If you're a working parent, it's more than likely that you spend most of your time wracked with guilt. But there's no point in eating yourself up with guilt. Try these ways of making sure that your limited spare time is used in a way which will benefit you all.
Everyday routines can equal quality time.
Just because you don't spend all day, everyday, with your children, doesn't mean that you have to be a one-person circus act when you DO get to see them. You can teach them a valuable lesson about the importance of working for what you want from life, when you show them that you're a human being, not Supermom. You don't have to then embark on a range of energetic activities to prove to your children that you love them. It's a good idea to get into a regular routine during the week, where everyone spends some quiet time debriefing after the day's events, and reconnecting as a family. Allocate your children some of the cooking tasks, or get them to set the table or put away that laundry which get folded on the weekend.