I want to separate from my husband of 14 years in Pa. and go live in another state(Md.) with my 11 year old daughter. Is it true I can't take my daughter with me out of state?

It may be. The child is your husband's as well. He is may be entitled to joint custody and visitation. That could prevent you from taking her out of state.

I want to separate from my husband of 14 years in Pa. and go live in another state(Md.) with my 11 year old daughter. Is it true I can't take my daughter with me out of state?
Yes and no.
Under Pennsylvania law, parents who relocate their children without the consent of the noncustodial parent can face abduction charges.
A parent with primary physical custody who wishes to relocate her child must file a relocation petition.
Parents wishing to relocate their child from Pennsylvania to another state have one consideration: distance. Distances of more than 50 or 70 miles may require that custodial parents file a relocation petition, especially if the distance would present a hardship for the noncustodial parent to have a relationship with the child

Family Law (Divorce, Family Relations): Move out of state?, pennsylvania laws, custodial time (http://en.allexperts.com/q/Family-Law-Divorce-920/Move-state.htm)