How do I correctly utilize the IF and isblank function when trying to hardcode Formulas in VBA?

I have the following hardcoded formula in vba, which keeps giving me an error when i try to execute it. Is it the """" that is causing the syntax error? Thanks in advance.

IF(isnblank(VLOOKUP([@[Uid]],tblProjectPlan[[Uid]:[Adjusted Sart]],13,false)),"""",VLOOKUP([@[Uid]],tblProjectPlan[[Uid]:[Adjusted Start]],13,false))