Electrochemical detection of heavy metals in rice, milk and tap water using free-standing carbon felt electrodes.

In this work, a carbon felt (CF) was utilized to fabricate electrochemical sensors for the simultaneous detection of Cd, Pb and Hg. The working conditions of CF sensors including thermal activation, electrolytes, and enrichment potentials and times were systematically investigated. Under the optimal detection conditions, the resulting sensors showed good linearity in the concentration ranges of 3-10,000, 2-10,000 and 5-10,000 μg/L for the detection of Cd, Pb and Hg, corresponding to the detection limits of 1, 0.5, and 1 μg/L, respectively. Meanwhile, the resulting electrochemical sensor demonstrates excellent reproducibility and anti-interference. In addition, the CF electrodes maintain good stability even after 180 days of storage at room temperature. In real water, rice and milk samples, the CF electrodes have been successfully utilized for the detection of Cd, Pb and Hg and the results were in agreement with those obtained from the inductively coupled plasma mass spectrometry.