I have this code and it works more or less, the problem is some of them are empty and in wrong place in the array, and inside offers there's 3 other itemprops.
I dont want to hard code because I'm going to use it on multi websites.
function get_product_itemprop($url){
$url = file_get_contents($url);
$d = new DOMDocument();
$d->loadHTML($url);
$xpath = new DOMXPath($d);
$nodes = $xpath->query('//*[@itemprop]'); 
$new_data = array();
foreach ($nodes as $node) { 
    $new_data[$node->getAttribute("itemprop")] = trim(preg_replace('/\s+/', ' ',$node->nodeValue));
}
return $new_data;
}
Result of the function
    array(8) {
  ["breadcrumb"]=>
  string(38) "Home Atomizers & Coils Amor Mini coils"
  ["name"]=>
  string(15) "Amor Mini coils"
  ["sku"]=>
  string(5) "CO815"
  ["offers"]=>
  string(8) "$ 13.99"
  ["price"]=>
  string(0) ""
  ["priceCurrency"]=>
  string(0) ""
  ["availability"]=>
  string(0) ""
  ["url"]=>
  string(0) ""
  }
On http://search.google.com/structured-data/testing-tool I get all the itemprops and I want a similar structure they done but with an array:

                        
You can iterate the
attributesproperty:Example
Output
The sample code fetches all elements in the document having
itempropproperty. If you want to fetch all elements with properties, use@*, e.g.//*[@*].