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Sensors and Actuators B 188 (2013) 584– 589

Contents lists available at ScienceDirect

Sensors and Actuators B: Chemical

journa l h om epage: www.elsev ier .com/ locate /snb

uality assessment of automotive fuel and oil-improvingnvironmental sustainability

sman Latif a,b, Bita Najafia, Gerd Glanzniga, Franz L. Dickerta,∗

University of Vienna, Department of Analytical Chemistry, Waehringer Strasse 38, A-1090 Vienna, AustriaCOMSATS Institute of Information Technology, Department of Chemistry, Tobe Camp, University Road, 22060 Abbottabad, Pakistan

r t i c l e i n f o

rticle history:eceived 14 March 2013eceived in revised form 18 July 2013ccepted 19 July 2013vailable online 29 July 2013

edicated to Prof. Georg Winckler on theccasion of his 70th birthday.

a b s t r a c t

Ethanol as a radical scavenger being non-lead additive to fuel can act as quality improver as well as rangeextender, which abates the COx emission and helps to improve air quality. Its limited concentration inblended fuels is beneficial, whereas, higher percentage of ethanol damage automotive fuel lines. Thus,a sensor system has been designed for evaluating the quality of ethanol blended gasoline by utilizingmolecular imprinting technique in combination with transducers such as quartz crystal microbalances(QCMs). Moreover, a low cost miniaturized device based on interdigital transducers (IDTs) has also beendeveloped for characterizing ethanol/gasoline mixtures. Acrylic acid and sodium p-styrene sulfonatepolyelectrolytes as sensitive layers on IDT enable us to detect different percentages of polar ethanol in

eywords:thanol detectionolecular imprinted polymers (MIPs)

-octane/iso-octanehemical sensors

nterdigital transducers (IDTs)uartz crystal microbalances (QCMs)

non-polar gasoline hydrocarbons by resistive measurements. Another step in improving environmentalsituation is achieved by characterizing the lubricating oil to determine an optimal time of oil change.Mass-sensitive devices are also tuned by utilizing molecular imprinting approach to analyze the octanenumber of fuel by differentiating the isomers iso-octane and n-octane.

© 2013 Elsevier B.V. All rights reserved.

. Introduction

Oxygenates or oxygen-containing compounds such as alcohols,nd methyl ethers are commonly added to fuel as volume extend-rs and octane number improvers to produce lead free gasoliney introducing non-lead additives – quality improvers [1]. Ethanolas an advantage over methyl tertiary butyl ether (MTBE) as austainable fuel because it is produced from agriculture products.he use of bio-ethanol and bio-ethanol/gasoline blends in inter-al combustion engines has a long history as it has been used inermany and France since 1894 [2]. Moreover, in 1975 Brazil ini-

iated a crash program called as “Proalcool” to produce ethanollended fuels in response to 1973 OAPEC oil embargo and in 1980salf of the cars in Brazil was running on E95 (95% ethanol and% gasoline) [3]. The use of ethanol or ethanol/gasoline blend asuel is an alternative energy source not only to reduce CO, CO2,nd VOCs emission but also to overcome the dependence on fos-

il fuels [4,5]. These additives are added since oxygen present inhese quality improvers ensures the smooth burning of fuel [6].pproximately 65,000 million liters of ethanol were consumed all

∗ Corresponding author.E-mail address: Franz.Dickert@univie.ac.at (F.L. Dickert).

925-4005/$ – see front matter © 2013 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.snb.2013.07.065

over the world in 2010, mainly blend into E10 gasohol (a mixtureof 10% ethanol and 90% gasoline) [7]. In order to attain the ambi-ent air quality while reducing CO emission, the oxygenated fuelsrequire 2.7% oxygen by weight [8]. However, oxygenated fuels helpto abate the CO emission, whereas, other studies represents thatthese blended fuels may lead to other toxic and carcinogenic airpollutants like aldehydes and peroxyacetyl nitrates (PAN) [9–16].Thus, the use of higher ethanol content fuel will lead to increasethe level of toxins, carcinogens, mutagens, teratogens in the envi-ronment whereas small amount of ethanol in fuel is beneficial forsmooth performance of engine [17–20]. Different countries regu-late the amount of alcohol in fuel and states that the total alcoholcontents should not exceed more than 10% to the gasoline volumebecause problems may arise with fuel lines or connectors. Thus,there is dire need of a sensitive, robust, precise method for thecharacterization of ethanol/gasoline blends. A number of methodshave been reported for analyzing alcohol/gasoline mixtures whichare based on chromatography [21–23] or on spectroscopic tech-niques [24–29], mass spectrometry, and NMR [30–33]. Moreover,multidimensional chromatography is very sensitive and give bet-

ter resolution, whereas, difficulties arise in their operation and lackof on-the-spot analysis. The spectrometric techniques also requireextensive calibration to overcome the problem of signal overlap-ping.

