The present invention is directed to a sensing device including a plurality of capacitive sensors, each capacitive sensor comprises a sensing element electrically connected to electrodes and comprising carbon dots; the plurality of capacitive sensors comprises at least a first sensor, a second sensor and a third sensor; the carbon dots of the first sensor, the second sensor and the third sensor independently comprise hydrophilic surface groups, each independently comprising nitrogen and oxygen atoms; the hydrophilic surface groups of the carbon dots predetermine: (i) a different surface polarity; and (ii) a different sensitivity of the first sensor of the second sensor and of the third sensor to a volatile compound (VC). Further provided is a method of using the sensing device of the invention, such as for determining the presence of a microorganism of interest in a sample or at a target location.

A process for determining the viability of a biological indicator includes exposing the biological indicator to a viability detection medium, the biological indicator including test microorganisms, the exposing the biological indicator to the viability detection medium producing a gaseous reaction product when one or more of the test microorganisms are viable. The presence or absence of the gaseous reaction product produced by the biological indicator combined with the viability detection medium is detected with a sensing device, the sensing device comprising a capacitive sensor, an electro-mechanical sensor, or a resistive sensor, wherein the presence of the gaseous reaction product indicates the presence of viable test microorganisms and the absence of the gaseous reaction product indicates the absence of viable test microorganisms. A sterilization detection device includes a container configured to contain the biological indicator, a viability detection medium, and the sensing device.

Provided is a process for the quantification and determination of the stable fraction of carbon in a sample of pyrolyzed carbon in anoxic storage. The process comprises pyrolyzing an organic material and measuring the carbon content of a sample of pyrolyzed carbon. A sample of the pyrolyzed carbon is sealed in a vial in an oxygen-free atmosphere, and a mixture of nutrients and microbes is added thereto. The temperature of the vial is controlled. The volume and species of gases evolved over time is measured. The fraction of carbon lost is calculated based on the gases evolved, the carbon content and mass relative to a control sample.