An electrospray device for a mass spectrometry system is described. The expression vector comprises a DNA coding sequence for a blood coagulation factor operably linked to a liver-specific promoter and a liver-specific enhancer, wherein the promoter and enhancer are derived from different genes. These characteristic values are transmitted to a central monitoring unit via a low-speed line. At steady state operating conditions the first and the second stream respectively acts as the driving force for the steam compressor and the inlet feed to the steam compressor generating the high pressure steam.