Pharmaceutical electrochemistry: the electrochemical detection of aspirin utilising screen printed graphene electrodes as sensors platforms.

A sensitive electrochemical sensor was designed for acetyl salicylic acid detection using graphene modified Screen Printed Electrodes. The electrochemical response of the sensor with graphene was improved compared to Screen Printed Electrodes without graphene and displayed an excellent analytical performance for the detection of acetyl salicylic acid. The high acetyl salicylic acid loading capacity on the electrode surface and the outstanding electric conductivity of graphene were also discussed in this manuscript. When a range of different concentrations of acetyl salicylic acid from 0.1 to 100 μM into a pH 4 buffer solution (N defined as the sample size N = 9) were plotted against the oxidation peak a linear response was observed. The detection limit was found to be 0.09 μM based on (3-σ/slope). Screen Printed Graphene electrodes sensors methodology is shown to be useful for quantifying low levels of acetyl salicylic acid in a buffer solution as well as in biological matrixes such as human oral fluid. A linear response was obtained over a range of concentrations from 10 to 150 μM into a human oral fluid solution (N = 10) giving a detection limit of 8.7 μM

Mineral–fluid interactions in the late Archean Closepet granite batholith, Dharwar Craton, southern India

International audienceThe chemical composition of different rocks as well as volatile-bearing and volatile-free mineralshas been used to assess the presence of fluids in the Closepet batholith and to estimate the intensity ofthe fluid−rock interactions. The data were processed using polytopic vector analysis (PVA). Additional datainclude measurements of water content in the structure of volatile-free minerals and an examination of growthtextures. The composition of mineral domains indicated formation/transformation processes with commonfluid−mineral interactions. In general, the results suggested that the processes occurred in a ternary system.Two end-members were likely magmas and the third was enriched in fluids. In contrast, analysis of the apatitedomains indicated that they likely formed/transformed in a more complex, four-component system. This systemwas fluid-rich and included hybrid magma with a large mafic component. PVA implies that the fluids do notappear to come from one source, given their close affinity and partial association with mantle-derived fluids. Adynamic tectonic setting promoting heat influx and redistribution, and interaction of fluids suggests that the formation/transformation processes of minerals and rocks occurred in a hot-spot like environment