (n = 6). The detection limit of chloretone resulted to be 184 pg (S/N = 3). The detectable concentration of the sample solution was estimated to be 85 μg/ml by the injection of four droplets of the sample solution.