Determination of Acetaldehydes and Acrolein in the Gas Phase of Cigarette Smoke Using Cryothermal Gas Cromatography’

DETERMINATION OF ACETALDEHYDES AND ACROLEIN IN THE GAS PHASE OF CIGARETTE SMOKE USING CRYOTHERMAL GAS CROMATOGRAPHY’

By A. D. HORTON and M. R. GUERIN Analytical Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. 37830 Tobacco Science, 1974, 18-8, p. 19-22, ISSN.0082-4523.pdf

Acetaldehyde and acrolein in cigarette smoke have been de- faitt ;I ~I~IX’acroleiti clution peak. termined by gas chromatography of the gas phase which has Ott<, 01’ t ht, more successful methods ol’ cryotherm:tl been trapped at -75 ‘C on the head of the column in a cryo- 1t ’;tihItittp 1~~s developed by Laurette, L~erly and Young thermal gas chromatograph. A system which allows standard mix- tures to be sampled in the same manner as the cigarette has 1X I \\,ho t IX~IJK~ gas phaw in it copper “radiator” trap been developed. By use of this system, quantitative acetaldehyde intntersc~tl i tt liquid nitrogen. The trap wlrws~pumped at and acrolein values were assigned to a reference cigarette, which Iiquitl ttitt’o~i’tt temperature to r~~rnove noticot~detisible was used as a secondary standard. For twenty-five experimental cigarettes? the average acetatdehyde [:ontent ranged from 681 to g’;tst-‘. ;lttd thr contents \VPIY transferwd to the gas 1309,Lgiclg., and acrolein ranged from 59 to 139 Ug!cig.. with ~ht~ont;~tl)~t.~t~)ll,VIA ;L gas sampling valve, by heating an average coefficient of variation of 2.69, for acetaldehyde and 2.8% for acrotein. The Cl,,r, for acetnldehyde was 6.5% and for iht, 11’;11) it1 2111 oil bath. .Scrt;tldeh?dr and :tcrolein acrolein 6.9% \v(~w tlt~t~l~nritled on it 2%ft x ‘A-inch copper column ~);lc~l.?lYl\\.ilh lo’; L’(‘ONJ“ 51) HR 2805 on 80-to-100 mt’sh c b~~~ntosorb \V. =\ standard mixturr of :wet:llde- INTRODUCTION h>-tltl ;Ltl(l acroleitt xva: ti~a~)pd atld trattsfrrred in the (‘otttinuinjz studit~,~ of thtj ciliatoxicity oi the gas iamr rniittnt’r ;t.s the sample. z\ thermal cottdrtctivity I)h:lsr of cigarette smokr rcquitw the routine analysis dcic~tor was uwd for the analysis. of crrtain cotlstiturttts in sul~l~ot’t of the hiologic;ll T ht, tnrt hod developed at this laboratory differs rtwarch. The cili;ttoxicitv of ac~+aldc~h\-deand acrole- i ram ot h(~r c,r>wtherrnal methods, in that the gas phase in itt th(1 gas phase has been M-ell doc~umcntetl I 1.3). is trartst’errt4 ltuff bp puff from the smoking machine Numerous tcchttiquc,s for tl:t. :tnal~.sis of the a:ts to the g;t< cht.onlato~~.~tl,hic column, which h:w lx~~ l)haw for acrfaldeh~-de ;tttcl ;tcrol(titt havcb been relwrt- cooletl to 75°C. until the cirttrette h;ts been smoked csd. Philil)pc aud Ilobbs j 3) ;t1:11Jottcbs (4) dctcrmitted to the I)w>ct~ibed butt length. The column is then the 2,3-dit~itt~ol,hett~ih~(lt~~t~(~t~edrrivativc,s bag infrared tempt~rztturr Iwogrwmmed to elute the components. A attal~sis. ~Iorc t~rcrtttl>~. the maittstrwtn aas ph;wcs h;ls fl:~nrr ic;tliz;l?ioll drtectol. is uwd for this analysis. One been anal?-ztd tlirwt.1~ I,- gas chromat ogr;tphv on high of I hc> ;Lcl\.;ittt;txw oi” cr?othermal trapping of the ~:ts r~souftiort CO~UnlIlS th;tt srpat’;itt~ acetaldeh~tfe :tntI ph;tsr, directly ott the column is iIlus:tratrd by Rush- acroleitt ftwm most. itttcrfcrittg coti,~t.ituetits. Grab (5) ttcvk I !I i Hr showed striking differences in chromato- obtaittt4 exwllrttt se~~r;~1iott of the ~21s phase cons;ti- xr;tnt-: ot’ the pas phastb \vith and lvithout cryothcrmal tuent s, includitt~ ;tcetaldt~h~~de and ucrolein by use of f,l.;tj)ltitlg’. Hr did not itlrntif>- the contponrttts of his it glass capillar\- cwlumtt lCt0 nwters long coated ivith rhromat rolrr;~ms. UCOS~‘! LB 550. Xormatt, V/ cil 