8/3/2019 Screenings or Bent Tubes

http://slidepdf.com/reader/full/screenings-or-bent-tubes 1/2

SKC Inc. 724-941-9701 SKC West 714-992-2780 SKC Gulf Coast 281-859-8050 SKC South 434-352-7149

www.skcinc.com

Screening Sorbent TubesPublication 1362 Rev 0401

Multiple Sorbents for Multiple Contaminants

Description Designed to collect a wide array of compounds, SKC thermal

desorption screening tubes contain multiple layers of different

sorbent materials. This specialized construction allows for the

collection of different classes of compounds including both

polar and non-polar compounds in the C2

to C30

range to be

collected with one tube. After identifying the contaminants,

further sampling using methods for specific compounds can be

used for quantification.

• Cost-effective• One inexpensive and highly sensitive tube screens for

many compounds

• Time-saving• Quickly determine what compounds are present

• Sampling for multiple compounds in unknown

atmospheres

• Hydrocarbons, alcohols, aromatics, aldehydes, sulfides,ketones, esters, and halogenated compounds

• Tubes can be used with a personal sampling pump

• Wide range of monitoring applications

Applications • Workplace background exposure levels

• Personal exposure levels

• Unknown atmospheres

• Sick Building Syndrome (SBS)

• Process changeover/maintenance exposures

• Confined areas• Stack emissions/vent gases

• HazMat

Methods for Screening Tubes 

  NIOSH Method 2549†  is a screening method for sampling

volatile organic compounds (VOCs) in the C5

to C16

range.

VOCs are sampled by drawing air through the sorbent tube using

a personal sampling pump at a flow rate of 50 ml/min. Analysis

is by thermal desorption/gas chromatography-mass spectrom-

etry (TD/GC-MS). NIOSH 2549 specifies a thermal desorptiontube containing sorbent layers of graphitized carbon and carbon

molecular sieve (CMS), but allows other sorbent combinations

to be used. In particular, if the compounds of interest are known,

specific sorbents that work best for those compounds may be

substituted.

† NIOSH Manual of Analytical Methods, Fourth Edition, May 15, 1996

 EPA Method IP-1B* applies to sampling a variety of VOCs

having a boiling point range of approximately 80 to 200 C. The

VOCs are sampled by drawing indoor air through the sorbent

tube using a personal sampling pump at a flow rate of 12 to 150

ml/min depending on the compound. Analysis is by TD/GC-MS. EPA IP-1B specifies a thermal desorption sorbent tube

containing Tenax®, but also includes an alternative multi-bed

sorbent tube containing CMS and graphitized carbon.

* Compendium of Methods for the Determination of Air Pollutants in Indoor

 Air (EPA/600/4-90/010 April, 1990)

The TDT Air Scan™ screening tube was developed using a

combination of instrument technology and methodology. De-

signed to trap both polar and non-polar compounds in air, this

multi-bed sorbent tube containing CMS, graphitized carbon,

and Tenax GR can be used for the qualitative identification of 

multiple compounds. The analytical method is used to deter-mine what compounds are present as well as what compounds

are not. Samples are taken using a personal sampling pump. For

analysis using Prism Analytical's sensitive analytical technique,

the tube must be sent to Prism Analytical, Inc., 1200 N. Fancher,

Mt. Pleasant, MI 48858, (989-772-5088).

8/3/2019 Screenings or Bent Tubes

http://slidepdf.com/reader/full/screenings-or-bent-tubes 2/2

 Notice: This publication is intended for general information only and should not be used as a substitute for reviewing applicable government regulations, equipmentoperating instructions, or legal standards. The information contained in this document should not be construed as legal advice or opinion nor as a final authority on legalor regulatory procedures.

Screening Sorbent Tubes

SKC Inc. 724-941-9701 SKC West 714-992-2780 SKC Gulf Coast 281-859-8050 SKC South 434-352-7149

www.skcinc.com

Multiple Sorbents for Multiple Contaminants

Applications Sorbent

(Amount) Description Desorber Cat. No.

EPA IP-1B, Anasorb CMS/GCB1/ GCB2 Glass, open Dynatherm 226-330*

NIOSH 2549 (100 mg/150 mg/250 mg) 6-mm OD x 115-mm L

EPA IP-1B, Anasorb CMS/GCB1/ GCB2 Stainless steel, open Tekmar 226-338*

NIOSH 2549 (125 mg/200 mg/300 mg) 1/4-in OD x 7-in L

Screening Multiple Anasorb CMS/GCB1/ Tenax GR Glass, open # 226-352*

Compounds (100 mg/100 mg/100 mg) 1/4-in OD x 4 1/2-in L

# Proprietary method for analysis by thermal desorption using a sensitive analytical technique developed by Prism Analytical Technologies, Inc, call 989-772-5088.* Tubes must be conditioned before use and used within 30 days. SKC offers conditioned tubes; contact SKC for more information.

Custom Screening Tubes SKC currently manufactures the sorbent combinations listed

below as standard items, but specialty tubes can be made for

custom applications or different thermal desorbers.

Developments in sorbent technology have brought about supe-

rior materials for the collection of VOCs in the environment.

SKC sorbent materials meet stringent specifications and un-

dergo extensive cleaning procedures required for screening tube

applications.

Sorbents Used in Screening Tubes  Anasorb® CMS (Carbon Molecular Sieve) is a traditional

sorbent for trapping low boiling point compounds (-60 to 80 C)

in the C2

through C5

range. CMS is comparable to Carbosieve®

S-III and Carboxen® 1000 and 1003.

 Anasorb GCB1 (Graphitized Carbon Black 1) is a sorbent for

sampling intermediate to highly volatile compounds (bp > 75C)

in the C5

through C14

range. It is equivalent to Carbotrap® B.

 Anasorb GCB2 (Graphitized Carbon Black 2) is a sorbent for

sampling semi-volatile compounds in the C8through C

20range.

It is equivalent to Carbotrap C.

Tenax GR is a 70% Tenax TA/30% graphite composite sorbent

for trapping low, medium, and high boiling point compounds

(bp 100 to 450 C) in the C7 through C30 range.

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(Refer to the method forspecific compound listings)

Ordering Information