Abstract
Oven and hot plate leach methods were compared with the official AOAC room temperature method for leaching Pb and Cd from specially glazed ceramic cookware. The hot leach methods released from 7 to 11 times more Pb and from 6 to 10 times more Cd after 24 h than did the AOAC procedure. Both hot leach methods specify a 2 h treatment with boiling 4% acetic acid, followed by 22 h of cooling at room temperature. The results show that essentially all of the Pb and Cd are released within 2 h, suggesting that the total contact time can be limited to 2 h to save laboratory space and time. The hot plate method is less difficult to perform and results in a continuous refluxing action. For these reasons, it is proposed as the hot leach method of choice.