Chemical detectors and sensors design via molecular simulation
Detection or sensing of various compounds is a key technology for the industrial, manufacturing, business and virtually any sector one can imagine. In order to improve safety and efficiency of processes whether these are the manufacturing of plastic cups or the indoors living of a family, one has to be able to monitor harmful agents at very low concentrations with accuracy, repeatability and affordable cost.
Sensors and detectors follow some principles:
- They can react with the detected species and produce a comprehensive change of property
- They can adsorb the detected species and produce a change of property
In both cases, a change in property is required. That property can be a visual one like color or spectrum, an electronic one, a physical one or a chemical one. The translation of that property to human understanding is the second step.
When a reaction is carried out, one [or more] compounds is being formed. That compound has a new set of properties that can be used. The same [but at a lower extend] happens with adsorption of species. Optimum design thus should focus on:
- Finding a property change that can be perceived or made perceivable by the human [or electronic] eye
- Finding a ‘detection limit’ below which detection is not feasible. For example even the greatest color change cannot be seen if the concentration of the detected species is low; imagine a drop of red color in a lake of blue – no change will be evident
This is where molecular simulation comes in the game; using molecular simulation one can identify:
- All properties changes between initial and final systems
- Detection limits
- Optimum matches as detectors/ sensors
In a related project of ours we had to identify the optimum detectors for specific organic molecules that were the secretions of bugs [and thus identify bugs presence]. In this work we had to identify the greatest changes between the initial detector [Ionic Liquid] and the adsorbed system [Ionic Liquid plus species]. Polarizability, Refractivity and LogP were recorded for 500 Ionic Liquids vs our species in various concentrations of species, down to ppm. Top three polarizability changes have taken their way to the lab in order to become the next detectors of these organic compounds!