A semiconductor device having a low power mode includes a buffer circuit associated with an interface pad, a power management controller, and a wakeup unit for waking up a part of the device from the low power mode. An application identifier is received by the cluster from a client desiring to connect to the application. The gas cylinder is substantially fixed relative to the barrel. A sensor substrate is positioned below the keyboard chassis and has sensor electrodes configured to sense that one or more of the plurality of keycaps is in a pressed position. The method and apparatus are most conveniently constructed as an array of spray emitters fabricated on a single chip, however, the present invention encompasses any apparatus wherein two or more emitters are simultaneously utilized to form an electrospray of a sample that is then directed into a mass spectrometer.