Using plastic turkey baster or something small where the chemicals are exposed for just a few minutes is fine. But leaving a chemical in a plastic jug over a long period of time is not. Remember the half gallon to gallon of liquid you are working with will be taken down to about a teaspoon of final product so anything that liquid absorbs while it might be a very small percentage it will be concentrated considerably when you are at the final stage. I know there was research done on even the most stable plastics in baby bottles and it was found that still chemicals leeched into the milk. There was a craze for a while for glass baby bottles.

I am no chemist. But I know common sense and I know glass wont leech anything. You can go to the grocery store and but a gallon glass jug of some type of juice and use that but I wouldnt use plastic for anything.