Consistent with Division II of this article, the Secretary or the Chief Procurement Officer shall contract for or purchase any supplies or services for a unit except: an item that the Secretary or Chief Procurement Officer: determines is strictly perishable; determines is impracticable for the unit to purchase through or with the approval of the Secretary or Chief Procurement Officer; or permits the unit to purchase with the approval of the Secretary or Chief Procurement Officer; or supplies or services authorized by statute to be procured by another primary procurement unit or delegated to another unit.