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Evaluation of a Device for Preparing Calibrated Air Sampling Tubes That Mimics Real Air Sampling Conditions
Poster Presentation
Prepared by K. Stenerson1, J. Brown2, J. Brown3, O. Shimelis4, G. Oishi5
1 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
2 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
3 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
4 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
5 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
Contact Information: katherine.stenerson@sial.com; 814-359-3441
ABSTRACT
Spiking calibration standards onto air sampling tubes in order to generate calibration curves and conduct desorption efficiency and breakthrough studies can be a difficult task. One approach is to inject a liquid standard directly onto sample media using a micro-syringe. However, this technique has a major drawback; the compounds in the calibration standard are dispensed in the liquid form, which does not realistically mimic how the real air samples are taken. For example, in a multi-bed thermal desorption tube if spiking is done directly onto the first adsorbent bed (which is the weakest), some of the compounds in the calibration standard will never be exposed to the later beds, which contain the stronger adsorbents. In a real situation, some compounds always move from the first bed into subsequent beds while sampling is taking place.
Ideally, when preparing calibration standards, the spiking technique used should mimic conditions in which the air sample was taken in the field. A sample prep device, known as ATIS which stands for "adsorbent tube injection system" was specifically designed for the task of spiking air sampling tubes. It incorporates the technique of “flash vaporization” to completely vaporize a liquid calibration standard and transfer it to sampling media, mimicking the behavior of real air samples. The device consists of injection glassware housed in an aluminum block that heats to vaporize the calibration standard. A stream of gas flowing through the injection glassware carries the vaporized compounds onto an adsorbent tube which is attached to the device. The research presented will demonstrate the use of the ATIS, compare the reproducibility of different spiking techniques, and illustrate the different factors that can affect accuracy and precision.
(Related Session: Air Methods/Monitoring)
Poster Presentation
Prepared by K. Stenerson1, J. Brown2, J. Brown3, O. Shimelis4, G. Oishi5
1 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
2 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
3 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
4 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
5 - Sigma-Aldrich/Supelco, 595 Harrison Road, Bellefonte, PA, 16823
Contact Information: katherine.stenerson@sial.com; 814-359-3441
ABSTRACT
Spiking calibration standards onto air sampling tubes in order to generate calibration curves and conduct desorption efficiency and breakthrough studies can be a difficult task. One approach is to inject a liquid standard directly onto sample media using a micro-syringe. However, this technique has a major drawback; the compounds in the calibration standard are dispensed in the liquid form, which does not realistically mimic how the real air samples are taken. For example, in a multi-bed thermal desorption tube if spiking is done directly onto the first adsorbent bed (which is the weakest), some of the compounds in the calibration standard will never be exposed to the later beds, which contain the stronger adsorbents. In a real situation, some compounds always move from the first bed into subsequent beds while sampling is taking place.
Ideally, when preparing calibration standards, the spiking technique used should mimic conditions in which the air sample was taken in the field. A sample prep device, known as ATIS which stands for "adsorbent tube injection system" was specifically designed for the task of spiking air sampling tubes. It incorporates the technique of “flash vaporization” to completely vaporize a liquid calibration standard and transfer it to sampling media, mimicking the behavior of real air samples. The device consists of injection glassware housed in an aluminum block that heats to vaporize the calibration standard. A stream of gas flowing through the injection glassware carries the vaporized compounds onto an adsorbent tube which is attached to the device. The research presented will demonstrate the use of the ATIS, compare the reproducibility of different spiking techniques, and illustrate the different factors that can affect accuracy and precision.
(Related Session: Air Methods/Monitoring)