EXHIBIT 10.21 STOCK PURCHASE AGREEMENT THIS AGREEMENT is by and among THERMO BIOANALYSIS CORPORATION (the "Company"), a Delaware corporation with an office at 504 Airport Road, Santa Fe, New Mexico 87504; THERMO ELECTRON CORPORATION ("Thermo...Stock Purchase Agreement • January 21st, 1997 • Thermo Bioanalysis Corp /De • Laboratory analytical instruments • Massachusetts
