michel boutin, andré dufresne, - american industrial … · 2006-06-19 · michel boutin, andré...

May 17, 2006 1

Determination of Airborne IsocyanatesGenerated During the Thermal Degradation

of Car Paint in Body Repair Shops

Michel Boutin, André Dufresne,Claude Ostiguy, and Jacques Lesage

André Dufresne, MSc, PhD, CIHChemist, Associate Professor

e-mail: [email protected]

May 17, 2006 2

Plan

• 1) Introduction• 2) Objectives of the research work• 3) Material and methods• 4) Results• 5) Basis of interpretation• 6) Conclusions

May 17, 2006 3

Introduction (1)

• Polyurethanes are widely used in car paint formulations.

• During thermal degradation, such polymeric systems can generate powerful asthmatic sensitizing agents named isocyanates.(1)

(1) Karlsson et al., 2002; Pronk et al., 2005; Tinnerberg et al., 1997; Boutin et al., 2004, 2005

May 17, 2006 4

Introduction (2)

• In body repair shops, the thermal degradation of car paint can occur during abrasive processes that generate enough heat to involve isocyanatesrelease in air.(1)

(1) Henriks-Eckerman et al., 2002; Karlsson et al., 2000

May 17, 2006 5

Objective of the Research Work

• The purpose of this research was to use the high sensitivity and the high selectivity of LC/MS to quantify the greatest possible number of isocyanatesgenerated during the thermal degradation processes occurring in auto body shops and to evaluate the potential exposure of workers.

May 17, 2006 6

Material and Methods (1)

• Air measurements were performed at three different workplaces: two auto body repair training schools (A and B) and a body repair shop.

May 17, 2006 7

Material and Methods (2)C

uttin

g

Grin

ding

S

andi

ng

San

ding

May 17, 2006 8


• Green Honda Civic 2000 for school A,

• Grey Isuzu Rodeo 4WD 2001 for school B,

• Red Honda Civic 2000 for the body repair shop.

May 17, 2006 9

Material and Methods (4)• Two sampling systems were used:

– HSE (Cassette containing two MOPIP-coated filters and bubblers containing 15 mL of MOPIP in toluene);

– IRSST (Cassette containing two MOPIP-coated filters only (≈5 mg of MOPIP per filter) ).

R NCO +

Isocyanate MOPIP Urea

NNH

CH3O

R N C

H

O

N N

CH3O

May 17, 2006 10


• Source• Personal• Fixed station

May 17, 2006 11

Material and Methods (6)• Two LC/MSD Trap methods (I and II) were

needed to separate and analyze the MOPIP derivatives of the 18 isocyanates monitored during this study.(1)

• The instrumental detection limits (LOD) were in the 0.13-0.75 µg(NCO) / m3 range for 15 L air samples converted into 3 mL liquid samples.

(1) Boutin, M., (Post-Doc) Dufresne, A., Ostiguy, C., Lesage J. Determination of airborne isocyanates during the thermal degradation of car paint in body repair shops. Accepted in The Annals of Occupational Hygiene.

May 17, 2006 12

Basis of Interpretation

• Schedule 1 (Health & Safety Executive (UK) (HSE, 2005) of the Control of Substances Hazardous to Health (COSHH) Regulations specifies a Workplace Exposure Limit (WEL) of 20 µg / m3, 8-hour time-weighed average (TWA) reference period, for isocyanates in air.

• These limits are expressed as “weight of equivalent NCO groups”.

May 17, 2006 13

Results

May 17, 2006 14

0 10 20 30 40 50 60 Time (min)

1

2

3 4 5 6 7 8

9

1011 12

Rel

ativ

e In

tens

ity

0 10 20 30 40 50 60 Time (min)

1

2

3 4 5 6 7 8

9

1011 12

Rel

ativ

e In

tens

ity

LC/MSD Ion Trap chromatogram obtained using Method I; School A; Cutting process; Emission source;

