Recent Developments in Catbonyl Sampling & Analysis · Recent developments in Carbonyl Sampling and...

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Recent developments in Carbonyl Sampling and AnalysisFrank [email protected]


Sources of carbonyl compounds

Anthropogenic sources• Outdoor

– Industrial processes– Combustion of fossile fuels

– Car exhaust– Heating, energy

• Indoor– Release from fabrics e.g. carpets, wooden furniture,ceiling tiles– Smoking

Biogenic sources• Plants

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Importance of monitoring carbonyls

Adverse effect on human health (acute and chronic) [1]• Eye and lung irritation• Formaldehyde is a suspected carcinogen• Photochemical smog [2]

• [1] Altshuller A. P., J Atmos Chem, 1978, 28: 594–598• [2] "What is Smog?", Canadian Council of Ministers of the Environment

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First approach for carbonyl analysis: Impingers

Derivatizationreagent solution containing• 2,4-Dinitrophenylhydrazin (DNPH) [3]• 2,3,4,5,6-Pentafluorbenzylhydroxylamin (PFBHA)• 2-AminoethanthiolDetection by HPLC/UV or fluorescence

Disadvantages:• Quantitation (need to use in series, evaporated solvent)• Inconvenient• Not robust• Dealing with liquid solution in the field

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[3] D. Grosjean, Environ. Sci. Technol. 16 (1982) 254


State of the Art: Coated Adsorbents

Derivatization Reagent• 2,4-Dinitrophenylhydrazine (DNPH)

• 5-Dimethylaminonaphtalenesulfonic acid hydrazine (Dansylhydrazine, DNSH)

• N-Methyl-2,4-dinitrophenylhydrazine (MDNPH) [4]• 2-(Hydroxymethyl)piperidine• 2,4,6-Trichlorophenylhydrazine• 2,3,4,5,6-Pentafluorobenzylhydroxylamine (PFBHA)

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O2N

NO2

NH

NH2

CH3

S

O

O

NH

NH2

[4] A. Bueldt, U. Karst, Anal. Chem. 1997, 69, 3617-3622


DNPH Derivatization of Carbonyls [5,6]

NO2

O2N

NHNH2

R'

O

R

H+

-H2O

NO2

O2N

NHN

R'R

+

DNPH derivative(a hydrazone)• Stable• UV detection[5] C.F.H. Allen, J. Am. Chem. Soc. 52 (1930) 2955

[6] Beasley R. K. et al.; Anal. Chem., 1980, 52, 1110-1114


Isomerization Possible

Only non-symmetric carbonyl compounds (R ≠ R‘)Might occur by UV radiation or acidic catalysis [7]Usually only E isomer is observed

7

NO2

O2N

NHN

HCH3

NO2

O2N

NHN

CH3H

Z isomer E isomer[7] S. Uchiyama et al., J. Chromatog. A 996 (2003) 95-102

R'

O

R


Isomerization Possible

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Instrument: Shimadzu HPLC/UVDet.: 360 nmCol.: Discovery RP-Amide C16,

250 x 4.6 mm, 5 µm Mob. Phase: acetonitrile/water. Gradient:Time (min) 0 5 25 40 60Acetonitrile (%) 40 40 58 70 70Flow-rate: 1.5 ml/minTemp: 40 °CInj. Volume: 20 ml

Sample A: Solution of the E isomers ofDNPH hydrazones of C1 - C10aldehydes (50 µmol/L)

Sample B: Solution of sample A after addition of phosphoric acid

[7] S. Uchiyama et al., J. Chromatog. A 996 (2003) 95-102


Potential Interferences

Ozone O3• Formation of several products [8,9]Nitrogen oxides NOX• React to 2,4-dinitrophenyl azide (may eliminate N2 and react further

to 5-nitrobenzofurazan 3-oxide under cyclization) [10]Coelution of by-products with the hydrazones possible• Dual-wavelength detection for peak purity from by-products [11]

• [8] Arnts, R. R.; Tejada, S. B. Environ. Sci. Technol. 1989, 23, 1428-1430.• [9] Smith, D. F.; Kleindienst, T. E.; Hudgens, E. E. J. Chromatogr. 1989, 483, 431-436.• [10] Karst, U. et al., U. Fresenius J. Anal. Chem. 1993, 345, 48-52.• [11] Poetter, W.; Karst, U. Anal. Chem. 1996, 68, 3354-3358.

