PHP parse_str of URL query returns array keys with 'amp' in key name

&'amp; must only be used when outputting URLs in HTML/XML data.

You can try use html_entity_decode()

$querystring = "ie=UTF8&qid=1468851514&sr=8-1&keywords=there&tag=sitename-20";
parse_str(html_entity_decode($querystring), $queryarray);
echo "<pre>";
print_r($queryarray);
echo "</pre>";

I hope it help.