where() showing "IS NULL" instead of variable value

Hello guys,

$email=''abc@abc.com';
$pass= 123;

$this->db->select('*')->from('user')->where(' email',$email)->where('password',$pass)-> get()->result();

this gives result :-

'select * from uses where email IS NULL and password IS NULL';

But it works with $this->db->query();

plz help me to find why its not taking like :-

'select * from user where email="abc@abc.com" and password="123" ';

Thanks,