Characterization of CO 2 Laser Photoacoustic Spectrometer Intracavity Configuration and Its Application in Measuring Acetone Gas in Human Breath

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1 Proceedigs of the Pakista Academy of Scieces: A. Physical ad Computatioal Scieces 54 (3): (2017) Copyright Pakista Academy of Scieces ISSN: (prit), (olie) Pakista Academy of Scieces Research Article Characterizatio of CO 2 Laser Photoacoustic Spectrometer Itracavity Cofiguratio ad Its Applicatio i Measurig Acetoe Gas i Huma Breath Mitrayaa 1*, Nurul Muyasaroh 1, Mohammad Ali Joko Wasoo 1, ad Mohammad Robikhul Ikhsa 2 1 Physics Departmet, Faculty of Mathematics ad Natural Sciece, Uiversitas Gadjah Mada, Sekip Utara, Bulaksumur, Yogyakarta 55281, Idoesia 2 Iteral Medicie Ward, RSUP Dr. Sardjito, Faculty of Medicie, Uiversitas Gadjah Mada, Jala Kesehata, Kabupate Slema, Yogyakarta 55281, Idoesia Abstract: Photoacoustic spectrometer is a very effective istrumet for detectig low cocetratio gasses. I this research, a CO 2 laser photoacoustic spectrometer itracavity cofiguratio was characterized ad applied for measurig acetoe gas cocetratio i huma exhaled breath durig exercise o a treadmill. The characterizatio icluded laser power optimatio, scaig laser spectrum, makig resoat curve ad quality factor, measurig oise ad backgroud sigal, determiig lowest detectio ad liearity curve. Acetoe gas cocetratio was determied by aalyzig ormalized photoacoustic sigal usig multicompoet matrix. The optimum power was obtaied at 32.4 ± 0.5 W ad CO 2 laser spectrum cosisted of four lie groups. The highest laser absorptio lie of stadard acetoe gas was determied at 10P20. Quality factor was obtaied at 14.6 ± 0.6, oise at 1.7 ± 0.2 µv/hz 1/2, backgroud sigal at 10P to mv, lowest detectio limit of acetoe gas at 110 ± 14 ppbv, ad acetoe gas liearity gradiet o 10P20 was at kk 22 = ± Acetoe gas cocetratio i huma exhaled breath after exercisig o treadmill decreased from 43 % to 79 % tha before. Keywords: Acetoe gas cocetratio, exercise, itracavity cofiguratio CO 2 laser photoacoustic spectrometer, treadmill 1. INTRODUCTION Photoacoustic spectrometer (PAS) is a very effective istrumet for detectig trace gasses at low cocetratios. For the detectio of sample gas, PAS is based o eergy resoace betwee radiatio source ad excitatio eergy of gaseous molecule. Photoacoustic spectrometer had bee applied i all research fields [1 4]. Schramm et al. [1] succeeded i detectio of the NO 2, N 2 O, ad SO 2 gases from diesel machies exhaust by usig PAS. Schilt et al. [2] also used PAS to moitor the ammoia amout i the semicoductor idustrial area. Huber et al. [3] succeeded i developig the CO 2 -Sesor for Automotive Applicatios by followig the photoacoustic priciple. Popa ad Petrus [4] used CO 2 laser PAS to ivestigate the effect of heavy metals o plats by detectig the emitted ethylee ad ammoia gas. A sample is placed at photoacoustic cell, radiated by laser radiatio of which the itesity is modulated o photoacoustic cell resoace frequecy. The gaseous molecule absorbs laser radiatio eergy ad it is excited to a higher state. The excited state loses its eergy by collisios. The collisios betwee molecules cause the icreasig kietic eergy, ad the it causes the icrease i temperature. Ad the icrease i temperature causes the icrease i pressure. Because the itesity of laser radiatio is Received, April 2017; Accepted, September 2017 *Correspodig author: Mitrayaa; mitrayaa@ugm.ac.id

