Adams County has purchased a building in Westminster's Park 12 Hundred master-planned business park for $9.8 million in the largest single-tenant office building sale so far in 2014. The building is located at 1200 W. 120th Ave. and encompasses 297,172 square feet. "Not that long ago we were working on a strategy for the underutilized campus," said Jason Addlesperger, executive managing director at Newmark Grubb Knight Frank, which represented seller IBC Holdings on the transaction. "After guiding…