## 1 Introduction  
Terpenes are hydrocarbons released into environment from herbaceous vegetation. These biogenic volatile compounds, which include monoterenes, sesquiterpenes and oxygenated terpenes [1], affect the global radiation balance due to the vigorous reactions of their oxidative products with ozone and OH in the troposphere [2]. On the other hand these terpen are responsible for the characteristic whiff and fragrance in plants and are very important candidates from the sensing point of view. It is vital to investigate freshness, shelf-life and usability of these plants because many terpenes emanate from herbs used in fresh and dried form as spices and flavoring agents in food processing. This sensing is also essential for human health [3], as well as for atmospheric [4] and environmental [5] concerns. Human thresholds for odor, nasal pungency, nasal localization, and eye irritation to some of the selected terpenes, which enhance the need of highly sensitive and selective methods for quantification of these compounds, have been described by [PERSON] _et al._[6]. Generally, these analytes are extracted, pre-concentrated, and analyzed by gas chromatography/mass spectrometry (GC-MS) [7], gas chromatography flame ionization detection (GC-FID) [8], accelerated solvent extraction (ASE) GC-MS [9], solid-phase microextraction (SPME) GC-MS, GC-FID [10] and automated thermal desorption (ATD) GC-MS [11]. However, these methods are quite expensive and require expert trained personnel. A favorable solution to this problem might be to identify some characteristic ingredients which will give a hint for the quality of the herbs. A simple analytical technique is desirable in order to provide on-line detection. Arrays of chemical sensors based on multichannel quartz crystal microbalances (QCM) _i.e._, electronic noses [12,13] and tongues [14,15] are a quite suitable option for continuous and online monitoring in this scenario. Sensor arrays can be designed considering two aspects: firstly, sensing materials need to be low cost, facile to synthesize, stable, and highly sensitive as well as selective. Secondly, transducer elements should be sensitive to minute fluctuations of analyte concentrations and being portable and rapid in response. To address first issue, artificial recognition materials generated via molecular imprinting [16] provide highly efficient applications in sensor architecture that mimic the capabilities of biological noses and can still overcome the inherent limitations of their natural counterparts, especially poor chemical and thermal stability. Molecularly imprinted polymers (MIPs), one of the most promising recognition materials for e-nose, have been applied since their first introduction [17] as highly selective coatings with excellent binding efficiency of analyte molecules. Polymers are synthesized in the presence of analytes acting as templates. High cross-linking will guarantee sufficient stiff cavities for selective analyte inclusion. With this approach, even isomers can be distinguished with sufficient selectivity. QCM represents a kind of transducer which exploits the benefits of MIPs without label-free detection [18]. Mass loading of QCM is visualized by frequency shift which can be monitored by an oscillator circuit. This kind of measurement shows a universal applicability, robustness, portability and high sensitivity. Usually, a wide linear range of sensor responses can be observed. Thus, MIP-QCM sensor arrays [18] can be used for a large variety of analytical problems of interest. Some attempts [19,20] have already been made in order to detect terpenes in herbs using MIP-based QCM, and selectivity has been identified as the most important challenge in this field. During the course of this investigation we developed QCMs with six channels, coated with MIPs for continuous and online monitoring of terpenes emanated from fresh and dried species of the Lamiaceae family _i.e._, rosemary (_Rosmarinus Officinalis L_), basil (_Ocimum Basilicum_) and sage (_Salvia officinalis_).