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Further environmental improvement concerns the optimal timef oil change. If we replace the oil earlier then it will generate wasteaterial as well as becomes costly for consumer, whereas, delayingill deteriorate the engine. Moreover, the contamination of engine

il with unburned fuel diminishes its viscosity and on the long runhis effect is reversible due to evaporation but it is an importantause of the degradation of oil [34]. The fuel finds its way to therankcase from the cylinders and rings due to the internal leakagef the carburetor/injection. This contamination dilutes the oil andeduces its ability of lubrication and overall performance of engineil. The presence of fuel in engine oil also reduces the flash point ofutomotive oil which is one of the major causes of oil degradationnd releases different toxic and hazardous compounds in the envi-onment [35]. Thus, a mass-sensitive sensor system is fabricatedy following molecular imprinting approach for the analysis of oilontamination by unburned fuel to reduce intervals of oil change.

The quality of fuel can be assessed by its octane number. Theigher octane rating of fuel ensures its smooth burning in inter-al combustion engine or its tendency to resist self ignition. Lowctane number fuels leads to a problem called knocking due tore-ignition, which can cause severe damage to engine and otherssociated components. Octanes are the typical components ofasoline along with other hydrocarbons and iso-octane, a memberf octane family having octane number of 100, is taken as standardo ensure the quality of engine oil.

In this paper, we have designed sensor systems by combin-ng the sensitive layers with quartz crystal microbalance (QCM)36], and interdigital transducers (IDT) [37]. These miniaturizedevices help us to assess the quality of fuel by detecting not onlythanol content in blended fuels, contamination due to unburneduel, octane number of gasoline, but can also measure the isomericomponents i.e. n/iso-octane. Ethanol in gasoline not only enhancesctane number of fuel but also act as range extender. Moreover,ts limited level in fuel reduces the overall environmental pollu-ion in comparison to higher percentage of ethanol in fuel. Thus,wo sensor systems have been proposed based on mass-sensitivend interdigital transducers to evaluate the quality of fuel. Concen-ration dependent mass-sensitive ethanol responses are observedhile coatings with templated polyurethane as sensitive layers are

pplied. A low cost sensor device is fabricated by using acrylic acidnd sodium p-styrene sulfonate polyelectrolytes as sensitive mate-ials on IDT to detect the percentage of polar ethanol in non-polarasoline hydrocarbons. In the next strategy, mass-sensitive sensorevice is tuned to assess the quality of lubricating oil and fuel byemplating the sensitive material with iso-octane, which can mea-ure the oil contamination with unburned fuel, octane number ofasoline, and also differentiate between isomeric components i.e.,- and iso-octane.

. Experimental details

All chemicals are purchased from Fluka, Merck, and Sigma-ldrich in a highest available purity and used as received.

.1. Synthesis of coating materials

Polyurethane layer [38] is synthesized from 46.8 mg 2,2′-is(4-hydroxyphenyl)propane, 67.2 mg pholoroglucinol, which arehoroughly mixed and dissolved in 200 �L THF. Then 97.2 mg of,p′-diisocyanatodiphenylmethane is added followed by addition

f 10–15 �L pyridine to stimulate polymer formation. Then, ethanoln a percentage of 10% is added for imprinting, followed by heatingo 70 ◦C, after approximately 30 min the pre-polymer gets viscous.he templated material is spin coated on QCM after diluting with

ors B 188 (2013) 584– 589 585

THF and sensor becomes ready for measurement after completepolymerization which takes almost 24 h.

