Contents lists available at ScienceDirect Sensors and Actuators B: Chemical journal homepage: www.elsevier.com/locate/snb Detecting Ocimene in mango using mustard oil based quartz crystal microbalance sensor Barnali Ghatak a, ⁎ , Sk Babar Ali b , Bipan Tudu a , Panchanan Pramanik c , Soumyo Mukherji d , Rajib Bandyopadhyay a,e a Department of Instrumentation and Electronics Engineering, Jadavpur University, Kolkata 700098, India b Department of Applied Electronics and Instrumentation Engineering, Future Institute of Engineering and Management, Kolkata 700 150, India c Department of Chemistry, GLA University, Mathura, Uttar Pradesh 281406, India d School of Biosciences and Bioengineering, IIT Bombay, Mumbai 400076, India e Laboratory of Artificial Sensory Systems, ITMO University, Saint Petersburg, Russia ARTICLE INFO Keywords: Ocimene Mustard oil Mango Quartz crystal microbalance Gas-chromatography mass spectrometry ABSTRACT A vegetable mustard (MUS) oil based quartz crystal microbalance (QCM) sensor has been developed to detect Ocimene (OCM), one of the significant flavor enhancing compounds in mango. After testing with all the vege- tables oils, MUS oil is found to be the most efficient with sensitivity factor of 0.276 Hz/ppm with satisfactory repeatability and reproducibility. The sensor exhibits a linear range of concentration (1–1000 ppm) with limit of detection of 1.04 ppm.The sensor is demonstrable in detecting the intended OCM with high selectivity from other dominant flavors involved in mango. The sensor can be used upto three months with minimum drift in frequency. Additionally, sensor response shows a good congruence with the GC–MS data with a correlation factor of 0.96. Further, the response of MUS-QCM sensor to the real mango samples has been found to be verifiable for quality assessment of most popular mango varieties viz. Alphonso, Gulabkhas, and Himsagar. 1. Introduction The worldwide recognition of mango (Mangifera indica L.) as a “king of fruits” among consumers is not only due to its aroma, flavor, and exotic taste, but also its significant contribution towards human health. [1–4]. India occupies the top position in total production among mango growing countries of the world accounting for 40.48% (18 million tones) production of mango and it [5]. Mainly, the relishable flavor characteristics of mango led to its high demand in both domestic and export markets, making it a product of increasing economic importance [6,7].One of the most significant flavor enhancer in mango, OCM be- longs to the monoterpene family, significantly contributing to the floral aroma in mango. Interestingly, OCM has a warm-herbaceous, green, terpene, citrus woody odor which is very diffusive with relatively low tenacity [8]. OCM is of immense therapeutic value due to its antiviral, antifungal, antiseptic, decongestant and antibacterial properties [9,10]. Additionally, OCM has been reported to be responsible for the green aroma of raw mangoes and especially to boost the flavor tone of mango [11–14]. The contribution of OCM aroma is found to be dominant in case of 14 different varieties of mango as reported by Pandit et al. [12]. Thus, the health benefits along with the qualitative characteristics of OCM can be attributed to the overall quality in mango. Numerous analytical methods have been reported for the detection and quantification of OCM in varieties of mango, illustrated in Table 1. All these reported works were based on gas-chromatography coupled to different detectors, viz. mass spectrometer, QP-5000, flame ionization detector [15–21]. Though by means of these analytical techniques, the results generated are of high precision and accuracy, but they are time consuming, expensive and require trained operators. Moreover, this technique cannot be adopted for small-scale industries in remote places. On the other hand, detection of some odoriferous terpene analytes viz. limonene, ϒ- terpinene and α- pinene has already been reported in few studies in which molecular imprinted polymer (MIP) based inter- digitated sensing platform has been demonstrated [22–30]. A recent study by our research group was on the development of poly-me- thacrylic acid imprinted QCM sensor for detecting 3-Carene; one of the signature volatiles in mango [31]. The QCM sensing platform has been successfully employed in another study where the crystal electrode was modified by gold nanoparticle embedded thiolate sensing film to detect the common volatile β- caryophyllene in mango [32]. However, https://doi.org/10.1016/j.snb.2018.12.156 Received 1 October 2018; Received in revised form 2 November 2018; Accepted 29 December 2018 ⁎ Corresponding author at: Department of Instrumentation and Electronics Engineering, Jadavpur University, Salt Lake Campus, Block LB, Sector III, Plot 8, Salt Lake, Kolkata, 700 098, India. E-mail address: barnali.099054@gmail.com (B. Ghatak). Sensors & Actuators: B. Chemical 284 (2019) 514–524 Available online 30 December 2018 0925-4005/ © 2018 Elsevier B.V. All rights reserved. T