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O2N

NO2

N3


Sampling and Work-up

•Sampling Elution

ManualAutomated &

on-line with HPLC [12]

e.g. Anatune 300 for S10 cartridges

ExampleLpDNPH S10 Cartridge

[12] The Reporter Vol. 53, Feb. 2013


Overview on LpDNPH CartridgesName Carbonyl capacity (FA) Specials

S10 <75 μgS10L <75 μg Shorter dimensions, no adapterS10x <75 μg For automated handlingRezorian™ <75 μg Luer lock syringe connections

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Rezorian54074-U, 54075-U


Overview on LpDNPH CartridgesName Carbonyl capacity (FA) Specials

H Series H10: >75 - 225 μgH30: >225 - 643 μgH300: >643 - 6400 µg

Higher loadings of DNPH and bed weights

ORBO™-555 75 - 225 μg 300 mg/150 mg, to detect breakthrough

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54020-U ORBO-555 DNPH Tube


Rezorian S10L

Mean (inches water) 2.4 9.9

Range (inches water) 2.2 – 2.6 6.7 – 14.9

Standard Deviation 0.12 2.57

Sample Size (n) 10 10

The conical shape of the Rezorian cartridge results in unobstructed air flow through the bottom frit.

Pressure Drop at 200mL/min Air Flow


High Purity DNPH Packing

•Reproducible low background of DNPH to meet specification

•Purified reagents to needed level (cleanup)

•Use of clean solvents


Time (days)0 20 40 60

Form

alde

hyde

(ng)

0

20

40

60

Rezorian - Refrigerated

Rezorian - Room Temperature

S10L Refrigerated

S10L Room Temperature

Storing DNPH cartridges:Changes in Formaldehyde Background


Time (days)0 20 40 60

Ace

tald

ehyd

e (n

g)

0

20

40

60

80Rezorian - Refrigerated

Rezorian - Room Temperature

S10L - Refrigerated

S10L - Room Temperature

Storing DNPH cartridges:Changes in Acetaldehyde Background

Concerns for a reliable result:• Temperature• UV Light


BPE-DNPH Cartridges

trans-1,2-Bis(2-pyridyl)ethylene (BPE)

•Determination of carbonyls without ozone interference•Parallel Determination of Carbonyls & Ozone•No need for a separate ozone scrubber

– BPE works as a scavenger for ozone (more effective than others)

•Suitable for high humidity conditions•BPE-DNPH 90/260 mg


BPE-DNPH - Reaction Principle

Elution: Ozone & Carbonyl derivatives ACN/DMSO, 75/25 v/v, 3mLCarbonyls derivatives only ACN

O+

O O-

N

N

H

H

H2O

N

O

H

2 + H2O2+

DNPH

O2N

NO2

NH

NH2R'

O

R

+H

+

O2N

NO2

NH

N

R'

R + H2O

trans-1,2-Bis(2-pyridyl)ethylene (BPE) Pyridine-2-aldehyde

DNPH


BPE-DNPH - Result Column: Ascentis C18, 150 x 4.6 mm, 5 μmMobile phase: 35/65 acetonitrile/2 mM ammonium acetate

(10 min.), gradient to 75% acetonitrile at 25 min. (5 min. hold)

Flow rate: 1.9 mL/min.Det.: UV 360 nmInjection: 20 μL

1. Formaldehyde-DNPH2. Pyridine-2-aldehyde-DNPH3. Acetaldehyde-DNPH4. Acetone-DNPH

Air Sample

Cartridge blank

Note: Pyridine-2-aldehyde-DNPH Standard available as Prod. Nr. 40117-U


Determination of Ozone in Chiba City, Japan [13]

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Slope = 1.01R2 = 0.99

2-BPE/DNPH Method (ug/m3)0 20 40 60 80 100 120 140

Air

Mon

itorin

g S

tatio

n (u

g/m

3 )

0

20

40

60

80

100

120

140

(µg/m3)

(µg/

m3

)

[13] S. Uchiyama et al., Anal. Chem. 2009, 81, 6552-6557


Passive Sampling of Carbonyl Compounds

radiello® - radial diffusive sampler• sampling rates similar to active sampling

– for formaldehyde 99 mL/min – for acetaldehyde 84 mL/min

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• Adsorbent Cartridge• 2,4-DNPH coated Florisil• Supplied in storage container