2 320 Mitrayaa et al modulated, the pressure fluctuates. The fluctuatio of pressure causes the acoustics which ca be detected usig microphoe [5]. I this research, a CO 2 laser photoacoustic spectrometer itracavity cofiguratio had bee characterized ad applied for measurig acetoe gas cocetratio of huma exhaled breath durig exercise o treadmill. CO 2 laser is radiatio source which radiates ifrared beam at the wavelegth area of 9.2 µm to 10.8 µm where there is more tha 250 molecular gasses of evirometal cocer with atmospheric, medical ad scietific spheres exhibitig strog absorptio bads [6]. Acetoe gas is a diabetes mellitus biomarker [7, 8]. Patiets pacreas with diabetes mellitus ca ot produce quite isuli to absorb glucose produced by food, whereas high blood glucose level causes the formatio of acetoe gas [9]. Diabetes mellitus ca be dimiished by exercises such as walkig o the treadmill [10]. 2. MATERIALS AND METHODS The photoacoustic spectrometer characterizatios iclude laser power optimatio, scaig laser spectrum, makig resoat curve ad quality factor, measurig oise ad backgroud sigal, determiig lowest detectio ad liearity curve (Fig. 1). Fig. 1. The CO 2 laser photoacoustic spektrometer itracavity cofiguratio scheme. Measurig of acetoe gas cocetratio of huma exhaled breath durig exercise o treadmill bega by takig the voluteer breath ad savig it i a sample bag through KOH ad CaCl 2 scrubber. A scrubber was used as the CO 2 ad H 2 O absorber. Voluteer breath was take five times, before exercise (decisio to- 1), after warmig up (decisio to- 2), after coditioig (decisio to- 3), after coolig dow (decisio to- 4) ad 5 mi after exercise (decisio to- 5) (see Fig. 8 ad Fig. 9). Warmig up: walkig o the treadmill 1.2 km h 1 for 5 mi. Coditioig: walkig o the treadmill 2.4 km h 1 for 20 mi. Coolig dow: walkig o the treadmill 1.2 km h 1 for 5 mi. Voluteer breath was flowed ito a photoacoustic spectrometer for detectig ad producig photoacoustic sigal. Sice the photoacoustic sigal is proportioal to laser power, it must be ormalized.

3 CO 2 Laser Photoacoustic Spectrometer Itracavity Cofiguratio ad Acetoe Gas Cocetratio 321 The ormalized photoacoustic sigal is a fluctuatig time fuctio eeded to choose the costat average regio. Acetoe gas cocetratio was determied by aalyzig ormalized photoacoustic sigal usig a multicompoet matrix as show i Equatio (1). 3 ( S ) = = k C,( i = 1,2,3) (1) i j 1 ij j where CC jj is gas cocetratio, (SS ) ii is ormalized photoacoustic sigal at highest absorbtio laser lie, kk iiii is a calibratio factor. Acetoe gas cocetratio after (CC ii ) ad before (CC oo ) exercisig o the treadmill was compared usig Equatio (2). C0 C C = i 100 % (2) C0 where CC is the acetoe gas cocetratio differece. The acetoe gas cocetratio of huma breath with ad without excercises o the treadmill was compared. 3. RESULTS AND DISCUSSION 3.1. The Characterizatio of CO 2 Laser Photoacoustic Spectrometer Itracavity Cofiguratio I this research, CO 2 laser was operated at 8.32 kv to 9.04 kv ad ma to ma, because at this voltage ad this curret, laser ca produce lasig easily. The optimum power was obtaied at (32.4 ± 0.5) W ad CO 2 laser spectrum cosisted of four lie groups, as show i Fig. 2. Fig. 2. CO 2 laser spectrum. The optimum power ca be obtaied by optics aligig. Gratig, laser tube, chopper, photoacoustic cell ad outcouplig mirror was aliged. He, N 2 ad CO 2 flow scale were arraged at 30, 70 ad 50. Optic compoet must be cleaed to obtai the optimum power because the dust o optic compoet surface ca iterfere laser propagatio. Photoacoustic cell was desiged as resoator to amplify the photoacoustic sigal. Resoace curve of acetoe gas is show i Fig. 3. The resoace frequecy was obtaied at f res = (1 650 ± 5) Hz ad the badwidth, at f res = (113 ± 5) Hz. Chopper was arraged at this frequecy, so that laser radiatio ca be

