Get object at mouse position? (UI)

Hey guys, so I'm further working on an inventory system in my game and I've ran into a problem. Basically, what I want to do is when you are dragging an item and stop dragging it at a certain slot (an UI element), it detects which slot is at the current mouse position and performs a function to put the item there.

My current script is rather simple so far:

     public void OnBeginDrag()
     {
         ipos = this.transform.transform.Find("Icon").position;
         dragging = true;
         currentTooltip = "";
         sibling = this.transform.GetSiblingIndex ();
         this.transform.SetAsLastSibling ();
     }
 
     public void OnDrag()
     {
         tooltip = "";
         transform.transform.Find("Icon").position = Input.mousePosition;
     }
 
     public void OnEndDrag()
     {
         this.transform.transform.Find("Icon").position = ipos;
         ipos = Vector2.zero;
         dragging = false;
         this.transform.SetSiblingIndex (sibling);
     }

This is currently the script for the icon to snap back in place (as it doesn't hit a slot). How do I implement it to detect the slot the mouse points at? Thanks in advance.

Edit: Sorry, I mean detecting if the Icon transform is in the slot's bounds.