Development of high sensitive liquid electrode plasma - Atomic emission spectrometry (LEP-AES) integrated with solid phase pre-concentration

Liquid electrode plasma - Atomic emission spectrometry (LEP-AES) is a novel elemental analysis method where a liquid sample is filled in a micro channel that has a narrow part at the center. High voltage is applied to the solution at the both ends of the channel, and consequently microplasma is generated in the channel. The microplasma is an excitation source for atomic emission spectrometry. The method is suitable for heavy metal detection. In this work, to improve detection limit, we integrated a solid phase extraction (SPE) column on a liquid electrode plasma chip (LEP chip) to improve the sensitivity of this method for lead (Pb) detection. The chip design and flow control technique was proposed based on the point of reducing the necessary eluent for one measurement. Chip pattern was made by Polydimethylsiloxane (PDMS) employing negative photolithography. The integrated chip was successful in detecting 10ppb Pb in solution. Detection limit for Pb of LEP method is improved.