Acrylate [39] and styrene [40] polymers are prepared fromacrylic acid and sodium p-styrene sulfonate, respectively, whileusing sodium peroxodisulfate as radical initiator. Imprintedpolystyrene is synthesized from styrene as monomer, AIBN as rad-ical initiator. Sodium 4-vinylbenzenesulfonate (200 mg) and 50 mgof N,N′-hexamethylenebisacrylamide (HMBA) as cross-linker aredissolved in 0.9 mL of water as solvent and 10 mg sodium-peroxodisulfate as initiator while heating at 70 ◦C for 3 min. Theresulting pre-polymer is spin-coated on interdigital transducer(IDT) via “spin-off” process at 3000 rpm. To a mixture of acrylicacid/HMBA 80:20 (w/w)%, 5 fold volume of THF was added alongwith 2% AIBN as radical initiator. The pre-polymer is synthesizedfrom this solution by heating at 70 ◦C for 15 min followed by coat-ing the resulting pre-polymer to an IDT-structure. Afterwards, thesensitive coating is heated in oven for 2 h for complete polymeriza-tion.

Polystyrene is synthesized from styrene and divinylbenzene(DVB) to analyze the fuel contents in automotive oil. Both DVB andstyrene are supplied with polymerization inhibitor. DVB contains0.2% 4-tert-butyl catechol (TBC) as inhibitor which is removed byextraction with 2 M KOH, then washed twice with saturated NaClsolution. The styrene, however, contains only 0.005% of TBC andthis low concentration can also be removed by extraction. After-wards, azo-bis-isobutyronitrile (AIBN) as radical initiator is addedto mixture of styrene/DVB (40:60, V/V) and reaction is carried outat 60 ◦C for 15 min. The pre-polymer is templated with fuel (Iso-octane) followed by spin-coating on QCM and allowed to stand for24 h for complete polymerization.

Titania sol–gel layer is prepared by dissolving 67 �L of Ti(OBu)4in 400 �L iso-propanol and afterwards, 10 �L TiCl4 is added as aninitiator. The reaction mixture is heated at 60 ◦C for 1 h. After spincoating on gold electrode the titania layer is sintered at approxi-mately 400 ◦C to avoid any analyte incorporation.

2.2. Measurements

Mass-sensitive measurements are performed by dual electrodequartz crystal microbalance (QCM) by combining it with fre-quency counter (Agilent HP53131A) via home-made oscillatingcircuit and signals are displayed by using LabVIEW. The quartzcrystal microbalances of fundamental frequency of 10 MHz are pur-chased from “Quartz Technik (Plein, Germany)” having thickness of0.168 mm and 15.5 mm diameter, whereas, dual electrode structureis screen printed on blank QCMs with gold paste (GGP 2093126 W.C.Heraeus) and subsequently heating for 4 h at 400 ◦C. Afterwards,the polymer layers are spin coated on gold electrodes. One channelis covered with imprinted polymers, whereas, the other channel(non-imprinted or uncoated) serves as reference for differentialmeasurements. The stability of the cross-linked coatings was testedby comparing measurements in solvent and air. At first the sensorlayers were characterized according to the resonance frequency inair. Then they were stored for longer time in the respective sol-vent, followed by going back to measurements in air. Loss of sensormaterial in solution would result in an increase of frequency by1 Hz/ng. AFM measurements (Atomic-Force-Microscopy – VEECONanoscope IVa) yield a typical surface roughness of approximately3–5 nm. This can be optimized by varying spin-off speed and anappropriate viscosity of the pre-polymer. In this way the noise ofthe QCM sensors can be reduced. In the most cases, the imprinted

sensor coatings show a slightly higher roughness than those of thereference channel. The molecular cavities generated by templat-ing cannot be directly characterized according to shape and size byAFM since its tip exceeds in dimension the patterning of coatings.

586 U. Latif et al. / Sensors and Actuators B 188 (2013) 584– 589

Fig. 1. Interdigital transducer used for measuring the electrical properties of sensi-tT(

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Fig. 2. Mass sensitive frequency shifts are observed by ethanol imprinted

ive layer. The desired structure is fabricated on glass substrate via screen printing.hese transducers have 9 fingers on each electrode with equal gap and width300 �m × 300 �m), and the length of each finger is 7 mm.

Interdigital transducers are used for the measurement of resis-ances of sensitive layers by combining them with LCR meter (HP284A) and data was transferred to computer via GPIB interfacesing LabVIEW software. The desired structure of interdigital elec-rodes is fabricated on glass substrate via screen printing withommercial brilliant gold paste (GGP 2093126 W.C. Heraeus) andubsequently heating at 550 ◦C for 3 h. The developed interdigi-al transducer is shown in Fig. 1 having 9 fingers at one electrodef equal width and gap (300 �m × 300 �m), whereas, the lengthf fingers are 7 mm. The polymer layers are spin coated on inter-igital transducer, whereas, the resistances of sensitive layers areeasured at 20 Hz frequency and room temperature.