16) uwd ;I six port,, puff aver:tKin~ smoliittg tlt~~iw tlesi~ncd to gi1.e il APPARATUSAND REAGENTS crt~~s sect ional gas phase satnplt, of six ciaarrttes lighted in sequence. They dt~t~rminrd acetalttehvde, Thr ~:I,G (~hrom;ttc)~r;tph used f’ot, thi, s;tutly 1~~s a acrolrin and othrr compottc~trts in ;I few milliliters of Tracer. tnotit~l 150, cryothrrmal, dual column, dual the gas ph;tw on 2120.ft x 1H-in. ,stwinlrss steel column 1’11). mattufacturcd by Tracer, Inc., Austin, Texas. packed with 25’; U(‘ON”” 50 IIH 280X on 100 to 120 TM.0 1~ -inch 0.1). coppc‘l columns itt series were used mrsh (l.,l: E’iwbrick. for t ht* tlrtt~rmination of acctaldrh~de and acrolrin : a Cryot hermal t rappi ttg of t hl> ,zas phase of one or ::-ft t~lumn packed with 20f; Clarbowax” 200 on GO-to- mow cig-awttes is otttl 01’ thti ntow popular methods ot tl(h ntrsh Firebrick A4W folloued by a G-ft, column ptw~rntin~ degradation (agittp‘t of the sample. Irbh ltackcd \vith 20c;. /:i3,-os~di~tt’opiottitt~ilc on M-to-80 and Harlo\~ t’i~ traplwd thr ga; I)hasc in ;t IO\V tem- mrsh Firrl,t,ick AW. I,iquid nitroycn was the coolant petztttrrr still ;tntl tcm~tct~:ttrti~~~pt.oKrwmmed the still to for tht, cryothermal oven. transfer various !‘twtiotts to ’ htj gas chromatoaraph. Thtb -;mokittp machine was constructed at this labo- This method required the rt~mcn~al of CO, and H,O to r:ltc,t~J ;ind is illustrated in Figure 1. An electro- l)re\thttt over lo:tdinr the column. Krtrapping of ;I frac- mt~ch;tttit~;tl cam timer controls the operation of the tioti ctrtttaittin~ ;tc~rolt~in. nirth) I acetatr and isobutyr.- Shinttet, \.:tl\~ (puff duration) and of the G-port gas ;tldeh~de ;111d t.echt.ontatotrt,~tJ~h~ \~a:: requitw~ to ob- s;tmJlle I xI\Y~. both of which are solenoid operated. The paz x:tml)l~ loop has a volume of &-ml to insure that tto .s;tmplc is t>xh;tustc4 during the Z-second, 35-m] puff. ‘I’he (i-[wt’t gas sample valve is a product of Ovarian, ORNL-DwG 71-1s0593 PRDCEDURE C’i~/rrwtl~~ (‘otzrlitioni~r,u nnd Sclr~etion. All cigarettes SKINNER 3-WAY n’t’w contiitiotted for at least 48 hours in a room where SOLENOID VALVE the relati~t~ humidity is controlled to 60 t 2:; and the ttlmperature is controlled to ‘ici tz 2°F. Samples were / VARIABLE .wlrctrd from a batch of 100-200 cigarettes’ that were ( VOLUME free From obvious defects, e.g., pin holes, frayed wrap- pers and ,‘or loss of filler. Cigarettes were weight- selected hamdiscarding those differing by more than -C-20 mg from the average, and setting aside as samples, those \\ithin ? 20 mg of the average weight of the batch. Rc,sistance-to-draw (RTD) of the weight- selertrtl cigarettes was determined, and only those that matchcxtl within i ,5C; of the average RTD \vere used. Smil/ciii~/ ihfl Ci.qfrwttc rcr1tlA? ltrly.sisof 2 llCGus /‘I/trsc. Thtl helium flow was adjusted to 90 ml/min, i\lld thtx wlurnn \VHS cooled to -75°C. .4 standard Tobacco Science, 1974, 18-8, p. 19-22, ISSN.0082-4523.pdf I 6-PORT GAS cigarcxttca holder with a Cambridge filter and a dental DYNA-VAC SAMPLE VALVE d;tm “lip” ~‘as attached to the smoking machitte inlet, PUMP and the, puff volume was adjusted to 35 I’ 0.5 ml. The L-I l~uff tlurat iott was 2 1’ 0.1 seconds and thr puff interval Figure 1. Single port smoking machine ORNL-DWG-71-10593. JV:I?: 1 mirlutr. The cigarette was lighted on the 11uff. and smoked to a butt length of 23 mm for 85 mm o~r~w~ap for ORNL - DWG 73- 1892 ciparc%tcs. and to Ivithin 3 mm of the filter ci.wrettes. One clearing puff ~-as taken after the SMOKINGT%ACHINE AIR IN cinawtic \~as removed from the holder. The tcmprra- twe was programmed as shown in Figure 3. Attenua- tion \V;IS 2X x 10:’ at the beginning of the> chromato- gram. X ftrr isoprene was eluted, at trnuation was 32 s 10’:: :~f’tt~t. :tcrtaldehyde was elutcd, attenuation was 8 x 10’. and after acrolein was elated, attenuation was 32 x 10,~ until the chromatopram WX~ complete. Thr ovt’ll n-as cocbled to room tempcwture before the procetluw was repeated. At least four sample cigarettes and one reference cigarette mere smoked for each analysis. 