Miniaturized Gas Chromatographic Nose for On-Site Adulteration Detection

Miniaturized gas chromatographs (mu GCs) have been applied to a diverse set of applications bringing their analytical capabilities to the field and point-of-care solutions. This work presents, for the first time, the use of a mu GC for the rapid detection of fuel adulteration using pattern recognition techniques. The new mu GC which weighs around 2 kg and has dimensions of 25 x 22 x 15 cm houses two 1-m-long semipacked columns fabricated using microelectromechanical systems (MEMS) technology and utilizes two commercial miniature photoionization detectors (PI-Ds). The columns are coated with two different ionic liquids as their stationary phases. All the electrical and fluidic components are controlled by stackable, modular electronics specifically designed and implemented for multichannel mu GCs. The current electronics can support six valves/pumps, four microcolumns/micropreconcentrators with temperature programming, and five commercial PI-Ds. The modular electronics is designed to be expandable and to accommodate the integration of more GC columns, enabling more complex analysis. The efficiency of this portable GC nose is demonstrated by discriminating between a pure diesel sample and the one altered by adding 10% kerosene. Without the need for full chromatographic separation, the patterns generated by the two columns were able to identify all the samples accurately. This portable GC nose can be used in a wide variety of applications in which a binary response is needed for rapid screening.