Chemical composition analysis and its application in estimation of VOC emission rates from hydrocarbon solvent-based indoor materials

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Chemosphere, Vol.39, No. 14,pp. 2535-2547,1999 © 1999ElsevierScienceLtd.Allrightsreserved 0045-6535/99/$- seefrontmatter

Pergamon

PII: S0045-6535(99)00156-3

CHEMICAL COMPOSITION ANALYSIS AND ITS APPLICATION IN ESTIMATION OF VOC EMISSION RATES FROM HYDROCARBON SOLVENT-BASED INDOOR MATERIALS

Jiping Zhu*, Jianshun Zhang and Chia-Yu Shaw

Institute for Research in Construction, National Research Council Canada, Building M-24, Montreal Road Campus, Ottawa, Ontario, Canada K1A 0R6,

e-mail: [email protected]

(Receivedin USA 1February1999;accepted26 April1999)

ABSTRACT

A method for estimating VOC emission rates from hydrocarbon solvent-based indoor materials has been developed. The estimation is based on the assumption that the emission rate of individual VOCs is proportional to its molar fraction in the evaporative mixture at the time, its saturated pure vapor pressure and total remaining VOCs in the material. The paper demonstrates, through three hydrocarbon solvent-based polyurethane surface coating materials, a practical way to calculate these three parameters using chemical composition analysis results. The estimated total VOC emission rates were in good agreement with the results of weight loss experiments. © 1999ElsevierScienceLtd. All rightsreserved

INTRODUCTION

Emissions from hydrocarbon solvent-based indoor materials such as polyurethane and wood stains can be divided into at least two stages. In the first stage the emissions can be characterized in general as high but fast decaying, while in the second stage emissions are low and slowly decaying. Emissions during the first stage, especially in the initial several hours after application, are largely controlled by evaporation rates of the solvent [1,2]. Emissions can be described by both VB model [3] and VBX model [4]. Both models are based on mass transfer theory. VB model is used for describing total VOC (TVOC)

2535

2536 emissions only while the more advanced VBX model can be used for describing emissions of individual VOCs.

However, VBX model is very complex because it requires the knowledge on changes of molar fraction of each individual VOCs in a solvent mixture over evaporation time. For example, 120 differential equations are needed for a solvent containing 60 individual VOCs. In order for the model to be useful, the authors proposed using molecular weight of the most dominant component as the effective molecular weight of the VOC mixture to calculate the molar fractions [4]. Such approach does not recognize changes of effective molecular weight over evaporation time. In addition, both VB and VBX models do not consider the impact of non-evaporable components in the material on emission rates.

In this paper, we present a practical procedure based on principles of the VB and VBX models in estimating VOC emissions from hydrocarbon solvent-based indoor materials, using chemical composition analysis results.

EXPERIMENTAL

Testing Materials - Three polyurethane materials were purchased from local stores. The materials were analyzed within three months of purchasing. Description of the materials is summarized in Table 1. Chemical composition analysis - Perkin-Elmer glass tubes (5 mm i.d. by 89 mm long) were used to prepare samples. The tube was packed in the lab with 50 mg Carbopack B 60/80, 50 mg Carbopack C 60/80, and 25 mg Carbosieve SIII 60/80 separated by glass wool. The packed tube was cleaned and conditioned before sample loading. A sample of 10 to 20 mg of polyurethane liquid was added on to the glass wool at the Carbopack C end of the tube using a pasture pipette. The diameter of the pipette tip was narrowed to facilitate the process. The tube was then flashed with clean air for 5 minutes at a flow rate of 40 mL.min~ to disperse the liquid into the adsorbents. Both ends of the tube were then sealed with brass caps lined with Teflon ferrules until analysis.

Sorption tubes were desorbed on Perkin-Elmer ATD 400 thermal desorber under the following conditions: sample tube desorption at 300 °C at flow rate of 100 mL.min1 for 10 min; inner trap desorption at 300 °C at flow rate of 4 mL.min1 for 1.5 min. A high split ratio (10,000:1) during thermal desorption was used to avoid over-saturation of VOCs on GC column.

