The department shall prescribe an exemption certificate for use by persons purchasing items exempt pursuant to items (5), (6), (7), (16), (18), (32), and (44) of § 12-36-2120. This exemption certificate may be presented upon each purchase by the holder, or the retailer may keep a copy of the certificate on file. When an exempt sale is made pursuant to a certificate on file, the purchaser must note on the purchase invoice the exempt items and state that the items are to be used for exempt purposes. When the purchase order meets the requirements of this section, the liability for any tax determined to be due is solely the purchaser’s.