An advance made under RCW 43.03.150 through 43.03.210 shall be considered as having been made to such officer or employee to be expended by him or her as an agent of the state for state purposes only, and specifically to defray necessary costs while performing his or her official duties. No such advance shall be considered for any purpose as a loan to such officer or employee, and any unauthorized expenditure of such funds shall be considered a misappropriation of state funds by a custodian of such funds.