Speciation of lead compounds in fish by capillary electrophoresis-inductively coupled plasma mass spectrometry

A capillary electrophoresis-inductively coupled plasma mass spectrometric (CE-ICP-MS) method for lead speciation application is described. Sample containing ionic lead compounds were subjected to electrophoretic separation before injection into the micro-concentric nebulizer (CEI-100). The species studied include inorganic lead (Pb-II), trimethyl lead (TML) and triethyl lead (TEL). The separation has been achieved on a 70 cm length x 75 mu m id fused silica capillary. The electrophoretic buffer used is 15 mmol l(-1) Tris ( pH 8.25) containing 10 mmol l(-1) SDS ( sodium dodecyl sulfate), 0.2 mmol l(-1) EDTA and 2% v/v methanol, while the applied voltage is set at +26 kV. The lead species in biological tissues are extracted into 1% m/v EDTA solution taken in a closed centrifuge tube and kept on a water bath, using microwaves at 70 degrees C for 10 min. The extraction efficiencies of individual lead species added to the sample at 2 mu g Pb g(-1) level are between 97% and 102%. The detection limits of the species studied are in the range 0.2 - 0.6 ng Pb ml(-1). The procedure has been applied for the speciation analysis of two reference materials namely dogfish liver tissue (NRCC DOLT-3) and oyster tissue (NIST SRM 1566a) and two real-world samples.