regular expression using lookahead negative assertion

regular expression using lookahead negative assertion

Using php I would like to detect something in a string depending on
whether the part immediately after the matched part does not contain
certain characters. I think I may need to use a lookahead negative
assertion but it is not working as I would expect so not sure. So for
example:
$string = 'test somerandomURL><b>apple</b> peach orange';
I want an expression that will detect everything up to the first > so long
as <b>apple</b> does not immediately follow the first >
I tried
if(preg_match("/test(.*)>(?!<b>apple</b>)(.*))/i",$string)){
echo 'true since <b>apple</b> does not follow > in string';
}else{
echo 'false since <b>apple</b> follows > in string';
}
When the string contains <b>apple</b> after the > it returns false as I
expect and need but when I change the string to have <b>peach</b> after
the > instead of <b>apple</b> it still returns false and I need it to
return true. Without the bold tags it seems to work as I would expect. Any
ideas what I am doing wrong?