A disposable screen-printed microchip based on an organic membrane sensitive layer is presented. The microchip is highly responsive for the determination of Lead(II). The microchip is composed of a composite sensitive material which comprises carbon nano-tubes “CNTs” and titanium (IV) oxide nano-particles embedded in a PVC membrane which was deposited on the surface of a plastic screen printed micro-electrode using a new methodology. The prepared disposable microchip provides a linear response for Pb2+ ions covering the concentration range of 1×10−6 to 1×10−1 mole L−1 with high sensitivity (49 mV), a long life span (>4 months) and short response time (10 s). The merits offered by the micro-sensor or microchip include small size, simple fabrication, mass production, integration feasibility and cost effectiveness and automation.