2537 Table 1: Product descriptions of testing materials with information from Material Safety Data Sheet (MSDS) that is related to VOC emissions. Material ID:

UR3

UR5

UR8

For wood floors, furniture, trim and doors.

On all interior wood surfaces including floors

78.7 mL.m"2 Over wood finishing/stains 24 hrs before normal use

12 - 14 mL-m-2 on bare wood, 3 to 4 coats recommended Dry to touch: 1 hr 18 hrs before use

Petroleum Distillates (55-65%)

Mineral Spirits (<70.0% by Weight) Xylene (<2.0% by Weight)

NA

860 - 870 g-L-~

NA

520 g.L"1

485.4 - 553. 9 g.L-1

<70% (v/v)

NA

37.96 - 44.34

NA

Product description: Material Uses:

For interior wood surfaces such as wood floors, table tops, cabinets, furniture and doors. Application: 78.8 m L . m "2 Over bare wood or oil wood stains Drying Speed: Dry to touch: 2 hrs Fully cured: 72 hrs Composition and Information on Ingredients: Aliphatic hydrocarbon solvent (50% by Weight) Mixed xylene (2%) Isopropyl benzene (1.08%) Trimethylbenzene, mixed isomers (1.06%) Physical and Chemical Properties: Bulk Density: V.O.C.: % non-Volatile:

Analysis of thermal resorption effluent was carried out on a HP GC/MS (model 5890 GC and 5989 MS) which was connected to the ATD 400. A 60-meter long DB-5 capillary column (0.32 mm ID, 0.25 p,m film thickness) was used to separate VOC components in the sample. Initial GC oven temperature was maintained at 10 °C using liquid CO2 during resorption. The temperature was then increased to 240 °C at a rate of 10 °C/min, and held for 2 rain. GC peaks were identified by comparing their mass spectrum with that in a standard MS library (NBS75K). Percentage weight of each compound was calculated based on peak areas assuming all compounds have equal response to the detector.

Weight loss measurement - 0.5 g (accurately weighed to 0.001 g) of test sample was added to a pre-weighed aluminum weighing-pan. The pan was then placed in a fume hood for the experiment. The fume hood was operated with low ventilation rate to mimic the indoor air movement. Air velocity over the specimen surface was determined by using hot wire technique. The weight of the pan was measured at pre-determined time intervals until itbecame constant.

2538 RESULTS AND DISCUSSION Theoretical Emission factor (EF) in VBX model can be summarized by equation 1:

EFi.(t) = k~ (Pvi x xi.(t) -

(I)

Ci)

Where, kr,i (m'h-1) is the mass transfer coefficient of compound i, Pvi (mg'm3) is the vapor pressure for pure compound i expressed as concentration in volume, xi.(t)is the molar fraction of compound i in solvent mixture at time t, and Ci (mg.m-3) is the concentration of compound i in air [4].

k~ is a function of diffusivity of the compound i in air under a given environment. Since diffusivity values among common indoor pollutants are quite similar at the range between 0.02 to 0.03 m2.hl , except for formaldehyde that is 0.06 m2.h-~ [5], a single mass transfer coefficient has been suggested to represent all VOCs in hydrocarbon solvent-based indoor materials [4]. In this study, a single mass transfer coefficient has been used for the reasons discussed above.

For convenience, we use the term emission rate (ER) throughout this paper. By definition, Emission rate (mg.h1) is emission factor multiplied by surface exposure area A (m2), on which indoor material is applied. Solvent-based indoor materials such as polyurethane contain non-evaporable components like polymer resins and pigments. The impact of non-evaporable components on the evaporation rate has to be taken into consideration when estimating emission rate. One of such impact is that non-evaporable components will compete with the evaporable component for occupying the exposure surface, whereby reducing the effective exposure surface for VOCs. Assuming the VOCs and nonevaporable components are homogeneously mixed and the size of a compound is proportional to its molecular weight, the effective exposure surface for VOCs at time t (t) can be described in equation 2.

