formatting cmdlt to eject USB via Powershell

I need the ability to eject usb drives in a deployed program (Windows 10, R2019b), and TMW sadly still does not provide this functionality.

When I enter the concatenated cmdlt into the Windows Command Prompt window, it ejects the usb. When Invoke PowerSheel from the ML Command Window and enter the concatenated_cmdlt it also ejects the usb. However, when I execute !powershell concatenated_cmdlt or system('powershell concencatenated_cmdlt'), ML returns the following error message:

At line:1 char:92

+ ... bject Shell.Application; $driveEject.Namespace(17).ParseName(G:).Invo ...

+ ~

Missing ')' in method call.

At line:1 char:92

+ ... ect Shell.Application; $driveEject.Namespace(17).ParseName(G:).Invoke ...

+ ~~

Unexpected token 'G:' in expression or statement.

At line:1 char:94

+ ... ct Shell.Application; $driveEject.Namespace(17).ParseName(G:).InvokeV ...

+ ~

Unexpected token ')' in expression or statement.

+ CategoryInfo : ParserError: (:) [], ParentContainsErrorRecordException

+ FullyQualifiedErrorId : MissingEndParenthesisInMethodCall

I've read through all PS related Answers and have fiddled with single-quotes and double-quotes until the version below , which does not error but also does not do anything. Openng system.m yielded no info and neither did other forums.

I am hoping for a resolution, otheriwse I will need to deploy under linux where this is peanuts.

Thanks

function ejectusb(driveletter)
% this function removes the usb drive if it is not busy

% the original cmdlts were lifetd from:
% https://serverfault.com/questions/130887/dismount-usb-external-drive-using-powershell
%     $driveEject = New-Object -comObject Shell.Application
%     $driveEject.Namespace(17).ParseName("G:").InvokeVerb("Eject")

% in powershell this concatenated version worked fine
%     $driveEject = New-Object -comObject Shell.Application; $driveEject.Namespace(17).ParseName("G:").InvokeVerb("Eject")

% the reworked version does not crash, but also not remove the usb

usbdrive = [driveletter, ':'];

if exist(usbdrive, 'dir')   
   % double-check thar all files are closed
   fclose('all');
   
   % eject USB - this does not work
   % this reworked version was the olny version that dis not crash, but also did not remove the usb
   system(['powershell $driveEject = New-Object -comObject Shell.Application;',...
                       '$driveEject.Namespace(17).ParseName('''               ,...
                       usbdrive                                               ,...
                       ''').InvokeVerb(''Eject'')']);
   
   % check for result
   if exist(usbdrive, 'dir')
      disp('could not remove the usb drive')
   else
      disp('usb drive removed')
   end
end