Comparative Chemistry of Cigarettes & Comparative Chemistry of Cigarettes & Smokeless TobaccoSmokeless Tobacco

Objectives of discussionObjectives of discussion

nn Overview of Chemistry Overview of Chemistry

nn Tobacco Tobacco –– Dark Tobacco chemical compositionDark Tobacco chemical composition

nn Smoked Tobacco Smoked Tobacco –– Cigarette smoke chemistryCigarette smoke chemistry

nn Routes of Exposure for smokeless compared to Routes of Exposure for smokeless compared to smoke tobaccosmoke tobacco

Dark Tobaccos: fire cured, air/sun Dark Tobaccos: fire cured, air/sun cured.cured.

nn Fire curesFire curesnn Hardwoods Hardwoods –– hickoryhickorynn Smoke curing adds flavors (Smoke curing adds flavors (phenolicsphenolics) ) nn Wood smoke condensate Wood smoke condensate nn Leaf undergoes chemical changesLeaf undergoes chemical changes

nn Air Cured Air Cured

Smokeless ProductsSmokeless Productsnn Manufacturing process*Manufacturing process*

nn Grinding followed by sievingGrinding followed by sievingnn High moisture > 50% High moisture > 50% -- oral and nasaloral and nasal

nn Snuff placed in mouth Snuff placed in mouth -- pinch or wrapped in porous pinch or wrapped in porous paper (Snus)paper (Snus)

nn Dry Dry --Sniffed into nasal cavitySniffed into nasal cavity

nn Grating and Cutting Grating and Cutting nn Moist Moist –– Oral or chewing tobaccoOral or chewing tobacco

nn Dry Dry –– chewing tobaccochewing tobacco

nn Stripping and ThreshingStripping and Threshingnn Plug Plug –– chewingchewing

nn Loose leaf Loose leaf -- chewingchewing

*Taken from *Taken from IngerInger WahlbergWahlberg and Tommy and Tommy RingbergerRingberger Chapter 14 :Tobacco Production, Chapter 14 :Tobacco Production, Chemistry and Technology Edited by D.L Davis and M.T, Nielsen, BChemistry and Technology Edited by D.L Davis and M.T, Nielsen, Blackwell Science LTD, 1999lackwell Science LTD, 1999

Smokeless Product CategoriesSmokeless Product Categoriesstfact_sheet_combined10stfact_sheet_combined10--2323--02.pdf02.pdf

nn Product CategoriesProduct Categoriesnn Chewing TobaccoChewing Tobacco--Twist, plug and scrapTwist, plug and scrap

nn Twist braided tobacco leavesTwist braided tobacco leavesnn Plug Plug –– pressed leaves in syruppressed leaves in syrupnn Scrap Scrap –– loose leaf loose leaf

nn Snuff finely ground tobaccoSnuff finely ground tobacconn SniffedSniffednn Dipping (placing between gum and cheek)Dipping (placing between gum and cheek)

nn Swedish Swedish SnusSnus (air cured)(air cured)nn Ground and sieved. Ground and sieved. nn Mixed with HMixed with H22O, O, NaClNaCl, Na, Na22COCO33 and flavorsand flavorsnn Heated with steam Heated with steam nn Can be refrigerated (prevents fermentation)Can be refrigerated (prevents fermentation)

n Nicotine Lozenge

Chemical Composition leafChemical Composition leaf

nn Over 3000 chemicals identified in leafOver 3000 chemicals identified in leafnn Nicotine 1 to 4% DMNicotine 1 to 4% DMnn Starches 29%Starches 29%nn Crude fiberCrude fibernn ProteinsProteinsnn Reducing sugarsReducing sugarsnn InorganicInorganic

nn Composition changes with curingComposition changes with curingnn Starches decrease to <6%Starches decrease to <6%nn Reducing sugars increase from 7 to 16%Reducing sugars increase from 7 to 16%nn Insoluble proteins decreaseInsoluble proteins decreasenn Soluble proteins increaseSoluble proteins increasenn Ammonia plus amide increasesAmmonia plus amide increasesnn Carotenoids decrease ( precursor to flavors )Carotenoids decrease ( precursor to flavors )

