Montagut Y J, García J V, Jiménez Y, March C, Montoya A, Arnau A
Grupo de Fenómenos Ondulatorios, Departamento de Ingeniería Electrónica, Universitat Politècnica de València, Spain.
Rev Sci Instrum. 2011 Jun;82(6):064702. doi: 10.1063/1.3598340.
The improvement of sensitivity in quartz crystal microbalance (QCM) applications has been addressed in the last decades by increasing the sensor fundamental frequency, following the increment of the frequency/mass sensitivity with the square of frequency predicted by Sauerbrey. However, this sensitivity improvement has not been completely transferred in terms of resolution. The decrease of frequency stability due to the increase of the phase noise, particularly in oscillators, made impossible to reach the expected resolution. A new concept of sensor characterization at constant frequency has been recently proposed. The validation of the new concept is presented in this work. An immunosensor application for the detection of a low molecular weight contaminant, the insecticide carbaryl, has been chosen for the validation. An, in principle, improved version of a balanced-bridge oscillator is validated for its use in liquids, and applied for the frequency shift characterization of the QCM immunosensor application. The classical frequency shift characterization is compared with the new phase-shift characterization concept and system proposed.
在过去几十年中，通过提高传感器的基频来解决石英晶体微天平（QCM）应用中灵敏度的提升问题，这是按照绍尔布雷预测的频率/质量灵敏度与频率平方成正比的关系来进行的。然而，这种灵敏度的提升在分辨率方面并未完全实现。由于相位噪声增加导致频率稳定性下降，特别是在振荡器中，使得无法达到预期的分辨率。最近提出了一种在恒定频率下进行传感器表征的新概念。本文展示了对这一新概念的验证。选择了一种用于检测低分子量污染物西维因（一种杀虫剂）的免疫传感器应用来进行验证。原则上，一种改进版的平衡桥振荡器在液体中的使用得到了验证，并应用于QCM免疫传感器应用的频移表征。将经典的频移表征与新提出的相移表征概念和系统进行了比较。
