eta1-Allypalladium complexes with tridentate PNP’ ligand for the assembly of modified Screen Printed Electrodes: an electrochemical study.

Specific Pd-based organometallic complex, in particular the [Pd(η1-CH2–CH=CH2)(P–N–P’)]BF4 was used for the assembly of chemically modified Screen Printed Electrodes (SPEs) and their electrochemical reactivity was also investigated. For this purpose potassium ferricyanide, hexaammineruthenium(III) chloride, sodium hexachloroiridate-(III) hydrate, ascorbic acid (AA), uric acid (UA), acetaminophen (Ac), guanine (G) and adenine (A) were used to study the electron-transfer processes, which occurred at modified SPEs, fabricated by using the [Pd(η1-CH2–CH=CH2)(P–N–P’)]BF4, applying the drop casting procedure. Interesting results were obtained in the case of the guanine (G) quantitative detection, especially in terms of a wide range of concentration (2.5-40 nM), an high sensitivity (of 49.0 A M-1 cm-2), a low detection limit (L.O.D.= 1.0nM) and a fast response time (of t=2s). The intra-electrode reproducibility (RSD%) was <1% for the same SPE used for each point of the calibration plot. The inter-electrode reproducibility (RSD%), estimated by using different SPEs for each single point of the quantitative calibration graph, ranging from 5 to 10%, better than that exhibited by other different chemical sensors, described in literature, and reported in this work for comparison. In addition, the high selectivity of the chemically modified sensors toward the oxidation of guanine, exhibited in presence of a mixture of nucleic acids (G + A, in the same electrochemical bath solution) could be related to the different electro-catalytic mechanisms, as demonstrated by the XPS study. This chemical sensor prototype could be very promising for bio-medicine applications, as the early detection of some kind of cancer diseases.