Hi, first off all, I know this isn´t the best forum for my questions about HPLC columns, but unfortunately on other forums either people don´t answer or don´t know what they are talking about. So here my question: I have to separate enantiomer proteins with HPLC columns. I read it is import which filter paper I used before so I´ll post it,too: Whatman filter paper grade 43 So far so good. my problem now is that I need contaminations about nearly zero percent. Therefore I´m using at the moment a HPLC column of Chiral. but all the time I get peaks that shouldn´t be there. Would it be better to change the manufacturer to Waters or Agilent?