. Results and discussion

Oxygen containing compounds such as ethanol is commonlydded to fuel, due to its agriculture source, in order to increasehe octane number as well as range extender. Moreover, thisdditive leads to the smooth burning of fuel and behaves as qual-ty improver of lead-free gasoline. Its limited quantity reduceshe overall production of different pollutants. Thus, a sensor sys-em has been designed for the online measurement of ethanol inuel by following molecular imprinting approach in combinationith mass-sensitive transducers. The structural features of tar-

eted ethanol molecule are transferred to polyurethane materialia bulk imprinting method. The measurements show successfulmprinting effects which are attributed to molecular recognitionites available to uptake the analyte in shape-complementary cavi-ies. Dual-electrode quartz crystal microbalance with fundamentalrequency of 10 MHz is utilized for detecting ethanol percentagen gasoline as shown in Fig. 2. Ethanol-imprinted polyurethaneoated electrode serves for reversible inclusion of analyte, whereas,on-imprinted layer on second electrode is for differential mea-urements. The ethanol-blended fuels of different concentrations0%, 1%, and 2%) are exposed to sensor system and corresponding

requency shifts are observed. The figure depicts that an almosttable response (no frequency fluctuations) is achieved againstasoline with 0% of ethanol, whereas, with increasing concentrationf ethanol (1%) frequency decrease by about 125 Hz and a frequency

polyurethane layer coated on 10 MHz quartz crystal microbalance (QCM) whileexposing to the ethanol-blended fuels of different concentrations (0%, 1%, and 2%).

shift of 200 Hz is observed when the sensor device is exposed to2% ethanol blended gasoline. Negative frequency shifts observedwhile exposure to ethanol blended fuels is due to the incorpora-tion of templated analyte in selectively designed cavities. Otheringredients in gasoline such as carbonyls, acids, ketones, aldehydesterpenes etc. [41] show no interferences since the sensor device istuned for targeted analyte i.e. ethanol. Moreover, response timeof the sensor device is a few seconds. The sensor response is fullyreversible, since only non-covalent interactions are decisive for theinclusion of ethanol in the polyurethane. The high cross-linkingof the polymer guarantees its stability in solution. Thus, the sen-sor used was successfully tested for many weeks. These effectshighlight the advantages of molecular imprinting technique whichenables us to develop a tool for the detection of ethanol present inethanol/gasoline fuels.

Another strategy has been followed to detect the level of ethanolin gasoline by utilizing interdigital electrodes as transducer whichis covered by sensitive layers of polyelectrolytes, respectively. TheIDT is used to study the change in electrical properties of sensitivematerials while exposing to targeted analyte. In principle, alcoholhas an appreciably larger dielectric constant and solvating prop-erties than gasoline hydrocarbons. Thus, changes in resistancesof sensitive layers are analyzed by exposing to different percent-ages of ethanol in gasoline fuel. The sensor is operated in ac modewith an optimal frequency of 20 Hz by combining it with LCRmeter. The alternating current resistance of interdigital transduceris favorably measured at low frequencies to minimize capacitiveeffects. The change in conductance or resistance of modified elec-trodes in non-polar hydrocarbon fuels by addition of differentpercentages of polar ethanol is based on formation of mobile ions.Highly cross-linked acrylic acid and styrene (sodium p-styrenesulfonate) polymers are used as sensitive materials via polyelec-trolytes and exposed to the different concentrations of ethanolin blended fuels, as shown in Fig. 3. Concentration dependent(0–7% ethanol in gasoline) signals (resistances) of polyacrylic acidand sodium p-styrene sulfonate electrolytes are obtained. Poly-electrolytes are polymers consisting of monomers such as acrylicacid, or styrene sulfonate which carry ionizable groups [42]. Thesesubstances generate free ions in dependence on solvating powerand dielectric constant of solvents. In polar solvents, the ioniz-able groups of polyelectrolytes dissociate, leaving back charges onpolymeric chains which are called polyions (macro-ions), releasingsmall “counter-ions” in solution. Polyacrylic acid and polystyrenesulfonate form mobile cations while exposing to ethanol presentin gasoline [43,44] by ion solvation. This behavior of these poly-electrolytes is driven by donor–acceptor interactions with polarcomponent of blended automotive fuel. Sodium polystyrene sul-

fonate [45] is a strong polyelectrolyte, whereas, polyacrylic acid[46] is weak due to the presence of carboxylic group in their matrix.Thus, sodium p-styrene sulfonate polymer show minor resistances

