The Department of Chemistry, Oakland University, Rochester, Michigan 48309, USA.
Anal Chem. 2011 Oct 15;83(20):7823-33. doi: 10.1021/ac201583c. Epub 2011 Sep 26.
An eight-sensor array coupling a chemoselective room-temperature ionic liquid (RTIL) with quartz crystal microbalance (QCM) transduction is presented in this work in order to demonstrate the power of this approach in differentiating closely related analytes in sensory devices. The underlying mechanism behind the specific sensory response was explored by (i) studying mass loading and viscoelasticity effects of the sensing layers, predominantly through variation in damping impedance, the combination of which determines the sensitivity; (ii) creation of a solvation model based on Abraham's solvation descriptors which reveals the fact that polarizability and lipophilicity are the main factors influencing the dissolution of gas analytes into the RTILs; and (iii) determination of enthalpy and entropy values for the studied interactions and comparison via a simulation model, which is also effective for pattern discrimination, in order to establish a foundation for the analytical scientist as well as inspiration for synthetic pathways and innovative research into next-generation sensory approaches. The reported sensors displayed an excellent sensitivity with detection limit of <0.2%, fast response and recovery, and a workable temperature range of 27-55 °C and even higher. Linear discriminant analysis (LDA) showed a discrimination accuracy of 86-92% for nitromethane and 1-ethyl-2-nitrobenzene, 71% for different mixtures of nitromethane, and 100% for these analytes when thermodynamic parameters were used as input data. We envisage applications to detecting other nitroaromatics and security-related gas targets, and high-temperature or real-time situations where manual access is restricted, opening up new horizons in chemical sensing.
本文展示了一种由八个传感器组成的阵列，该阵列将化学选择性室温离子液体（RTIL）与石英晶体微天平（QCM）换能器相结合，以证明这种方法在感测器件中区分密切相关分析物的能力。通过（i）研究传感层的质量负载和粘弹性效应，主要通过阻尼阻抗的变化来研究，这两者的结合决定了灵敏度；（ii）创建基于 Abraham 溶剂化描述符的溶剂化模型，揭示了极化率和疏水性是影响气体分析物溶解到 RTIL 中的主要因素这一事实；以及（iii）确定研究相互作用的焓和熵值，并通过模拟模型进行比较，该模型也可用于模式识别，为分析科学家奠定基础，并为合成途径和下一代感测方法的创新研究提供灵感。所报道的传感器具有出色的灵敏度，检测限<0.2%，响应和恢复迅速，工作温度范围为 27-55°C，甚至更高。线性判别分析（LDA）显示，对于硝基甲烷和 1-乙基-2-硝基苯，其区分准确率为 86-92%，对于不同比例的硝基甲烷混合物，其区分准确率为 71%，而当热力学参数用作输入数据时，这些分析物的准确率为 100%。我们预计该传感器可用于检测其他硝基芳烃和与安全相关的气体目标，以及在手动访问受限的高温或实时情况下，为化学感测开辟新的视野。
