Forever Kept by Patricia D. Eddy

Her blood is unlike any other.
Dr. Riley Scott is dying. Heavy metal poisoning is slowly killing her.
Declan Bonney was turned more than three hundred years ago. He hates killing, so he allows groups to tour his castle—where he can take his pick of the unsuspecting for a quick snack.
When he sees Riley for the first time, he must taste her. Her blood is intoxicating, but it is her ability to resist his glamour that makes her truly beguiling.
Declan isn’t the only vampire hunting her, and when Riley’s taken, he will do anything to find her—and save her. Battling Hunters and enemy vampires is nothing new for Declan, but this time, he cannot fail. If he loses Riley, his very existence is over.