ISOLUTE® C18 is a retentive, non-polar sorbent for extraction of a range of analytes from aqueous samples using a non-polar retention mechanism. ISOLUTE® C18 is the most commonly used C18 sorbent for the extraction of acidic, neutral and basic compounds from aqueous sample matrices. Secondary silanol interactions can be exploited to enhance extract purity and method robustness for basic analytes. It is available in a wide range of SPE columns and 96-well plate formats.