(t) = A × [VOCWT(t) / (VOCWT(t) + Non-Evap.WT)]

(2)

Where, A (m2) is the area on which the indoor material is applied, VOCWT(t) is the total VOC amount at time t and Non-Evap.WT is the total non-evaporable amount in the applied material. While the amount of VOCs in the material is changing over time, the non-evaporable amount in the material remains the same. This results in the change of the ratio between VOC amount and non-evaporable components. Equation 2 can be applied to hydrocarbon solvent-based indoor materials that do not contain noticeable amount of water.

2539 Because of the large airflow exhausted by the fume hood in this study (see weight loss measurement experiment), VOC concentrations in the air is considered to be negligible compared to that at the surface interface. Therefore, the concentration Ci in equation 1 is considered to be zero in this paper.

Summarizing the above discussion, equation 1 can be re-written into equation 3:

(3)

ERi,(t) = (t) × km × Pvi × Xi,(t)

Chemical composition analysis Emission rates usually are measured in dynamic chambers under defined test conditions [6]. The initial VOC concentrations in the materials are often determined independently to help the estimation of percentage VOC amount being emitted over time [7]. VOC content is normally analyzed based on EPA Method 311 in which the indoor material is extracted with a solvent followed by injection of small quantity of the supernatant into GC/MS for analysis [8].

........

ii!iiil

. . . . . Decane Undecane

~ o o o o = ~ o o o o

~ o o o o o ~

o

o

o

o

oc

e

Figure h GC/MS chromatogram of UR8. The material was deposited on a thermal desorption tube and thermally desorbed into GC/MS instrument for analysis, see Appendix for the list of VOCs identified. In this study we have used thermal desorption method to introduce samples into GC/MS for analysis. Thermal desorption method eliminates the needs for solvent extraction, thereby avoiding potential interference of the solvent with early eluting components of the material on GC chromatogram. Three materials, coded as UR3, UR5 and UR8, have been investigated in this study (Table 1). Information provided by the manufacturers in their Material Safety Data Sheet (MSDS) indicated that the main volatile component is aliphatic hydrocarbons (50%, 55 - 65% and <70% for UR3, UR5 and UR8 respectively). In addition, UR3 contained small quantity of xylene (<2%), and UR8 contained xylene

2540 (2%) and C3- benzene (2%). UR5 did not have any aromatic hydrocarbons. Chemical composition analysis results have confirmed these MSDS data: VOCs in all three materials were mainly the aliphatic hydrocarbons ranged from C8 to C 12, and C2- to C5 cyclohexane derivatives (Figure 1).

Identification of GC/MS peaks was done by comparing the MS spectrum of the peak with that in the standard MS library. In some cases, where the full identification was not concluded, partial structure such as chemical class or molecular weight or both was identified. For example, If the MS spectrum indicates that the peak is a C10 hydrocarbon but fails to identify which of the C10 hydrocarbon isomer it is, the peak is then identified as C10 hydrocarbon only. Peak identification and the amount of each peak of all three materials are listed in the Appendix. The amount of each VOC in the material listed in the Appendix was based on the amount applied to the weighing-pens in weight loss experiment (see experimental). About 60 peaks were identified or partially identified for each material. The sum of these peak areas represents over 95% of the total area on the chromatograms. In other words, only less than 5% of VOC amount were not accounted for in the chemical composition analysis.

50

/ m 3) = 2 5 1 2 . 3

x exp(-0.23716

x RT(min)'

2

1;

1~

' 1;

" ~'1

'

~'3

25

'~'7'

' '2'9'

GO Retention Time (rain) Figure 2: Relationship between vapor pressure (v.p.) of a compound and its retention time (RT, in rain) on gas chromatogram under the analysis condition, see experimental for GC condition. Calculation of saturated vapor pressure For the majority of these 60 compounds, saturated vapor pressure values are not available in the literature. The values however can be calculated from GC retention times of peaks in chemical composition analysis. For example, under the experiment conditions of this study, a relationship was found between GC retention time and vapor pressure (Figure 2). Published data of octane, nonane, decane, undecane and dodecane by Gut et al. [4] were used as reference compounds in establishing the

2541 relationship. The correlation coefficient (r) of all five compounds was 0.99995. Equation in Figure 2 was used in this study to calculate saturated vapor pressure values of all peaks listed in the Appendix.

