A recognizable response pattern is produced by conventional electronic noses (eNoses) using a wide range of dissimilar but not specific chemical sensors. For some time, electronic noses gained popularity with developers of artificial intelligence algorithms and neural networks. However, physical sensors have limited performance due to physical instability and overlapping responses. The chemistry of aromas cannot be quantified or separated by eNoses.

zNose®, a new type of electronic nose, is based upon ultra-fast gas chromatography and simulates an almost unlimited number of specific virtual chemical sensors. This new electronic nose produces olfactory images based upon aroma chemistry.

The zNose® is capable of performing analytical measurements of volatile organic vapors and odors in near real time with part-per-trillion sensitivity. It takes only seconds to separate and quantify the individual chemicals within an odor. Electronically variable sensitivity, universal non-polar selectivity, and picogram sensitivity are achieved using a patented solid-state mass-sensitive detector. The instrument measures vapor concentrations spanning 6+ orders of magnitude with the help of an integrated vapor preconcentrator coupled with the electronically variable detector.

In this article, a portable zNose® (Figure 1) is shown to be a useful environmental tool for quantifying the concentration of phenol in air and water samples.

Read more: Detecting Phenol in Water and Air Using a Gas Chromatography-Based Electronic Nose