Ubuntu :: Using BASH Script To Unmount A Volume?

As part of a script for imaging floppy disks on a Mac, I am trying to unmount the volume located at /dev/disk1

In my script I put--
#!/bin/sh
echo "This should unmount the external floppy drive."
sudo umount /dev/disk1

But I get an error--
umount: /dev/disk1
: not currently mounted

I also tried excluding the "sudo" with the same result. Any ideas where the " is coming from or what else might be the problem?

sudo umount /dev/disk1 works when I use it in the command line, but as a long term solution I need it in my script if possible.