1’r.cpro~c/if)t7 of rrud ,%I tuplir2g of Ac~tr~ldrI~~~df f~ttd Acrrbi~c Sfottrl~Ms. X &gallon carboy bins fitted with ;I two-hoits twbbcr stopprr. A glass tube ~~1s inserted in each holes. --\ Z-L Saran” bag MW attached to the ittttrr t*~ltl ot onr tube and a stopcock UX:: attached to thr t~stc~rttal end. The second tubt> \V;IJ btxttt at a right ;tnple ;u~tl ;I stc~pcock WXG attached to thr wternal end. COLLAPSED SARAN BAG (See Figure 2) The Sarann bag was evacuated and both stopcocks \I’C’W closed. Thr stopper WIS removed and enough acetaltlehyde or acrolein was added to the cat~boy to ptwluw approximately the amount of the ~ontpour~ti ~yuivalent to that in tht> refprettce ciga- t.ctte. Mhtw 10-35 ml puffs from thr carboy \vew tratts- frrrcd to the pas chromatograph. The carboy was Gtopp<~t~~l at~d tht, sample-air mixtuw IV:IS allowed to ecluilil)rate overnight. Ten, %-ml puffs mere trans- fr~rwd from the carboy VIA the smoking machine to tht yas ~hrnm;~tographic: column \vhieh had bc,en cc~c)ledto S%‘C. The procedure under the smokiny :md ;ttwlys..~ sect ion \~as wpeated uttt il the sample iv;ts eltt t etl. 5-gal CARBOY ‘I’hts C;.(‘. cotlnrctiott from the gas sample val!~ ~‘as ;tt tachrd to t \VO water-filled gas washing bottle*, with medium 1’rii r;. c~onnectedin series, and ten. %-ml puffs Figure 2. Apparatus for standardization of the acetoldehyde and acrollein procedure ORNL-DWG-73-1892. nwe takfbtr from the carboy. Acetaltlehydt> or acrolein iv;ts tl4c~tminrd in the ~vatcr ~olot.imi,tri~;tll~ ;ts the Walnut Creek, (‘alif. Z,l-dirtit t~o~~tt~tt~.lh~(lr~~~otte~lO~. Acetaldehyde Xl i- 5;; pure and Acrolein, 99 i ‘; pure The gas ~-ht~c~rn~~topla~)hicpeak atws wrt’e assumrd for preparation of standards was ol)t.ained from Aldrich to be equi\:alent tc, the quantitative calorimetric values: Chemical Company. Chicapo, Illinois. Saran” bags, obtaint~d for each component, as both samples wrre Z-litt>r capacity with ;I tube swled in thr writer of one taken from the same mixture. The data thus obtained rntl, xve1.eobtained from Xti~lwc’ (y~)nlp;ttry, Ann -4rbor, \V;U used t(l dtJtermitte acetaldehyd(a a11tl ;~~.roI~lit~itt a Michigan. iveIl chat.ac~tarized referrncr cigartat tc, and the rrfcbr- whtln the column is warmed. METHYL NITHITE 6 PROPICNALCEtiYCE+Z METhYL FURAN II METHANOL In agrt~t~mrnt with Laurene, et nl (8) a-e fi11d that ISOPRENE 7 E7HYL iOFMATE 12 ETHYL ACETATE thrJ stand;crt] must be introduced as nearly like the ACETALDEHYDE 8 METHYL ACETATE 13 ETHANOL ;;tniplt~ ;I:: possible. Introducing acetaldehgde and FURfiN 3 ACROLEIN 14 ACRYLONITRILE :w~olein into thr system at the position normally OUX- METHYL rORMATE IO ACETONE 15 ACETONITRILE plied [IV the tip-arrtte, before the Skinner valve, behind thr, Sk~nnt~r ~~~llve,and before and after the sampling v:ll\-~ ~~twduced evidence that losses occur in transit through tht~ lines. The greater the area exposed to the sample. tht greater the loss. Losses differed slightly, dvpentljJ,g upon whether pas phase was pwsent, or not --the loss being less, yener~ally, in the presence of the yas I)h:wr. LOSSof awolein was greater at each of the at)o\~t~ injection points than that of acetaldehyde. Aerolt~in i:: much more active chemically t,han acetal- d?hytltl, but much less volatile. Therefore, injection of staiidarxls 0I’ neat acrolein or acrolein solut,ions direct- I!, 011the I~,rIumn gave minimal losses and reproducible