HN

CO

-MO

PIP

Me-

i-MO

PIP

Et-i

-MO

PIP

Pro

pyle

ne-i-

MO

PIP

Pro

p-i-M

OP

IP

But

ylen

e-i-M

OP

IP

But

-i-M

OP

IP

Pen

tyle

ne-i-

MO

PIP

HD

I-MO

PIP

Pen

t-i-M

OP

IP

Hex

ylen

e-i-M

OP

IP

Hex

-i-M

OP

IP

May 17, 2006 15

10.0

2

Rel

ativ

e In

tens

ity

34

5

6

7

12.5 15.0 17.5 20.0 22.5 25.0 27.5 Time (min)

1

10.0

2

Rel

ativ

e In

tens

ity

34

5

6

7

12.5 15.0 17.5 20.0 22.5 25.0 27.5 Time (min)

1

LC/MSD Ion Trap chromatogram obtained using Method II; Body repair shop; Cutting process; Emission source;

2,6-

TDI-M

OP

IP

Ph-

i-MO

PIP

2,4-

TDI-M

OP

IP

p-To

l-i-M

OP

IP

cis-

IPD

I-MO

PIP

trans

-IPD

I-MO

PI

2,4’

-; 2,

2’an

d 4,

4’-M

DI-M

OP

IP

May 17, 2006 16

Results

• The highest isocyanate concentrations were observed during the cutting process.

May 17, 2006 17

Cutting Process(Source) (µg(NCO)m-3)

Hex-iPent-iBut-i

Prop-iEt-iMe-i

HDI

IDPI (trans,cis)

Aliphatic

ndnd0.30nd0.210.35

0.171.460.570.130.520.510.503.451.608.4976.844.1

2.092.0654.8

9.58ndnd

Shop (n=2)School B (n=4)School A (n=4)

May 17, 2006 18

Cutting Process(BZ) (µg(NCO)m-3)

Hex-i

Pent-i

But-i

Prop-i

Et-i

Me-IHDI

IDPI (trans,cis)Aliphatic

ndndnd

ndndnd

ndndnd

ndndnd

ndnd0.10

1.090.612.83

0.27nd1.86

1.36ndndShop (n=2)School B (n=4)School A (n=4)

May 17, 2006 19


0.270.151.42Hexylene-i

0.160.380.95Pentylene-i

0.190.430.49Butylene-i

0.421.951.52Propylene-i

Body Shop(n=2)

School B(n=4)

School A(n=4)

Alkenyl

May 17, 2006 20


ndndndHexylene-indndndPentylene-i

ndndndButylene-i

ndndndPropylene-i

Body Shop(n=2)

School B(n=4)

School A(n=4)

Alkenyl

May 17, 2006 21


27.071.169.1MDI(2,4’;2,2’;4,4’)

2.893.3112.82,4-TDI

0.09ND0.412,6-TDI0.210.560.57p-Tol-i

1.044.082.00Ph-i

Body Shop(n=2)

School B(n=4)

School A(n=4)

Aromatic

May 17, 2006 22


2.130.464.20MDI(2,4’;2,2’;4,4’)

0.44nd0.812,4-TDIndndnd2,6-TDIndndndp-Tol-i

ndndndPh-i

Body Shop(n=2)

School B(n=4)

School A(n=4)

Aromatic

May 17, 2006 23


53167192Total(aliphatic + alkenyl + aromatic)

61437165HNCO

Body Shop(n=2)

School B(n=4)

School A(n=4)

May 17, 2006 24


5.291.079.8Total(aliphatic + alkenyl + aromatic)

nd2.616.9HNCO

Body Shop(n=2)

School B(n=4)

School A(n=4)

May 17, 2006 25

Conclusion

May 17, 2006 26

Conclusion

• The isocyanate concentrations detected in the workers' breathing zone were in the range

– Cutting: 1.07-9.80 µg(NCO) / m3

– Grinding: 0.63-3.62 µg(NCO) / m3

– Sanding: 0-1.29 µg(NCO) / m3

May 17, 2006 27

Conclusion

• The isocyanate concentrations measured rapidly decreased from the emission source to the sampling tree, 2 m away.

• The use of posture, which maximizes the distance between the worker and the emission source could thus reduce significantly the isocyanate exposure.

May 17, 2006 28

Conclusion

• Near-instantaneous peak concentrations of isocyanates, which probably contribute more significantly to the development of asthma than chronic conditions, may exist.

michel boutin, andré dufresne, - american industrial … · 2006-06-19 · michel boutin, andré...

Documents