Dead volume free micro-machined electro-spray chip for mass spectrometry

Design and fabrication themes of a dead volume free electro-spray chip for mass spectrometry based on mechanical micro-machining approach is discussed in this article. To implement the dead volume free concept, a cantilever needle is embedded inside the micro-channel of the spray-chip such that there is no connecting joint between the sample wall and the spray-tip. To ensure that the proposed spray-chip is able to produce efficient Taylor cone, embedded needles with different cone angles are fabricated to produce an efficient experiment. Experiments to distinguish amphetamine by a LCQ type mass spectrometry are conducted. Experimental results show that the proposed dead volume free electro-spray chip is able to reach the desired goal. It is also found from the experiments that the ringlike cross-section of the needle embedded micro-channel is critical to the stability of the Taylor cone at the spray-tip. To ensure a stable Taylor cone can be produced at the spray-tip, an embedded needle with a smaller diameter is desired.