<?php


$string =  "PHP is the website scripting @ language of choice.";

$find = "website scripting @";
$find = preg_quote($find);
if (preg_match('/\w$/u', $find)) {            //  Setting trailing word boundary
    $find .= '\\b'; 
}

if (preg_match('/^\w/u', $find)) {            //  Setting leading word boundary
    $find = '\\b' . $find;
}

if (preg_match("/" . $find . "/ui", $string)) {
    echo "A match was found.";
} else {
    echo "A match was not found.";
}