Calculation of molarfractions The other key parameter used for estimating emission rate in equation 3 is the molar fraction (xi) of each individual VOCs in the evaporable mixture at any given time t. In chemical composition analysis molar fractions are calculated from the weight (Wi) of a VOC and its molecular weight (MWi) (equation 4).

(4)

Xi ----(W i ] MWi) / ~~(W i ] MWi)

Ideally, each peak should be quantified against the standard of that compound. However, in reality, it is impractical to have standards of all compounds, especially if a peak is not fully identified. For hydrocarbon solvent-based indoor materials, however, relative response factors (RRFs) of total ion current in GC/MS were found similar among the VOC components. Table 2 shows the RRFs of aliphatic hydrocarbons (HC) (from C6 to C14) and cyclohexane (CHX) derivatives (C2- and C3-). The data were collected from calibration standards in our routine thermal desorption GC/MS analysis on VOC emissions from indoor materials. The RRFs to nonane were from 0.99 to 1.02 among the aliphatic hydrocarbon compounds, with exceptions of hexane (0.96)and C2-cyclohexane (0.92). It is therefore reasonable to assume that VOCs from hydrocarbon solvent-based indoor materials have equal response factors to GC/MS detector. In other words, weight percentage of each compound in the evaporable mixture is equal to the percentage of the peak area on the GC/MS chromatogram. The weight of each individual VOC was then calculated by multiply the percentage of peak area with total VOCs applied (Appendix).

Table 2: Relative response factors of aliphatic hydrocarbons (nonene = 1) (RRF = relative response factor, RSD = relative standard deviation, HC = hydrocarbon, CHX = cyclohexane, n = number of analysis). C6

C7

C8

C9

C10

Cll

C12

C13

C14

C2-

C3-

HC

HC

HC

HC

HC

HC

HC

HC

HC

CHX

CHX

RRF

0.96

0.99

0.99

1

1.01

1.01

1.01

1.01

1.02

0.92

0.99

RSD

12.5

8.9

4.7

0

4.5

8.4

12.0

13.8

15.7

4.4

6.7

N

30

30

30

30

30

30

30

30

30

20

20

Molecular weight (MWi) of each peak in Appendix was based on identification of the peak. If the molecular weight could not be determined due to lack of appearance of molecular ion in the spectrum or

2542 structure information, it was estimated using the average molecular weight of two peaks eluting before and after the compound.

Calculation of Emission Rate The calculation of emission rate was done using a spreadsheet on a personal computer based on equation 3. Time increment of 0. lh was used in the calculation. The amount and the molecular weight of each compound in the material provided by the chemical composition analysis results were used to calculate molar fractions of the VOCs (equation 4). Initial emission rate (ER(t_-o))of individual VOCs and initial ratio of VOC and non-evaporable components were calculated according to equations 2 and 3. These two initial values were then used to calculate the amount of VOCs emitted (AW) during the first time step (0 to 0.1 h) (equation 5). At time t = 0.1h, the remaining VOC amounts were calculated by taking away emitted VOC amounts from initial ones. ER at t = 0.1h was calculated based on the remaining VOC amount at t = 0.1h. The

ER(t_--O.lh)value was then used to calculate the amount emitted

during the next time step from 0.1h to 0.2h, and so on. It will be more accurate using the average ER and average weight ratio at beginning and end of the time step. However, since the ER and weight ratio at the end of the time step have to be calculated based on the remaining weight of each VOCs, they can not be calculated from the same time step. Therefore, ER and weight ratio at the beginning of the time step are used instead.