U. Latif et al. / Sensors and Actuators B 188 (2013) 584– 589 587

Fig. 3. Resistance measurements of acrylic acid and sodium p-styrene sulfonatepolymers as function of different percentages of ethanol in fuel. The polymer layersarb

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sor system is not only able to detect the templated hydrocarbonsbut can also differentiate between n- and iso-octane components.A dual-electrode QCM sensor of fundamental frequency of 10 MHzhas been tuned for iso-octane by templating the polystyrene coated

re coated on interdigital transducer and the changes in resistance are observed atoom temperature and 20 Hz frequency. The repeatability of sensor design is showny measurements “o”.

han polyacrylic acid. Lowering of resistance is due to conver-ion of ion pairs M+X− or ionogens in mobile ions by solvationffects [47], whereas ion pairs or covalent compounds do not sig-ificantly contribute to conductance. The results in Fig. 3 showhat a more remarkable slope is observed for resistance changesf polyacrylic acid in comparison to sodium polystyrene sulfonaten parallel to ethanol addition. Sodium sulfonate consists of ionairs, mobile ions are generated by the interaction with ethanol,ince these free cations and anions are stabilized by ethanol. In thease of polyacrylic acid, however, two equilibriums are involvedue to ethanol solvation effects. Polyacrylic acid is no strong acid

n water and it will not dissociate in non-polar solvents. Thus,thanol will favor dissociation and the ions formed will only con-ribute to conductivity after their separation by solvation. In thisay, sodium sulfonate results show minor resistance and slope

han polyacrylic acid according to Fig. 3. The sensors are fullyeversible and stable, since electrostatic effects and protolytic reac-ion are fast. The rate determining step is primarily dependingn mixing the binary solution. In Fig. 3 the typical repeatabilityf a new sensor design is shown. The range of observed effectsan be varied by using different ionic networks, e.g. by alteringasicity of anions. Additional, cations with different ion diame-ers can be used to tune the desired effects. The generation of

obile cations by ethanol solvation is schematically shown inig. 4.

The unburned fuel can mix with the engine oil due to thenternal leakage through cylinder wall/piston into crankcase andhus, dilute the oil which in turn reduces its ability of lubrica-ion. The contamination of automotive oil with unburned fuel isn important cause of degradation of oil [48] and should be mon-tored by a sensor. Therefore, a sensitive layer is synthesized from

onomers such as styrene and divinylbenzene (DVB) [49] andemplated with fuel to detect its contamination in lubricating oil.

hese sensor materials exhibit hydrophobic interactions to hydro-arbons which results in reversible inclusion of analytes. The risend recovery times are in a suitable range for a sensor [49]. Theemplated polymer is coated on one channel of dual electrode QCM

Fig. 4. The illustration shows the solvation of polyelectrolytes in ethanol blendedfuels which describes the formation of mobile ions.

of fundamental frequency of 10 MHz, whereas, reference electrodewas optimized in respect to minimize any selective adsorptionto the gold electrode surface stemming from ingredients of oilor fuel. For this purpose bare gold electrode and titania coatedelectrode are compared. The steps in frequency shifts due to fueladdition are identical for 100 nm or 200 nm TiO2 coatings. Themeasurements (Fig. 5) are performed with the TiO2 coated (ref-erence electrode) electrode to avoid possible interactions withsulfur contaminants in the whole test solution. Titania coatingsfor reference electrode are synthesized by following a sol–gel pro-cess. Afterwards, the titania layer is sintered at approximately400 ◦C to avoid analyte incorporation. Positive frequency shiftsare observed while exposing to contaminated lubricants which isattributed to a decrease in viscosity by fuel addition. The cross-linked polystyrene, however, shows an incorporation of fuel. Thismass effect is opposite to the pure viscosity phenomenon. Thus, thechanges in frequency responses are smaller than those of the refer-ence channel. The differential signal allows detecting fuel contentsin oil.

