Yes, you may use CPF funds to buy, subject to the rules of the CPF Investment Scheme, including your available gold limit.
Your gold holdings with UOB will be reflected in your CPF Investment Account monthly statement.
You are responsible for ensuring that there are sufficient funds in your CPF Investment Account to buy the gold. If your request to use CPF funds to buy the gold is rejected or you do not have enough CPF funds to do so, you will have to pay cash for the gold. If you do not have sufficient cash to pay for the gold you will have to sell the gold to the Bank and pay for the difference in the price movement between the contracted price and the Bank’s prevailing purchase price.