Class specific discrimination of volatile organic compounds using a quartz crystal microbalance based multisensor array

Abstract

The use of quartz crystal microbalance (QCM) sensor arrays for analyses of volatile organic compounds (VOC) has attracted significant interest in recent years. In this regard, a group of uniformed materials based on organic salts (GUMBOS) has proven to be promising recognition elements in QCM based sensor arrays due to diverse properties afforded by this class of tunable materials. Herein, we examine the application of four novel phthalocyanine based GUMBOS as recognition elements for VOC sensing using a QCM based multisensor array (MSA). These synthesized GUMBOS are composed of copper (II) phthalocyaninetetrasulfonate (CuPcS) anions coupled with ammonium or phosphonium cations respectively (tetrabutylammonium (TBA), tetrabutylphosphonium (P), 3-(dodecyldimethyl-ammonio)propanesulfonate (DDMA), and tributyl-n-octylphosphonium (P)). These materials were characterized using ESI-MS and FTIR, while thermal properties were investigated using TGA. Vapor sensing properties of these GUMBOS towards a set of common VOCs at three sample flow rate ratios were examined. Upon exposure to VOCs, each sensor generated analyte specific response patterns that were recorded and analyzed using principal component and discriminant analyses. Use of this MSA allowed discrimination of analytes into different functional group classes (alcohols, chlorohydrocarbons, aromatic hydrocarbons, and hydrocarbons) with 98.6% accuracy. Evaluation of these results provides further insight into the use of phthalocyanine GUMBOS as recognition elements for QCM-based MSAs for VOC discrimination.

Bulk and Surface Acoustic Wave Sensor Arrays for Multi-Analyte Detection: A Review

“…Table 1 summarizes commercially available acoustic sensor arrays utilizing QCMs. They are mainly designed for liquid applications, but they can also be used for gaseous samples if an appropriate sampling unit is provided as shown, for instance, for the QSense system from Biolin Scientific [25]. All arrays use the resonance frequency as signal response; many include the dissipation values.…”

“…GUMBOS compounds based on metallophthalocyanine tetrasulfonate were applied on the QCM sensors of a four-channel array (Biolin Scientific; see Table 1). The array allowed sufficient discrimination between ten different VOCs into the corresponding functional group classes (alcohols, aromatic and aliphatic hydrocarbons, and chlorinated hydrocarbons), which was promising for applications in food quality control [25]. An array of eight QCM sensors coated with different ionic liquids was applied to detect three explosives including methane and two aromatic nitro compounds.…”

Quartz Crystal Microbalance Based Sensor Arrays for Detection and Discrimination of VOCs Using Phosphonium Ionic Liquid Composites

“…Subsequently, a vial containing the VOC of choice was bubbled with argon to generate a sample of equilibrated headspace. The analyte and carrier channels merged to allow dilution of the analyte flow to yield respective flow rate ratios [26]. The total flow rate was held constant at 100 sccm by using digital mass flow controllers.…”

A Langasite Crystal Microbalance Coated with Graphene Oxide-Platinum Nanocomposite as a Volatile Organic Compound Sensor: Detection and Discrimination Characteristics

“…Various methods have been adopted to achieve selectivity in a gas sensor [3][4][5][6]. A sensor array in which each sensor is coated with a distinct sensing material has been demonstrated for gas selectivity [3]. The sensors in the array would respond with the highest sensitivity towards specific analyte gases depending on the affinity of the individual sensing medium employed for selectivity to gases.…”

“…Each of the independent response variables tracks the distinct perturbations in the characteristics of the sensing layer including the physical, electrical, and chemical properties. By statistically analyzing the individual responses of the sensor array and the independent response variables of the multivariable transducer, the information on gas selectivity can be unraveled [3,8].…”