Chemical Composition leaf Chemical Composition leaf ContinuedContinued

nn Volatile componentsVolatile components

nn >150 (impart flavors) >150 (impart flavors) Routes of ExposureRoutes of Exposure

nn Fatty acid derived compoundsFatty acid derived compounds

nn TerpenoidsTerpenoids

nn Degraded Degraded carotenoidscarotenoids

nn Additional components if fire cured with hardwoods Additional components if fire cured with hardwoods >140 (Smoke condensates)>140 (Smoke condensates)

nn MaillardMaillard products products –– pyrrolespyrroles and furansand furans

nn NaphthalenesNaphthalenes and biphenyls and biphenyls

nn phenolicsphenolics

Components of interest in leaf for Components of interest in leaf for Smokeless and Smoke ProductsSmokeless and Smoke Products

nn Nicotine and pHNicotine and pHnn NitrateNitratenn TSNA (Tobacco specific nitrosamines)TSNA (Tobacco specific nitrosamines)nn Highly variable Highly variable –– ppm levels ppm levels ––decreased with decreased with

process changesprocess changesnn PAH’sPAH’s (polycyclic aromatic hydrocarbons)(polycyclic aromatic hydrocarbons)nn Heavy metalsHeavy metals ((210210Po, Po, CdCd, Se, Cr etc.), Se, Cr etc.)

Comparison of select Smokeless ProductsComparison of select Smokeless ProductsA McNeill, R A McNeill, R BediBedi, S Islam, M N , S Islam, M N AlkhatibAlkhatib and R West and R West TobTob. Control . Control 2006;15;642006;15;64--6767

Brand Moisture %w/w pHNicotine

mg/g

TSNA

ug/g

Benzpyrene ng/g

NDMA ng/g

Nitrite ug/g

Cr ug/g

Ni ug/g

Pb ug/g

As ug/g

Copenhagen (USA) 48 7.39 25.8 3.5 19.3 ND 6.7 1.69 2.64 0.45 0.23Snus (Sweden) 45.84 7.86 15.2 0.48 1.99 ND ND 1.54 2.59 0.5 0.3Baba 120 (chewing- India) 13.18 4.88 55 2.36 2.83 ND ND 2.08 2.94 1.56 0.4BABA Zarda (chewing - UK) 7.88 5.32 48.4 0.72 2.04 ND ND 2.34 5.88 1.18 0.24Ariva Lozenge 2.4 7.56 9.2 ND 0.4 ND ND 1.4 2.19 0.28 0.12

TSNA=NNN+NNK+NABND=nondetect

Smoked Tobacco ProductsSmoked Tobacco Products

nn CigarettesCigarettes

nn CigarsCigars

nn PipesPipes

Composition of Tobacco ColumnComposition of Tobacco Columnnn TobaccoTobacco

nn Tobacco ingredientsTobacco ingredientsnn FlavorsFlavors

nn HumectantsHumectants

nn PreservativesPreservatives

nn BindersBinders

nn FillersFillers

nn Chemical examples of Added ingredients Chemical examples of Added ingredients nn NaClNaCl and NHand NH33ClCl

nn Sweeteners Sweeteners –– sugars or saccharinsugars or saccharin

nn Glycerol and propylene glycolGlycerol and propylene glycol

nn Flavors Flavors –– menthol, licorice, menthol, licorice, isoamylisoamyl isovalerateisovalerate

Burning cigarette: Taken from Dr. Baker Burning cigarette: Taken from Dr. Baker presentation to LSRO presentation to LSRO June 8/9, 2004June 8/9, 2004

