Development of nano-material based optical chemical sensors indicating oxygen levels in petrochemistry related workplaces

In workplaces, especially in refineries, volatile petroleum solvents are usually in the form of mixtures of alkanes, cyclic alkanes, alkenes and the aromatics. Such atmospheres which are deficient in oxygen may not provide adequate sensory warning of danger. Therefore correct and continuous monitoring of oxygen levels in such environments is quite important. On the other hand, ruthenium (II) derivatives are known as oxygen sensitive dyes and have intensively been used in the design of optical chemical sensors. Most of the ruthenium dyes suffer from leaching from host matrices due to the water solubilities. In order to provide the best host/dye compatibility we used the amphiphilic ruthenium derivatives in silicon based matrices. In this work, emission-based oxygen sensing properties of highly luminescent ruthenium (II) derivatives were tested in the presence and absence of some volatile organics. Newly synthesized two orange-red emitting alkyl branched ruthenium complexes were used along with silver nanoparticles (AgNPs) in two different silicon based matrices for oxygen sensing purposes. The sensing materials were fabricated in form of thin films and electrospun nanofibers. Ionic liquid and perfluorinated compounds were exploited as additives to enhance the response to oxygen. Oxygen induced spectral changes at 630 nm were followed for both gas phase and dissolved oxygen as the analytical signal. The oxygen sensitivities of the probes were also tested by lifetime based and kinetic mode measurements. Utilization of the amphiphilic Ru dyes in silicon along with AgNPs in the form of electrospun fibers resulted in many advantages such as enhanced long term stability, increased surface area, sensitivity and improvement in all sensor dynamics. Sensing characteristics of the offered design were tested and calibrated in the presence of vapors of benzene, toluene, ethylbenzene, hexane and xylene, which simulate refinery related work places.