W(t+l) = W(t) - (ER(t) × At)

(5)

Emission Rate from Weight Loss Measurements In the weight loss measurement, the weight of a material was measured over time until the weight became constant. Weight loss measurements were conducted on all three polyurethane materials (UR3, UR5 and UR8). Weight loss experiment also provides data on total amount of non-evaporable component to be used in equation 2.

In order to compare the weight loss data with the estimation of emissions based on results of chemical composition analysis, the material was placed in an aluminum weighing-pan to avoid substrate effect. Further, the weighing-pan was placed in a fume hood with ventilation to achieve near zero concentration in the gas phase during evaporation (no back pressure).

The air velocity over the specimen surface under the experimental condition was independently measured to be about 0.04 - 0.05 m-s -1. Using graphic examples provided by Sparks et al. [5], the value of

2543 mass transfer coefficient was estimated to be around 10 m.h1, with a diffusivity of 0.02 mZ.h1 and a sample exposure area of 0.002 m 2.

Table 3 summarizes the model parameters calculated from total weight and total emitted VOCs of the three materials. The initial emission rate of TVOC, ER0,rvoc, in the table was the sum of individual E TM ~,i at time = zero (equation 3), based on chemical composition analysis.

Table 3: Weight loss experiment parameters and results of three polyurethane materials. Sample

UR3

UR5

UR8

Total Wt (mg)

492

503

579

Emitted Wt (mg)

280

270

326

% Evaporated

57

54

56

ER0,awoc (rag-h-I)

201.2

186.9

187.3

Exposure Area (m2)

0.002

0.002

0.002

Coefficient km (m'hl )

10

10

10

100

UR5 UR3

10

8

0.1 0

1

2

3

4

5

6

7

Evaporation Time (hour) Figure 3: Predicted TVOC emission rates from three polyurethane materials under the evaporation condition of mass transfer coefficient of 10 m-h-~ and exposure surface area of 0.002 m 2. The predicted total VOC emission rates from three polyurethane materials are illustrated in Figure 3 based on chemical composition of the material under the conditions of weight loss experiment (Table 3). Neither of three emission rate decay curve follows the first order exponential decay. Only in the first

2544 two hours were the curves close to first order decay [2]. The curves are in fact quite difficult to describe using any single mathematical equations.

Figure 4 shows good agreement between experimental data of total weight remained in the weighing pan and the predictions based on chemical composition analysis results for all three testing materials (equation 5). This indicates that adequate predictions on VOC emission rates from hydrocarbon solvent-based indoor materials can be made using results of chemical composition analysis and total amount of non-evaporable components in the material.

The agreement between predictions based on chemical composition analysis and experimental data of weight loss experiment can also be analyzed quantitatively [9]. When predicted values were plotted (Y-axis) against the remaining weight in aluminum weighing pan of the weight loss experiment (X-axis), best-fit linear regression produced slopes that were close to the idea match of 1.0 in all three cases (Table 4). The correlation coefficients of the least square regression between the prediction and the experimental data were all greater than 0.998 in all three cases, reflecting strong correlation between the two data sets. The intercept should be zero should the two data sets matched ideally. A small positive intercept value (Table 4) indicates that the predicted value of remaining weight is slightly higher than the actual experimental data. However, the value is well below the criterion (25 % of the average values) for intercept specified in ASTM Guide [9]. 600"'.

.

.

.

.

.

.

.

.

.

.

\ m 500 ~ ~

.

.

.

.

.

.

.

.

.

.

.

~

-- UR3: Prediction UR5: Prediction - - - - - UR8: Prediction ~ UR3, Experiment [] UR5, Experiment o UR8, Experimen...~t

\ ~ \

,,',, %

200

0

1

2

3

4

5

6

7

Elapsed Time (hour) Figure 4: Total weight remained in the aluminum weighing-pan over evaporation time. The prediction lines were based on results of chemical composition analysis.

