Abstract: Disclosed are nanofluidic analytical devices. The devices employ a sample processing region that includes a plurality of fluidically connected sample handling elements that, in combination, affect a physical change on a sample introduced into the sample processing region. This physical change can include, for example, purification of an analyte of interest present in the sample, concentration of an analyte of interest present in the sample, chemical modification (e.g., cleavage and/or chemical derivatization) of an analyte of interest present in the sample, or a combination thereof. The analytical devices further include a nanochannel comprising a plurality of in-plane nanopores in series fluidically coupled to the sample processing region. The in-plane nanopores can be used to detect and/or analyze analyte(s) present in the sample following processing by the sample processing region. These analytical devices can advantageously provide for the label-free detection of single molecules.