Surface Pretreatment Boosts the Performance of Supramolecular Affinity Materials on Quartz Crystal Microbalances for Sensor Applications

Abstract

A Teflon-like coating is the key for the boost in sensitivity of quartz microbalances for the tracing of airborne analytes. Since the undesired signals for the interfering compounds are suppressed and the ones for the targeted compounds (e.g., peroxide explosives) are enhanced, the PCA output is improved.

Microporous Triptycene‐Based Affinity Materials on Quartz Crystal Microbalances for Tracing of Illicit Compounds

“…To determine the affinity of OMIMs 1–5 for different analytes, we used 195 MHz high‐fundamental frequency quartz crystal microbalances (HFF‐QCMs) with aluminum electrodes. These QCMs were pre‐coated with a passivating perfluorinated layer . The affinity materials were then coated by a highly reproducible electro‐spray protocol, allowing a well‐controlled deposition of 10.4 ng (50 kHz of Δ f ) onto the individual QCMs .…”

“…These QCMs were pre-coated with a passivating perfluorinated layer. [26] The affinity materials were then coated by a highly reproducible electro-spray protocol, allowing a well-controlled deposition of 10.4 ng (50 kHz of Δf) onto the individual QCMs. [27] HFF-QCMs offer the advantage of improved detection limits and short response times compared to QCMs with lower resonance frequency.…”

Synthesis of 9,9′‐Spirobifluorenes and 4,5‐Diaza‐9,9′‐spirobifluorenes and Their Application as Affinity Materials for Quartz Crystal Microbalances

“…[7] Moreover, the design of functional groups that enable hydrogen [14b] or halogen bonding [29] favor the specific affinity towards ad esired analyte. [30] Therefore, with this setup, the selectivity towards other ubiquitous vapors can be significantly improved, relative to most inorganic sensor materials. [28] Ap recoating of 1 H,1 H,2 H,2 H-perfluorooctylphosphonic acid on the electrode of the QCMs uppresses interferinga nalyte signals, whereas the targeted analytes showe nhanced signals.…”

An Overview of High Frequency Acoustic Sensors—QCMs, SAWs and FBARs—Chemical and Biochemical Applications

“…In another report [165], they developed 200 MHz QCM device coated with modified dendrimeric structures for online detection of triacetone triperoxide (TATP) i.e., an explosive. With such a high resonance frequency, a detection limit of 1 ppm for TATP was achieved with suitable response/recovery times i.e., <5 s. In order to enhance selectivity by reducing the non-specific interactions, the authors [166] modified HFF-QCM electrode surface with alkylated phosphonic acids and corresponding partially fluorinated phosphonic acid groups. The interesting aspect of these modifications is their hydrophobic and lipophobic properties as it resulted in a 55% reduced frequency shifts for water and 74% for cyclohexane, respectively.…”

“…( A ) PCA result of HFF-QCM sensor array for the detection of TATP without pretreatment, ( B ) PCA result of HFF-QCM sensor array for the detection of TATP after surface pretreatment, indicating that surface treatment resulted an improved TATP detection with better separation from interferents, adapted with permission from [166]. …”