QCM virtual sensor array: Vapor identification and molecular weight approximation

Abstract

Herein, we present a promising approach for simultaneous identification and molecular weight approximation of closely related pure organic vapors using the quartz crystal microbalance (QCM). In this regard, a QCM virtual sensor array (VSA) was fabricated employing a binary blend of ionic liquid and polymer, i.e. 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HMIm][NTf2]) and poly(methyl methacrylate). This VSA technique allows discrimination/identification of closely related alcohols including isomers, while use of a composite coating facilitates molecular weight approximation of this set employing only the first harmonic. Statistical analyses (principal component and discriminant analyses) allowed identification of all analytes with extremely high accuracy. Molecular weight approximations were achieved with a linear correlation of R2≈0.99. This is the first report of a QCM sensor array that allows both identification and molecular weight approximation of organic vapors.