2545 In conclusion, the method developed in this study provides an alternative to dynamic chamber tests for the estimation of evaporation-controlled VOC emissions from hydrocarbon solvent-based indoor materials. VOC emissions from various indoor materials can be compared based on their chemical composition using this method, which is much simpler than the dynamic chamber test. The prediction on VOC emissions from an indoor material can also be made when the evaporation conditions such as exposure area, amount of materials applied, surface air velocity over the exposure surface are defined.

Table 4: Quantitative comparison of predictions and experimental data for three polyurethane indoor materials.

Line of regression, slope Line of regression, intercept Correlation coefficient

UR3

UR5

UR8

0.996

1.025

1.008

1.0

12.5

11.5

0.9989

0.9983

0.9990

ACKNOWLEDGEMENTS

The authors would like to thank Ms. Ewa Lusztyk (Institute for Research in Construction, National Research council Canada) for technical assistance.

REFERENCES

[1] Chang, J. C. S. and Guo, Z. (1992) Characterization of Organic Emissions from a Wood Finishing Product - Wood Stain. lndoorAir, 2, 146 - 153. [2] Zhang, J.S., Nong, G.I Shaw, C.Y. and Wang, J.M. (1999) Measurements of Volatile Organic Compound (VOC) Emissions from Wood Stains by Using an Electronic Balance. ASHRAE Journal, in press. [3] Tichenor, B.A., Guo, Z. and Sparks, L.E. (1993) "Fundamental Mass Transfer Model for Indoor Air Emissions from Surface Coatings", Indoor Air, 3, 263 - 268. [4] Guo, Z., Sparks, L.E., Tichenor, B.A. and Chang, J.C.S. (1998) Predicting the emissions of Individual VOCs from Petroleum-Based Indoor Coatings. Atmos. Env., 32 (2), 231 - 237. [5] ASTM Committee D-22 (1998) Standard guide for small-scale environmental chamber determinations of organic emissions from indoor materials/products, ASTM D5116 - 9 8 (revised), American Society for Testing and Materials. [6] Fortmann, R., Roache, N., Guo, A. and Chang, J.C.S. (1997) Characterization of VOC Emissions from an Alkyd Paint. Proceedings of 1997 Engineering Solutions to Indoor Air Quality Problems

2546 Symposium, Air & Waste Management Association and U.S. EPA's National Risk Management Research Laboratory. July 21-23, 1997, Research Triangle Park, NC, USA. [7] EPA Method 311 (1995): Analysis of Hazardous Air Pollutant Compounds in Paints and Coatings by Direct Injection into a Gas Chromatograph. 40 CFR Part 63, Appendix 486. [8] Sparks, L.E., Tichenor, B.A., Chang, J. and Guo, Z. (1996) Gas-Phase Mass transfer Model for Predicting Volatile Organic Compound (VOC) Emission Rates from Indoor Pollutant Sources. Indoor

Air, 6,31-40. [9] ASTM Committee D-22 (1997) Standard Guide for Statistical Evaluation of Indoor Air Quality Models, ASTM D5157 - 97, American Society for Testing and Materials.

Appendix: Identification of VOCs their quantity in three materials (GC RT = retention time on gas chromatogram, P = saturated vapor pressure) GC RT (min) 13.70 14.50 14.75 14.83 15.80 15.94 16.01 16.16 16.77 16.96 17.17 17.49 17.69 17.78 17.90 18.01 18.24 18.32 18.42 18.80 18.92 19.00 19.12 19.77

P (mg/m3) 97547 80728 76099 74580 59268 57387 56388 54392 47088 45035 42857 39696 37885 37076 36010 35099 33189 32588 31824 29075 28259 27734 26956 23138

UR3 0.00 0.00 0.00 0.00 0.00 0.27 0.00 0.00 2.05 0.00 0.69 3.46 2.39 1.39 1.50 1.37 5.38 3.07 1.96 16.34 1.34 7.73 2.10 5.02

Material (mg) UR5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.24 0.00 0.00 0.00 3.62 1.17 2.00 2.07 6.60 2.77 0.00 25.36 2.50 5.59 1.79 3.71

