Copy a register's content to an immediate memory address in assembly

Question

In MASM 32 how can I copy the value of a register (for example AL) to an immediate fixed address in the memory (for example address 30h). So like this

MOV [address], register

I tried this with MOV

MOV [30H], AL

and this also

MOV DS:[30H], AL

but it didn't work, so what to do?