Another strategy is followed to evaluate the automotive fuel onthe basis of their octane ratings which is an additional step aheadin parallel to analyze the ethanol contents in blended fuels. Thequality of automotive fuel directly relates to its octane numberor octane rating. The fuels with higher octane number withstandagainst compression and can be used in high performance engines,whereas, low octane rating leads to pre-ignition. Iso-octane has anoctane number of 100 and is used as a reference standard to checkthe quality of fuel or its resistance against self ignition. Thus, in thefollowing approach a sensor device has been designed to analyzefuel quality according to the level of iso-octane. The proposed sen-

Fig. 5. Sensor response of a polymer layer synthesized from styrene and DVB (40:60,V/V), templated with fuel (iso-octane) and exposed to lubricating oil possessingdifferent concentrations of fuel. The reference electrode is coated with titania layerfor compensating the physical effects and to avoid any interaction with test solution.

588 U. Latif et al. / Sensors and Actuat

Fig. 6. Sensor responses of iso-octane imprinted polystyrene against n-/iso-octane,wm

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hereas, blank electrode is used as reference in dual electrode quartz crystalicrobalance, rise and recovery times are shown in different abscissa scalings.

easuring electrode. The sensor system is exposed to its templatednalyte and resulting sensor responses are shown in Fig. 6.

The curve displays the mass sensitive responses of iso-octaneemplated polystyrene which shows a diminished frequency by60 Hz. A pronounced frequency shift is monitored on imprintedhannel, whereas, almost a minor non-selective effect is observedn the reference. Afterwards, the sensor system is exposed to-octane. The result depicts the higher sensor response in casef iso-octane in comparison to n-octane, showing the apprecia-le imprinting effects. Thus, selectivity of the sensitive materialn isomeric level is achieved. Therefore, differentiation of thesesomeric structures by QCM devices is of great interest whichs actually realized by the developed molecular imprinted sen-itive material. The rise time is within some minutes, whereashe recovery of the sensor is more sluggish, since the materialsed shows strong hydrophobic interactions. These results provehe availability of chemically and geometrically adapted cavitiesased on pre-formed non-covalent interactions during polymer-

zation.

. Conclusion

Ethanol is added to automotive fuels to ensure the smooth com-ustion of fuel in internal combustion engines and reduce theOx emission to atmosphere. Alcohols are most commonly useds additives as a sustainable fuel because of its agriculture sourcend to overcome the dependence on fossil fuels. Thus, sensitive,obust, and miniaturized online sensor systems were designedor monitoring the different concentrations of ethanol in ethanol-lended fuels. QCM sensors with imprinted polymers incorporatethanol from blended fuels. In the next strategy, we tuned a lowost sensor system by utilizing IDT as transducer to analyze theolar components (ethanol) in non-polar hydrocarbons. Polyacryliccid and sodium p-styrene sulfonate polymer served as sensitiveoatings. Solvation of these materials with ethanol leads to resis-ance changes by the formation of mobile ions. The effects observedan be tuned by varying the basicity of anions and ion diameters ofations.

Furthermore, imprinting allows the detection of fuel in lubri-ating oils by QCM sensors to optimize time of oil change. Even,ydrocarbons in fuel can be differentiated at isomeric level, as e.g.

so-octane and octane. Thus, an octane rating of automotive fuels

an be performed. It can be concluded that automotive oil and fuelan be monitored by chemical sensors to guarantee their appropri-te quality.

[

ors B 188 (2013) 584– 589

Acknowledgements

We would like to acknowledge Higher Education Commission(HEC) of Pakistan for providing funding for PhD of Usman Latif. Wethank Robert Bosch GmbH for partial support of the project.

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Biographies

Usman Latif worked in Department of Analytical Chemistry, University of Vienna,Austria and received his PhD in February 2011. Currently, he is working as AssistantProfessor in COMSATS Institute of Information Technology, Abbottabad, Pakistan.

Bita Najafi worked in Department of Analytical Chemistry, University of Vienna,Austria and received his PhD in December 2009.

Gerd Glanznig worked in Department of Analytical Chemistry, University of Vienna,Austria and received his PhD in May 2006.

Franz L. Dickert studied chemistry at University of Erlangen, Germany, and receivedhis PhD in 1970. He was appointed as professor of physical chemistry in 1980. In1994 he accepted a call to a chair of Analytical Chemistry at University of Vienna. Hismain interest is the development of chemical sensors, especially sensitive materials.