4 322 Mitrayaa et al resoated with the sample i photoacoustic cell. Quality factor (Q) ca be obtaied usig Equatio (3). Quality factor was obtaied at 14.6 ± 0.6. f res Q = (3) f where ff is resoace curve badwidth whe the sigal is the 1 2 x maximum sigal. Fig. 3. Resoace curve of acetoe gas. The highest laser absorptio lie of stadard acetoe gas, stadard ethylee gas, stadard ammoia gas were kow usig the absorptio spectrum of each gas. Every gas absorbs a laser lie or more ad resoats at a specific laser lie. Absorptio spectrum of acetoe gas is show i Fig. 4. The highest laser absorptio lie of the stadard acetoe gas was determied at 10P20. Sigals which iterferes photoacoustic sigal are oise ad backgroud sigals. The oise is caused by acoustical ad electrical vibratios. The oise was obtaied at 1.7 ± 0.2 µv/hz 1/2. It is used to determie the lowest detectio limit. The oise of photoacoustic spectrometer is show i Fig. 5. The backgroud sigal was measured before measurig the photoacoustic sigal. The example of the backgroud sigal measured at the laser lie 10P20 is show i Fig. 6. The backgroud sigal at 10P20 was mv to mv. System sesitiveess of photoacoustic spectroscopy is determied by the lowest detectio limit give by: C BDT = (4) ( S / N) where C is acetoe gas cocetratio,ss is ormalized photoacoustic sigal, ad N is oise.the lowest detectio limit of acetoe gas was 110 ± 14 ppbv.

5 CO 2 Laser Photoacoustic Spectrometer Itracavity Cofiguratio ad Acetoe Gas Cocetratio 323 Fig. 4. Absorptio spectrum of acetoe gas. Fig. 5. Noise of photoacoustic spectrometer. Time(s)

6 324 Mitrayaa et al Fig. 6. Backgroud sigal. Time(s) The correlatio betwee gas cocetratio ad photoacoustic sigal is determied by the calibratio factor usig multicompoet aalysis, a aalysis of sample that cosists of more tha oe gases. Gases used i this research are ethylee, acetoe ad ammoia. Aalysis was doe by measurig the photoacoustic sigal of each gas at each laser lie where the highest absorptio occurred. It is show i gas absorptio spectrum that the highest absorptio lie of acetoe gas was determied at 10P20, ethylee gas at 10P14, ad ammoia gas at 10R14. Every gas was broke up ito some cocetratios. The correlatio betwee the gas cocetratio ad the photoacoustic sigal was draw as a liearity curve. Liearity curve of acetoe gas at laser lie 10P20 is show i Fig. 7. The acetoe gas liearity gradiet was kk 22 = ± The correlatio factor of this liearity was RR 2 = Gradiet is a calibratio factor, the correlatio betwee gas cocetratio adphotoacoustic sigal. The gradiet of each liearity curve is used as a matrix compoet of the multicompoet aalysis as show i Equatio (5). ( S ( S ( S ) ) 2 = ) Gas cocetratio was determied by matrix iverse give by: C C C C ( S) 1 C = ( S ) 2 2 C ( S) 3 Hece, ethylee, acetoe ad ammoia gas cocetratio become: C = ( S ) ( S ) ( S ) C = ( S ) ( S ) ( S ) C = ( S ) ( S ) ( S ) (7) (5) (6)

7 CO 2 Laser Photoacoustic Spectrometer Itracavity Cofiguratio ad Acetoe Gas Cocetratio 325 where CC 1, CC 2 da CC 3 respectively are ethylee, acetoe ad ammoia gas cocetratios. (SS ) 1, (SS ) 2 ad (SS ) 3 respectively are ormalized photoacoustic sigals at laser lies 10P14, 10P20 ad 10R14. Fig. 7. Liearity curve of acetoe gas at laser lie 10P Measurig Acetoe Gas Cocetratio of Huma Breath Durig Exercise o a Treadmill A acetoe gas cocetratio graph of huma exhaled breath durig excercise o treadmill is show i Fig. 8. Fig. 8. Acetoe gas cocetratio graph of huma exhaled breath durig excercise o a treadmill. The acetoe gas cocetratio graph of huma exhaled breath durig exercise o treadmill is compared with the acetoe gas cocetratio graph of huma exhaled breath without ay activity as show i Fig. 9.

