Thank you very much for the advice. Is it possible the ZnCl2 could go bad after a long time? The bottle is ancient... not sure when it was purchased as I joined this lab group only recently and the PI changed as well so he doesn't know. I'm only wondering since my purification didn't do anything.
Commercial ZnCl2 in solid form varies from batch to batch. If I was unable to buy it fresh, I took "anhydrous" ZnCl2 off the shelf, placed it into a 100 mL round bottom flask, and then melted it under high vacuum. You have to be careful not to melt the flask. This is known as the "fusion method of preparing anhydrous zinc chloride".
If you only need to use it once, this method works. If you need to do it over and over, depending upon how much ZnCl2 you need, perhaps you can make a THF solution of known concentration.
Good luck!