We present the fabrication and characterization of a TiO 2 affinity chromatography microcolumn on Si substrates to analyze phosphopeptides. The microfabricated column consisted of 32 parallel microchannels with common input and output and was fabricated by lithography and plasma etching of the Si substrate and sealed with lamination, while RF sputtering of TiO 2 target was used for producing the stationary phase. The chip was characterized by standard mono-phosphopeptide separation and detection with UV absorption spectroscopy. The chip design allows an expansion of its capacity by means of increasing the number of parallel microchannels at a constant sample volume.