Chemistry of Burning Cigarette

nn Combustion ZoneCombustion Zonenn Complete oxidationComplete oxidation

nn Incomplete oxidationIncomplete oxidation

nn Distillation/Pyrolysis zoneDistillation/Pyrolysis zonenn PyrolysisPyrolysis

nn CombustionCombustion--sensitized pyrolysissensitized pyrolysis

nn Thermal decomposition Thermal decomposition -- pyrosyntheticpyrosynthetic reactions occurreactions occur

n Microexplosions

Combustion ProcessCombustion Process

n Complete - Oxidation of organic molecules to carbon, water and CO2

n CxHy + O2 -à X CO2 + Y H2On Requires sufficient heat and oxygen

n Incomplete n - Oxidation and reduction of organic

molecules to carbon, water, CO and oxides of organic molecules

Pyrolysis ZonePyrolysis Zone

n Thermal degradation of a chemical, usually to a smaller fragment:n C2H4 + Heat à CH4 (Methane) + C

n • Pyrosynthesis - Recombination of fragments resulting from incomplete combustion and pyrolysis to form new smoke components and reform components observed in tobacco leaf:n 3 C2H6 + Heat à C6H6 (Benzene)

Smoke FormationSmoke Formation

n Temperature decreases – Two phases formn Particulate phase – <0.1 to 1.0 µm-10% watern Vapor phase – gas phase

n Deposition and transfer ( Distillation )n Filtrationn Composition changes as the length decreases

Possible Pyrolysis productsPossible Pyrolysis productsgas phasegas phase

n Formaldehyden Proprionaldehyden COn Benzene

Possible Possible Pyrosynthesis productsproducts

n Benzenen Toluenen Benzaldehyden Phenoln Polycyclic Aromatic hydrocarbons

(PAH's)

Sidestream smoke: Taken from Dr. Baker Sidestream smoke: Taken from Dr. Baker presentation to LSRO presentation to LSRO June 8/9, 2004June 8/9, 2004

Mainstream Smoke and Sidestream Mainstream Smoke and Sidestream Smoke differencesSmoke differences

nn Natural convection drives the combustion and Natural convection drives the combustion and smoke formation processsmoke formation process

nn Burning zone temperature < 800 CBurning zone temperature < 800 C

nn The particles are formed above the burning zoneThe particles are formed above the burning zone

Smoke compositionSmoke composition

nn Vapor phaseVapor phase--8181--99% nitrogen, oxygen, carbon 99% nitrogen, oxygen, carbon dioxide, carbon monoxide, water and argon.dioxide, carbon monoxide, water and argon.nn >4000 other components identified.>4000 other components identified.

nn Tar Tar –– Total particulate weight collected on Total particulate weight collected on Cambridge filter minus the weight of alkaloids as Cambridge filter minus the weight of alkaloids as nicotine and water (FTC) nicotine and water (FTC) -- 7% nicotine, 10% water 7% nicotine, 10% water and 83% Tar.and 83% Tar.

Major compounds in the vapor phase of mainstream smoke of nonfilMajor compounds in the vapor phase of mainstream smoke of nonfilter cigarettester cigarettes

Compound Quantity/cigarette smokeda (% weight of mainstream smoke)

Nitrogen 280-320 mg (56 - 64%) Oxygen 50-70 mg (11-14%) Carbon Dioxide 45-65 mg (9-13%) Carbon Monoxide 14-23 mg (2.8 – 4.6%) Water 7-12 mg (1.4-2.4%) Argon 5 mg (1.0%) Hydrogen 0.5 – 1.0mg Ammonia 10-130 µg Nitrogen oxides (NOx) 100-600 µg Hydrogen cyanide 400-500 µg Hydrogen sulfide 20-90 µg Methane 1.0 –2.0 mg Other volatile alkanes (20)b 1.0-1.6 mgc Volatile alkenes (16) 0.4-0.5 mg Isoprene 0.2-0.4 mg Butadiene 25-40 µg Acetylene 20-35 µg Benzene 6-70 µg Toluene 5-90 µg Styrene 10 µg Other volatile aromatic hydrocarbons (29) 15 – 30 µg Formic acid 200-600 µg Acetic acid 300-1700 µg Propionic acid 100-300 µg Methyl formate 20-30 µg Other volatile acids (6) 5-10 µg d Formaldehyde 20-100 µg Acetaldehyde 400-1400 µg Acrolein 60-240 µg Other volatile ketones (3) 80-140 µg

Methanol 100-650 µg Other volatile ketones (3) 50-100 µg Methanol 80-180 µg Other volatile alcohols (7) 10-30 µg Acetonitrile 100-150 µg Other volatile nitriles (10) 50-80 µg d Furan 20-40 µg Other volatile furans (4) 45-125 µg d Pyridine 20-200 µg Picolines (3) 15-80 µg 3-vinylpyridine 7-30 µg Other volatile pyridines (25) 20-50 µg d Pyrrole 0.1-10 µg Pyrrolidine 10-18 µg N-methlypyrrolidine 2.0-3.0 µg

a Quantity that passes through a Cambridge glass fiber filter. b Parentheses show the number of individual compounds identified in a given group. c Estimate.