8 326 Mitrayaa et al Fig. 9. Acetoe gas cocetratio i exhaled breath of humas doig o activity. Acetoe gas cocetratio of huma exhaled breath durig exercise o treadmill is more fluctuative tha that without ay activity because the acetoe gas cocetratio is iterfered by the blood glucose level. The blood glucose level ca be iterfered by exercises. As show i Fig. 8, after warmig up, the acetoe gas cocetratio is higher tha before exercises. Warmig up was doe 5 mi, exercisig less tha 20 mi causes the liver to release the blood glucose that is saved as fuel. The icrease i the acetoe gas cocetratio is supposed to be caused by the blood glucose released, so it idicates a high sigal whe beig detected. After coditioig, the acetoe gas cocetratio drastically decreases, it is lower tha the cocetratio before exercises. Coditioig was doe for 20 mi, exercisig 20 mi, or if it is more tha 20 mi it may cause the muscles to take the blood glucose for fuel ad it decreases the blood glucose totality [5]. After coolig dow, the acetoe gas cocetratio icreases agai, causig the liver to release the blood glucose agai. Amout 5 mi after exercises, the acetoe gas cocetratio is lower tha that before exercises. The acetoe gas cocetratio of huma exhaled breath after exercisig o treadmill decreased at 43 % to 79 % tha before. It is i lie with with the hypothesis that acetoe gas cocetratio of huma exhaled breath after exercisig o treadmill decreases tha before because exercises ca reduce the blood glucose level. 4. CONCLUSIONS The lowest detectio limit for acetoe gas from the built photoacoustic spectrometer was 110 ± 14 ppbv. The system detected acetoe gas from the voluteer breath durig exercise o a treadmill usig laser CO 2 photoacoustic spectrometer. The acetoe gas cocetratio i huma exhaled breath after exercisig o a treadmill decreased from 43 % to 79 % compared with cocetratio i the prior to exercise breath. 5. REFERENCES 1. Schramm D.U., M.S. Sthel, M.G. Silva, L.O. Careiro, A.J.S.A. Juior & H.Vargas. Applicatio of laser photoacoustic spectroscopy for the aalysis of gas samples emitted by diesel egies. Ifrared Physics ad Techology 44: (2002). 2. Schilt, S., L. Théveaz, M. Niklés, L. Emmeegger & C. Hügli. Ammoia moitorig at trace level usig photoacoustic spectroscopy i idustrial ad evirometal applicatios. Spectrochimica Acta. Part A 60: (2003).

9 CO 2 Laser Photoacoustic Spectrometer Itracavity Cofiguratio ad Acetoe Gas Cocetratio Huber, J., C. Weber, A. Eberhardt & J. Wöllestei. Photoacoustic CO2-sesor for automotive applicatios. I: Proceedigs of the 30th Aiversary Eurosesors Coferece Eurosesors Bársoy, I., Z. Zsolt & B. Gábor (Ed.). Procedia Egieerig 168: 3 6 (2016). 4. Popa, C. & P. Mioara. Heavy metals impact at plats usig photoacoustic spectroscopy techology with tuable CO 2 laser i the quatificatio of gaseous molecules. Microchemical Joural 134: (2017). 5. Harre, F.J.M., G. Cotti, J. Oomes & S.L. Hekkert. Photoacoustic spectroscopy i trace gas moitorig. I: Ecyclopedia of Aalytical Chemistry. Meyer, R.A. (Ed.), Joh Wiley ad Sos, Chichester, p (2000). 6. Ivascu, I.R., C.E. Matei, M. Patachia, A.M. Bratu & D.C. Dumitras. CO 2 laser photoacoustic measuremets of ethaol absorptio coefficiets withi ifrared regio of μm. Spectrochimica Acta. Part A: Molecular ad Biomolecular Spectroscopy 163: (2016). 7. Wag, C. & P. Sahay. Breath aalysis usig laser spectroscopic techiques: Breath biomarkers, spectral figerprits, ad detectio limits. Sesors 9(10): (2009). 8. Miekisch, W. & J.K. Schubert. From highly sophisticated aalytical techiques to life-savig diagostics: Techical developmets i breath aalysis. Treds i Aalytical Chemistry 25(7): (2006). 9. Nayak, S. Ifluece of aerobic treadmill exercise o blood glucose homeostasis i oisuli depedet diabetes mellitus patiets. Idia Joural of Cliical Biochemistry 20(1): (2005). 10. Goldoi, M., M. Corradi, P. Mozzoi, G. Folesai, R. Aliovi, S. Pielli, et al. Cocetratio of exhaled breath codesate biomarkers after fractioated collectio based o exhaled CO 2 sigal. Joural of Breath Research 7(1): (2013).