A method of sample processing, comprising: providing a fluidic device with at least one microfluidic or nanofluidic separation channel in fluid communication with a background electrolyte (BGE) reservoir , a nanofluidic or microfluidic sample channel in fluid communication with the separation channel , wherein the sample channel comprises at least one solid phase extraction (SPE) bed , a sample reservoir in fluid communication with the sample channel , a waste reservoir in fluid communication with the sample channel , and a waste channel that fluidly connects the waste reservoir to the separation channel ; flowing a sample through the sample channel , across the at least one SPE bed , and into the separation channel , by pressurizing sealed headspaces of the BGE reservoir , the sample reservoir , and the waste reservoir without applying a voltage to the sample reservoir , to the BGE reservoir , or to the waste reservoir and/or with no electric potential gradient in any of the sample channel, the BGE channel and the waste channel; electrophoretically separating an analyte component from the sample in the separation channel ; and performing at least one of: (a) electrospraying the analyte component from at least one emitter in fluid communication with the separation channel toward at least one of a collection device or an inlet of a mass spectrometer ; and (b) detecting a signal corresponding to the analyte component in, or emerging from, the separation channel . providing a fluidic device with at least one microfluidic or nanofluidic separation channel in fluid communication with a background electrolyte (BGE) reservoir , a nanofluidic or microfluidic sample channel in fluid communication with the separation channel , wherein the sample channel comprises at least one solid phase extraction (SPE) bed , a sample reservoir in fluid communication with the sample channel , a waste reservoir in fluid communication with the sample channel , and a waste channel that fluidly connects the waste reservoir to the separation channel ; flowing a sample through the sample channel , across the at least one SPE bed , and into the separation channel , by pressurizing sealed headspaces of the BGE reservoir , the sample reservoir , and the waste reservoir without applying a voltage to the sample reservoir , to the BGE reservoir , or to the waste reservoir and/or with no electric potential gradient in any of the sample channel, the BGE channel and the waste channel; electrophoretically separating an analyte component from the sample in the separation channel ; and performing at least one of: (a) electrospraying the analyte component from at least one emitter in fluid communication with the separation channel toward at least one of a collection device or an inlet of a mass spectrometer ; and (b) detecting a signal corresponding to the analyte component in, or emerging from, the separation channel . (a) electrospraying the analyte component from at least one emitter in fluid communication with the separation channel toward at least one of a collection device or an inlet of a mass spectrometer ; and (b) detecting a signal corresponding to the analyte component in, or emerging from, the separation channel . <EOS>