Tar Correlates withTar Correlates with

n Nicotinen Carbon monoxiden Ammonian Benzopyrene

Table 3-2. Numbers of substances in different chemical classes identified in Tobacco leaf and for cigarette smoke. (Phase one: the Feasibility of Testing ingredients added to cigarettes)

Chemical category

# in both leaf and smoke

Additional # in leaf

Additional # in smoke

Total # . detected

•Functional Groups

Carboxylic acids 140 450 69 659

Amino acids 16 95: 18 129 Lactones 39 129 135 303 Esters 314 529 456 1299 Amides and imides 32 205 227 464 Anhydrides 4 10 10 24 Aldehydes 48 111 106 265 Carbohydrates 12 138 30 174 Nitriles 4 4 101 109 Ketones 122 348 461 931 Alcohols 69 334 157 560 Phenols 40 58 188 286 Amines 37 65 150 252 N-nitrosamines1 19 23 18 60 Sulfur compounds 2 3 37 42 N-Heterocyclics

Pyridines 46 63 324 433

Pyrroles and indoles 3 9 88 100 Pyrazines 18 21 55 94 Non-aromatics 7 13 43 63 Polycyclic aromatics 0 1 36 37 Other heterocyclics 2 4 50 56 Ethers 15 53 88 156 Hydrocarbons Saturated aliphatics 44 58 113 215 Unsaturated aliphatics 10 38 178 226 Monocyclic aromatics 25 33 138 196 Polycyclicjmnatics 35 55 317 407 Pesticides 25 28 25 78 •Miscellaneous

19

112

110

241 •Inorganic and metallic

69

105

111

28

Routes of ExposureRoutes of Exposure

n Smoke chemistry drives the delivery of nicotine through inhalation. (Nicotine rapidly absorbed)n Along with other products

n Smokeless delivers nicotine through extraction and absorption at mucosal membranes of mouth and nose. (pH and free nicotine content important to delivery)

Routes of ExposureRoutes of Exposure

InhalationInhalation(MS, ETS) (MS, ETS)

Gastrointestinal Gastrointestinal

Nasal Nasal

RouteRoute

Primary RoutePrimary RouteAbsorption directly of vapor phase, Absorption directly of vapor phase,

evaporative gas from particle evaporative gas from particle deposition, diffusion from particle deposition, diffusion from particle

xxPrimary RoutePrimary RouteDigestion of Liquid extraction Digestion of Liquid extraction

of tobaccoof tobacco

xxA Primary RouteA Primary RouteSnuffSnuff

Liquid extraction of tobacco Liquid extraction of tobacco and volatiles and volatiles Chemical Chemical

Composition leaf Continued Composition leaf Continued

Smoke Smoke SmokelessSmokeless

ConclusionsConclusionsnn Smokeless TobaccoSmokeless Tobacco

nn Complex mixture and variable mixtureComplex mixture and variable mixturenn Data sparse compared to cigarettesData sparse compared to cigarettes

nn Cigarettes Cigarettes nn Highly studiedHighly studiednn Complex and variableComplex and variablenn Data mainly from Mechanical smoking machinesData mainly from Mechanical smoking machines

nn Mechanical smoking does not equal human Mechanical smoking does not equal human smokingsmoking

nn Aerosol composition very complex in smoke tobacco. Aerosol composition very complex in smoke tobacco. Route of exposure inhalation (delivered through lungs)Route of exposure inhalation (delivered through lungs)

nn Smokeless exposure is to extractable and volatile Smokeless exposure is to extractable and volatile components in mouth and gastrointestinalcomponents in mouth and gastrointestinal (nicotine (nicotine delivered orally)delivered orally)