php implode (101) with quotes

You could use array_map():

function add_quotes($str) {
    return sprintf("'%s'", $str);
}

$csv =  implode(',', array_map('add_quotes', $array));

DEMO

Also note that there is fputcsv if you want to write to a file.

$array = array('lastname', 'email', 'phone');


echo "'" . implode("','", $array) . "'";