flat a, but I~roduced consistently low results reflecting Tobacco Science, 1974, 18-8, p. 19-22, ISSN.0082-4523.pdf thr Iossw of xrolein in the sampling .system. Thtl prxctiw of defining the yuantltles of acetaldehyde at~tl xrolein relative to those delivered by a r~c~frrenv(~cigarette WRSadopted to insuw precise com- Iwxbi1il.v Irt+~vren standard and sample introduction. The twhrrique ill) illustrated in Fig. 3 and in Table 1 and descritwd in the methods section, was adopted to :tllow the :~trsolutc calibration of the chromatographic r’espo~w’. Thlx peak area s resulting from known quan- titirs 01’ ;twt;lldehyde and acrolt~in xvhjch reach the hcatl of thr column are used to convert the reference ci~;iix~tt,~ :II~w:: into absolute quantities. The refcwnce cigaixzt 1e is subwquent1y ustd ;M t hr standard. For (.ortx~l;il ion with other. data. e.g. biological, or flail c~c~ni~~~i~~isofiof two or more products, absolute

Table 1. Determination of acetaldehyde and acrolein in a monitor cigarette by comparison of data obtained by calorimetric and by gas chromatographic analysis G.C. Peak Area Reported Duplicate Equivalent F;,” b.v NO. Colori- to Puffs metric Colori- AWCI Average origdtna+or From Analysis, metric for Calculated Monitor S.fllple Corboy Vdlle Monitor k,g/cig. i’ q6yT. Acetdldehyde IO 11794190 19.71 lb.99 1017 Acrolein IO 129: 125 3.74 3.22 I09 III

Table 2. Precision of acetaldehyde and acrolein determination- average of 25 experimental cigarettes “V;;,.$;‘f. Avg. Rel Std Error % Avg. Cl,,-, Acetai- Acetal- Acetal- I qiciq de;y&de Acrolein2.8 dehyde1.5 Acrolein1.6 de;,;de Acrolein 6.9 ,19! puff 3.9 4.6 2.3 2.6 9.8 Il.4 , ,I, y,,.s I-_ 3; ,,I,‘r,,i,t ,//2. (II, lri~ilrs i’c iL!il = 1

Table 3. Acetaldehyde and acrolein deliveries of vxne experimental and some commercial cigarettes

Acetaldehyde Acrolein Cigarette nglci9 ~9lpuff /19/W i,s/cis />9/PUff 09/g” A Kentuckv Keferwre 1lRlI 981 88 1221 I28 I2 159 B C~mm~rcidl 85mm. Filtered 96 I440 102 IO 153 c c~mme~al a5mm.’ ‘.’ Non Filter?d IOI II65 III 12 I35 D Experimental, 85mm Charcoal Filtered 101 1302 b2 93 E Samr .,s “D”, Chdrcwl removed 121 I577 103 I2 155 F Commercial, 85mm Filtered Little Clqar. 104 1356 70 8 107 G Experimental, 85mm Marihuana I09 1531 145 14 199 I/i. i lit illi’ :,, I iibflil / ‘il, i?id

Table 4. Replicate determinations of acetaldehyde and acrolein in the gas phase of the Kentucky reference cigarette (1Rl) and in the monitor cigarette

Peak Areas Avg. ..-..r&n 1 RT.” -2 hva. -Jo Acetaldehyde-IRI 7071 7152 7403 7084 6;4 6Z9 7:1 7zq A;;:. i$i$ ;.“,” Acetaldehyde-Monitor 740 699 743 71 I 723 1017 2.7 Acrolein-IRI 638 bb5 546 585 bOD 624 663 b4b 621 6.6 Acrolein-Monitor 555 538 577 562 558 I1 3.1 Tobacco Science, 1974, 18-8, p. 19-22, ISSN.0082-4523.pdf