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Development and application of a needle trap device for time-weighted average diffusive sampling.

Analytical chemistry (2008-09-04)
Ying Gong, In-Yong Eom, Da-Wei Lou, Dietmar Hein, Janusz Pawliszyn
ABSTRACT

A simple, cost-effective analysis combining solventless extraction, thermal desorption, and determination of volatile organic compounds (VOCs) was developed and validated. A needle trap device (NTD) packed with the sorbent Carboxen1000 was used as a time-weighted average (TWA) diffusive sampler to collect target compounds by molecular diffusion and adsorption to the packed sorbent. This process can be described with derivations of Fick's first law of diffusion, which expresses the relation between the TWA concentrations to which the passive sampler is exposed and the mass of analytes adsorbed to the packed sorbent in the sampler. The effects of experimental factors such as temperature, pressure, humidity, and face velocity were taken into account in applying diffusive sampling under nonideal conditions. This study demonstrates that NTD is effective for air analysis of benzene, toluene, ethylbenzene, and o-xylene (BTEX), due to the good adsorption/desorption quality of Carboxen 1000 and to the special geometric shape of the needle with a small cross section avoiding the need for calibration. Storage tests showed good storage stability for BTEX. Verification of the theoretical model showed good agreement between theoretical and experimental sampling rates. Method validation done against NIOSH method 1501, SPME, and NTD active sampling revealed good agreement between those methods. Automated NTD sample introduction to a gas chromatograph facilitates the use of this technology for industrial hygiene applications.

MATERIALS
Product Number
Brand
Product Description

Supelco
Tenax® TA / Carboxen® 1018, glass TD tube, preconditioned, O.D. × L 1/4  in. × 3 1/2  in., Sealed with (Swagelok® End-Fittings), pkg of 10 ea
Supelco
Carboxen®-1010 PLOT Capillary GC Column, L × I.D. 30 m × 0.53 mm, average thickness 30 μm
Supelco
Carboxen® Adsorbent, matrix Carboxen® 569, 20-45 mesh, bottle of 10 g
Supelco
ORBO 78 HBr on Carboxen® 564 specially cleaned (20/45), 400/200 mg, W,W,W separators, O.D. × L 6 mm × 110 mm, pkg of 25 ea
Supelco
Carboxen®-1006 PLOT Capillary GC Column, L × I.D. 30 m × 0.53 mm, average thickness 30 μm
Supelco
Carboxen® Adsorbent, matrix Carboxen® 1000, 60-80 mesh, bottle of 10 g
Supelco
ORBO 90 Carboxen® 564 (20/45), 160/80 mg, W,F,F separators, O.D. × L 6 mm × 75 mm, pkg of 25 ea, for analyte group MEK (methylethyl ketone)
Supelco
Carboxen®-1010 PLOT Capillary GC Column, L × I.D. 30 m × 0.32 mm, average thickness 15 μm
Supelco
Carboxen® Adsorbent, matrix Carboxen® 569, 20-45 mesh, bottle of 500 g
Supelco
Carboxen®-1006 PLOT Capillary GC Column, L × I.D. 30 m × 0.32 mm, average thickness 15 μm
Supelco
Carboxen® Adsorbent, matrix Carboxen® 1003, 40-60 mesh, bottle of 10 g
Supelco
Carboxen® Adsorbent, matrix Carboxen® 1000, 40-60 mesh, bottle of 50 g
Supelco
Carboxen® Adsorbent, matrix Carboxen® 563, 20-45 mesh, bottle of 10 g
Supelco
Carboxen® Adsorbent, matrix Carboxen® 564, 20-45 mesh, bottle of 10 g
Supelco
Carboxen® 1000 Reversible SPE Tube, 200 mg/mL, pk 30
Supelco
Carboxen® 572 for Tobacco Smoke, Adsorbent Bed Wt: (300 mg), cartridge volume 3 mL, pkg of 10 ea
Supelco
ORBO-93 Sorbent Tube, matrix Carboxen® 1000, ORBO tube I.D. × L 6 mm × 95 mm, Bed B 90 mg, Bed A 180 mg, 60/80 mesh, pkg of 25 ea
Supelco
SPME fiber assembly Carboxen/Polydimethylsiloxane (CAR/PDMS), df 75 μm (CAR/PDMS), for use with manual holder, needle size 24 ga
Supelco
SPME fiber assembly Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS), needle size 24 ga, for use with manual holder
Supelco
Carboxen® 569, O.D. × L 1/4  in. × 3 1/2 , glass TD tube, fritted, Sealed with Brass Endcaps, preconditioned, pkg of 10 ea
Supelco
Carboxen® 572 for Tobacco Smoke, Adsorbent Bed Wt: 300 mg, cartridge size 3 mL, pkg of 50 ea
Supelco
SPME fiber assembly Carboxen/Polydimethylsiloxane (CAR/PDMS), df 75 μm (CAR/PDMS), needle size 23 ga, for use with manual holder
Supelco
SPME fiber assembly Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS), needle size 24 ga, StableFlex, for use with manual holder/autosampler
Supelco
Carboxen® 569, glass TD tube, fritted, O.D. × L 1/4  in. × 3 1/2  in., preconditioned, pkg of 10 ea
Supelco
Carboxen® Adsorbent, matrix Carboxen® 564, 20-45 mesh, pack of 144 × 290 mg
Supelco
SPME fiber assembly Carboxen/Polydimethylsiloxane (CAR/PDMS), df 75 μm (CAR/PDMS), needle size 24 ga, for use with autosampler
Supelco
SPME fiber assembly Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS), needle size 24 ga, StableFlex, for use with autosampler
Supelco
SPME fiber assembly Carboxen/Polydimethylsiloxane (CAR/PDMS), df 75 μm (CAR/PDMS), needle size 23 ga, for use with autosampler
Supelco
SPME fiber assembly Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS), needle size 23 ga, StableFlex, for use with manual holder/autosampler, fiber L 2 cm
Supelco
SPME fiber assembly Carboxen/Polydimethylsiloxane (CAR/PDMS), df 85 μm (CAR/PDMS), needle size 24 ga, for use with manual holder, StableFlex fiber