An investigation into possible sources of phthalate contamination in the environmental analytical laboratory

A study of common laboratory equipment and components was performed in order to identify sources of contamination of phthalates prior to testing environmental samples for such compounds. A screening study revealed significant leaching from laboratory consumables, such as plastic syringes, pipette tips released maximum leachings of 0.36 mu g cm(-2) diethylhexyl phthalate (DEHP) and 0.86 mu g cm(-2) diisononyl phthalate (DINP), plastic filter holders produced maximum leachings of 2.49 mu g cm(-2) dibutyl phthalate (DBP) from polytetrafluoroethylene (PTFE); specifically 0.61 mu g cm(-2) DBP from regenerated cellulose and 5.85 mu g cm(-2) dimethyl phthalate (DMP) from cellulose acetate and Parafilm(R) leached levels up to 0.50 mu g cm(-2) DEHP. In addition, a high-temperature bake-out process was found necessary to eliminate quite high levels of two phthalates present in a commercial bulking agent for pressurized liquid extraction.