I'm not sure about that- I just know that a lot of kiddos get bad rashes with synthetic fabrics. And I'm talking like...horrible rash with pustules that looked like pimples, it was really terrible! I stripped my diapers several times and changed detergents and nothing else helped, so I had to conclude it was the fabrics.
I have used original Tide, Charlie's, All free & clear, Arm & Hammer sensitive/free & clear?, and I think 7th generation as well.
I really like Charlie's powder, it cleaned the heck out of my washing machine the first time I used it I was like holy crap dude! I never had stink issues or buildup when I used it and I felt like it got everything super clean.