Mail module array limits

I want to send emails to 2700 addresses selected from a MySQL database (an opt-in list). I am using the Mail module, assembling the addresses into an array, and passing that to the module. I have done this before with a few hundred addresses, but in this case, it fails. I know that some of the addresses are no longer good, as a number of them bounce back to a special return box. I have no way of knowing how many were delivered, but I added a special one to the end of the array, and it was not delivered, so I have to assume that not all are going out. My thought is that there is a limit to the size of the array that Mail can handle. I have not tried using the builtin PHP mail function. Does anyone know a better way to accomplish this? Thanks. Sandy Keathley