Get hard drive serial number

Hello

I want to get hard drive serial number

I use this code, but its give me the serial number starting with big space, like this
( SPACE ) 33LDW6PVT
PHOTO : https://drive.google.com/open?id=1hK...U60ywP0cgKrbSt
I want it without the space like this
33LDW6PVT

what can i do?

Dim s As String
Dim itm As Object
With GetObject("winmgmts:\\.\root\CIMV2")
For Each itm In .ExecQuery("SELECT * FROM Win32_DiskDrive", , 48)
s = itm.SerialNumber
Next itm
End With
End Sub

thanks