An in-line device for measuring the water content in ethanol was developed using a polyvinyl alcohol (PVA)-coated quartz crystal microbalance. Bio-ethanol is widely used as the replacement of gasoline, and its water content is a key component of its specifications. When the PVA-coated quartz crystal microbalance is contacted with ethanol containing a small amount of water, the water is absorbed into the PVA increasing the load on the microbalance surface to cause a frequency drop. The determination performance of the PVA-coated microbalance is examined by measuring the frequency decreases in ethanol containing 2% to 10% water while the ethanol flows through the measurement device. The measurements indicates that the higher water content is the more the frequency reduction is, though some deviation in the measurements is observed. This indicates that the frequency measurement of an unknown concentration of water in ethanol can be used to determine the water content in ethanol. The PVA coating is examined by microscopy and FTIR (Fourier transform infrared) spectroscopy.
References
[1]
Bruno, T.J.; Wolk, A.; Naydich, A. Analysis of fuel ethanol plant liquor with the composition explicit distillation curve method. Energy Fuels 2009, 23, 3277–3284.
Brown, R.J.C.; Keates, A.C.; Brown, A.S. Optimised determinations of water in ethanol by encoded photometric near-infrared spectroscopy: A special case of sequential standard addition calibration. Anal. Chim. Acta. 2011, 690, 47–52.
[4]
Dion, J.R.; Burns, D.H. Simultaneous determination of alcohol and carbohydrate content in commercial beverages by ultrasound frequency analysis. Talanta 2011, 86, 384–392.
[5]
Hoog-Antonyuk, N.A.; Olthuis, W.; Mayer, M.J.J.; Yntema, D.; Miedema, H.; van den Berg, A. On-line fingerprinting of fluids using coaxial stub resonator technology. Sens. Actuators B 2012, 163, 90–96.
[6]
Cao-Paz, A.M.; Rodriguez-Pardo, L.; Farina, J.; Marcos-Acevedo, J. Resolution in QCM sensors for the viscosity and density of liquids: Application to lead acid batterie. Sensors 2012, 12, 10604–10620.
[7]
Maeda, K.; Kim, B.C.; Kim, Y.H.; Fukui, K. Nucleation monitoring in cooling crystallization with a quartz crystal oscillator. Anal. Chim. Acta 2006, 558, 337–344.
[8]
Kim, B.C.; Kim, Y.H.; Fukui, K. Crystallization monitoring in supersaturated solution with a quartz crystal sensor. Anal. Chim. Acta 2003, 491, 71–80.
[9]
Joung, O.J.; Kim, Y.H.; Maeda, K.; Fukui, K. Measurement of hysteresis in crystallization with a quartz crystal sensor. Korean J. Chem. Eng. 2005, 22, 99–102.
[10]
Joung, O.J.; Kim, Y.H.; Fukui, K. Determination of metastable zone width in cooling crystallization with a quartz crystal sensor. Sens. Actuators B 2005, 105, 464–472.
[11]
Kim, B.C.; Kang, H.W.; Kim, Y.H. Crystal shape monitoring and supersaturation measurement in cooling crystallization with quartz crystal oscillator. Korean J. Chem. Eng. 2006, 23, 789–794.
[12]
Joung, O.J.; Kim, Y.H. Dew point measurement for organic vapor mixture using a quartz crystal sensor. Sens. Actuators B 2006, 113, 335–340.
[13]
Kim, Y.H. On-line measurement of monomer concentration in UV photopolymerization using a quartz crystal resonator. Korean J. Chem. Eng. 2011, 28, 1632–1635.
[14]
Kim, B.C.; Kim, Y.H. Monitoring photopolymerization of trimethylolpropane triacrylate using a quartz crystal resonator. J. Polym. Sci. A 2011, 49, 4578–4584.
[15]
Kim, B.C.; Maeda, K.; Kim, Y.H. Monitoring nonisothermal crystallization of thermoplastic polymers using a quartz crystal resonator. J. Appl. Polym. Sci. 2011, 120, 3370–3380.
[16]
Kim, Y.H. Measurement of thermal property of polystyrene using dual quartz crystal resonators. Korean J. Chem. Eng. 2011, 28, 1924–1926.
[17]
Kasai, N.; Sugimoto, I.; Nakamura, M.; Katoh, T. Odorant detection capability of QCR sensors coated with plasma deposited organic films. Biosens. Bioelectron. 1999, 14, 533–539.
[18]
Nakamura, K.; Nakamoto, T.; Moriizumi, T. Classification and evaluation of sensing films for QCM odor sensors by steady-state sensor response measurement. Sens. Actuators B 2000, 69, 295–301.
[19]
Sartore, L.; Barbaglio, M.; Penco, M.; Bergese, P.; Bontempi, E.; Colombi, P.; Depero, L.E. Polymer-coated quartz crystal microbalance chemical sensor for heavy cations in water. J. Nanosci. Nanotechnol. 2009, 9, 1164–1168.
[20]
Abbas, M.N.; Moustafa, G.A.; Mitrovics, J.; Gopel, W. Multicomponent gas analysis of a mixture of chloroform, octane and toluene using a piezoelectric quartz crystal sensor array. Anal. Chim. Acta 1999, 393, 67–76.
[21]
Kasai, N.; Sugimoto, I.; Nakamura, M. Discrimination of odorants of definite concentrations by using plasma-organic-film-coated QCR sensors. Sens. Actuators B 2000, 65, 114–119.
[22]
Wang, Y.; Ding, P.F.; Hu, R.F.; Zhang, J.M.; Ma, X.F.; Luo, Z.Y.; Li, G. A dibutyl phthalate sensor based on a nanofiber polyaniline coated quartz crystal monitor. Sensors 2013, 13, 3765–3775.
[23]
Liu, F.; Li, F.; Nordin, A.N.; Voiculescu, I. A novel cell-based hybrid acoustic wave biosensor with impedimetric sensing capabilities. Sensors 2013, 13, 3039–3055.
[24]
Yao, C.Y.; Qu, L.; Fu, W.L. Detection of fibrinogen and coagulation factor VIII in plasma by a quartz crystal microbalance biosensor. Sensors 2013, 13, 6946–6956.
[25]
Pejcic, B.; Barton, C.; Crooke, E.; Eadington, P.; Jee, E.; Ross, A. Hydrocarbon sensing. Part 1: Some important aspects about sensitivity of a polymer-coated quartz crystal microbalance in the aqueous phase. Sens. Actuators B 2009, 135, 436–443.
[26]
Pejcic, B.; Crooke, E.; Doherty, C.M.; Hill, A.J.; Myers, M.; Qi, X.; Ross, A. The impact of water and hydrocarbon concentration on the sensitivity of a polymer-based quartz crystal microbalance sensor for organic compounds. Anal. Chim. Acta 2011, 703, 70–79.
[27]
Pejcic, B.; Crooke, E.; Boyd, L.; Doherty, C.M.; Hill, A.J.; Myers, M.; White, C. Using plasticizers to control the hydrocarbon selectivity of a poly(methyl methacrylate)-coated quartz crystal microbalance sensor. Anal. Chem. 2012, 84, 8564–8570.
[28]
Buslov, D.K.; Sushko, N.I.; Tretinnikov, O.N. IR Investigation of hydrogen bonds in weakly hydrated films of poly(vinyl alcohol). Polym. Sci. A 2011, 53, 1121–1127.
