Systems and methods for monitoring analytes in real time using integrated chromatography systems and devices. Integrated microfluidic liquid chromatography devices and systems include multiple separation columns integrated into a single substrate. Using such a device, parallel analysis of multiple samples can be performed simultaneously and/or sequential analysis of a single sample can be performed simultaneously on a single chip or substrate. The devices and systems are well suited for use in high pressure liquid chromatography (HPLC) applications. HPLC chips and devices including embedded parylene channels can be fabricated using a single mask process.