Compound UR8 0.34 0.24 0.53 0.27 0.31 1.87 1.01 1.05 2.99 0.53 0.82 3.86 3.23 1.37 4.77 1.69 4.83 1.79 1.15 17.36 3.54 3.54 1.38 2.81

dimethyl cyclohexane isomer dimethyl cyclohexane isomer octane dimethyl cyclohexane isomer octene trimethyl cyclohexane isomer ethyl cyclohexane trimethyl cyclohexane isomer trimethyl cyclohexane isomer trimethyl cyclohexane isomer ethyl benzene xylene isomer trimethyl cyclohexane isomer trimethyl cyclohexane isomer trimethyl cyclohexane isomer trimethyl cyclohexane isomer ethyl methyl cyclohexane isomer ethyl methyl cyclohexane isomer xylene isomer nonane trimethyl cyclohexane isomer ethyl methyl cyclohexane isomer ethyl methyl cyclohexane isomer C10 branched hydrocarbon

2547 Appendix: Identification of VOCs their quantity in three materials (continued) GC RT (min) 19.92 20.12 20.30 20.39 20.79 20.91 21.12 21.18 21.28 21.40 21.52 21.81 21.81 21.96 22.06 22.14 22.60 23.42 23.49 23.60 23.75 24.61 24.63 24.74 24.87 25.09 26.10 26.55 26.69 27.01 27.11 27.31 27.57 27.75 28.06 29.35 32.92

P (mg/m3) 22298 21290 20362 19941 18167 17644 16799 16554 16174 15705 15250 14263 14236 13755 13420 13174 11815 9736 9576 9325 8997 7333 7304 7112 6901 6546 5154 4631 4479 4151 4054 3869 3635 3484 3234 2382 1023

UR3 9.51 15.81 4.64 9.89 0.00 9.86 9.38 12.36 10.34 3.29 9.30 0.00 2.84 6.42 7.80 3.05 48.96 9.08 2.66 3.23 5.45 2.51 3.03 2.90 4.71 3.55 16.64 1.01 1.40 0.79 0.00 0.64 0.00 0.00 0.59 1.60 0.85 280

Material (mg) UR5 9.85 16.82 3.82 7.53 1.08 11.39 7.59 8.76 7.69 0.00 7.05 1.32 0.00 6.07 6.73 3.70 35.35 14.00 2.80 4.03 7.10 5.11 4.63 4.06 5.97 4.55 15.56 1.71 2.33 1.31 1.15 1.20 0.00 0.00 0.99 2.19 0.00 272

Compound UR8 8.38 11.68 3.50 7.03 1.06 8.32 6.11 6.70 6.38 0.00 7.04 1.97 0.00 6.73 5.53 4.62 51.78 18.12 3.51 4.40 10.96 3.09 5.62 5.26 8.46 6.63 41.51 3.55 4.59 2.26 1.94 2.24 0.92 0.60 0.99 2.20 1.03 326

propyl cyclohexane C 10 branched hydrocarbon dimethyl ethyl cyclohexane isomer C10 branched hydrocarbon C4 cyclohexane isomer 1,1,2,3-tetramethyl cyclohexane mix of C3 benzene and C4 cyclohexane 4-methyl nonane 2-methyl nonane trimethyl benzene isomer 3-methyl nonane C4 cyclohexane isomer C3 benzene isomer+C4 cycohexane isomer methyl propyl cyclohexane methyl propyl cyclohexane methyl propyl cyclohexane decane 4-methyl decane (1-methylpropyl) cyclohexane C11 brached hydrocarbon butyl cyclohexane trans-decahydronaphthalene 5-methyl decane 4-methyl decane 2-methyl decane 3-methyl decane undecane methyl decahydronaphthalene CI i brached hydrocarbon C11 brached hydrocarbon methyl decahydronaphthalene pentyl cyclohexane dodecene dodecene C 11 brached hydrocarbon dodecane phthalic anhydride Total VOC