Determination of Lead in Oral Squamous Cell Carcinoma Tissue by New Potentiometric Sensor based on [2-{4-(Diphenylphosphanyl) Phen-2-Yl} Pyrimidin-4-Yl]-3-(Triethoxysilyl) Prop-1-Yl Urea

Inorganic lead compounds have recently been classified as human carcinogens by the International Agency for Research on Cancer (IARC). In this light and given the capability of ion-selective electrodes for potentiometric measurements of heavy metal ions, a novel lead ion membrane electrode was prepared based on a novel synthesized compound and was used for the determination of lead content in oral squamous cell carcinoma tissues. The selectivity of the electrode response to lead ions was good in the presence of many commonly occurring interfering species such as alkali, alkaline earth, transition, and other heavy metal ions, as further reflected by conductance studies. The optimal membrane composition was 7 % wt. of the ion carrier, 30 % wt. of PVC powder, 60 % wt. of NPOE, and 3% wt. KTCPB. The response of the sensor was linear in the concentration window of 1.0x10(-7) to 1.0x10(-1) M with a detection limit of 8.5x10(-8) M, and the slope of the calibration plot was determined to be 29.4 +/- 0.3 mV per decade of concentration. The electrode response was pH-independent in the wide range of 2.2-8.9, and it offered merits of quick response, further to its low detection limit, selectivity profile, and broad linear response range. The sensor showed a fairly fast response of similar to 30 s and could be reliably used for over 4 months. The membrane electrode was used in the determination of Pb2+ concentration in healthy and cancerous oral tissues.