• Diffusive Body• Blue diff. body

• Support plate• Triangular back plate• With pouch for barcode label


Analysis of Hydrazones (DNPH derivatives)

GC• Limited due to degradation of hydrazones of larger carbonyls• Smaller carbonyls exhibit an incresed baseline between syn- and anti

isomers, maybe due to conversion of isomers• Excess of DNPH might need to be removed before analysis (for ECD)• Detection by FID, ECD or MS

HPLC (approx. 70 %)• Often C18• Critical: C3 Carbonyl components (propanal, acrolein, acetone) co-elute

on many columns• Isomers usually not separated• UV Detection @ 340-380 nm; Interferences: dual-wave length detection

at 300 nm [11]

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© 2012 Sigma-Aldrich Co. All rights reserved. 24

0 2 4 6 8 10 12Time (min)

020

4060

8010

012

014

0m

AU

0 2 4 6 8 10 12Time (min)

020

4060

8010

012

014

0m

AU

Column: 150 x 4.6 mm I.D.Mobile phase:

Ascentis Express C18: 2.7 µm: 25:75, water: acetonitrileAscentis C18 : 3 µm: 30:70, water: acetonitrile

Flow rate: 1.0 mL/min.Temp.: 30 °CDet.: UV at 365 nmInjection: 1 µLSample: 47285-U TO11/IP6A Carbonyl-DNPH Mix

as indicated below in 40:60, water: acetonitrile

Peak IDs

1. Formaldehyde-2,4-DNPH (105 µg/mL)2. Acetaldehyde-2,4- DNPH (76.4 µg/mL)3. Acrolein-2,4- DNPH (63.2 µg/mL)4. Acetone-2,4- DNPH (61.5 µg/mL)5. Propionaldehyde-2,4- DNPH (61.5 µg/mL)6. Crotonaldehyde-2,4- DNPH (53.6 µg/mL)7. Butyraldehyde-2,4- DNPH (52.5 µg/mL)8. Benzaldehyde-2,4- DNPH (40.5 µg/mL)9. Isovaleraldehyde-2,4- DNPH (46.4 µg/mL)10. Valeraldehyde-2,4- DNPH (46.4 µg/mL)11. o-Tolualdehyde-2,4- DNPH (37.5 µg/mL)12. m-Tolualdehyde-2,4- DNPH (37.5 µg/mL)13. p-Tolualdehyde-2,4- DNPH (37.5 µg/mL)14. Hexaldehyde-2,4- DNPH (42 µg/mL)15. 2,5-Dimethylbenzaldehyde-2,4- DNPH (35 µg/mL)

Ascentis Express C18, 2.7 µmPeak 8N = 260,720 p/mN = 39,108 p/col

Ascentis C18, 3 µmPeak 8N = 146,587p/mN = 21,988p/col

TO11/IP6A Carbonyl DNPH Mix

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8

Sensitivitygap


Alternative stationary phase for DNPHydrazones

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Column: Ascentis RP-Amide, 250 x 4.6 mm, 5 μmMob. phase A: 60:40, water:acetonitrileMob. phase B: 25:75, water:acetonitrileFlow rate: 1.5 mL/min.temp.: 40 °Cdet.: UV at 360 nminjection: 10 µl

Gradient: Min %A %B0 100 05 100 025 40 6040 0 10060 0 100

4. Acetone-2,4-DNPH5. Acrolein-2,4-DNPH6. Propionaldehyde-2,4-DNPH


LpDNPH S10 Cartridge – Laboratory Air Sample

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Column: Ascentis Express C18, 150 x 4.6 mm, 2.7 μmMobile phase A: Water Mobile phase B: Acetonitrile Flow rate: 0.5 mL/min Temp.: ambient Det.: UV at 360 nm Injection: 10 μL

Gradient: Min %A %B0 45 55 4 45 55

13 10 90 20 10 90

1. Formaldehyde-DNPH 2. Acetaldehyde-DNPH 3. Acetone-DNPH


Summary

Analysis of Carbonyl Compounds• Derivatization with DNPH on coated sorbent tubes is State of the Art• Different options for different purposes

– active/passive sampling, – manual/automated work-up– wide concentration range (low to high concentrations) – stacking of cartridges

• Interference by ozone can be circumvented by BPE-DNPH• Analysis by HPLC

– Use of high efficiency column for more sensitive and/or faster results– Alternative phase selectivities provide better separation


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