Passive Sampling Techniques Episode 4 pot

76 S. Wold, C. Albano, W.J. Dunn, U. Edlund, K. Esbensen, P. Geladi, S. Hellberg, E. Johansson, W. Lindberg and M. Sjo ¨ stro ¨ m, Multivariate Data Analysis in Chemistry. In: B.R. Kowalski (Ed.), Chemometrics: Mathe- matics and Statistics in Chemistry, D. Reidel Publishing Company, Dordrecht, Holland, 1984. 77 A L. Sunesson, C A. Nilsson and B. Andersson, J. Chromatogr. A, 699 (1995) 203. Passive sampling in combination with TD and GC to assess chemical exposure 83 Chapter 4 Use of permeation passive samplers in air monitoring Boz ˙ ena Zabiegała and Jacek Namies ´ nik 4.1 INTRODUCTION Passive sampling is now a well-established method to monitor pollution of air, especially indoor air [1–3]. Passive monitoring is generally char- acterized by the same accuracy as active monitoring, but an expensive sampling pump is not needed, which is very advantageous. Passive sampling offers considerable potential as a monitoring tool, especially for multi-point sampling over large, remote areas [2]. The only disad- vantage of permeation passive samplers seems to be relatively low sampling rates, which requires long sampling times in environments with low pollutant concentrations and the necessity to calibrate passive samplers for each substance due to distinguishing membrane charac- teristics [4]. However, long sampling times at low concentrations can also be viewed as an advantage of the permeation passive sampling, as it makes it easy to determine time-weighted average (TWA) concen- trations of analytes. In the overall assessment of the pollutant impact on human health, TWA concentrations are more useful than short-term concentrations, as they reflect the long-term exposure to these com- pounds. Permeation samplers, collecting gaseous pollutants at a rate controlled by permeation through a non-porous membrane, offer unique advantages, including effective moisture elimination and small sensitivity to air currents and temperature variations. In the case of indoor air quality measurements, they have the additional advantage of being much more acceptable by the inhabitants of the monitored areas compared to standard techniques based on dynamic sampling using sorption tubes. Comprehensive Analytical Chemistry 48 R. Greenwood, G. Mills and B. Vrana (Editors) Volume 48 ISSN: 0166-526X DOI: 10.1016/S0166-526X(06)48004-1 r 2007 Elsevier B.V. All rights reserved. 85 Chapter 5 Membrane-enclosed sorptive coating as integrative sampler for monitoring organic compounds in air Peter Popp, Heidrun Paschke, Branislav Vrana, Luise Wennrich and Albrecht Paschke 5.1 INTRODUCTION Membrane-enclosed sorptive coatings (MESCOs) are devices combining the advantages of passive sampling approaches with solvent-free pre- concentration of organic contaminants from air, water or other matri- ces. The sampling materials are polymer-coated stir bars, solid-phase microextraction (SPME) fibres or pieces of polymer materials. In 2001, Vrana et al. [1] first described an integrative passive sampler for mon- itoring organic contaminants in water. The authors used a stir bar coated with polydimethylsiloxane (PDMS) as described by Baltussen et al. [2] for the enrichment of the contaminants. The PDMS-coated stir bar (‘‘Twister’’) is then thermally desorbed on-line into a capillary gas chromatograph coupled with mass selective detector (GC–MS) system. The MESCO used for the first investigations consisted of a stir bar enclosed in a dialysis membrane bag made from regenerated cellulose, filled with double distilled water and sealed at each end with Spectra Por enclosures. Another MESCO type used for passive sampling of analytes from water consists of a low-density polyethylene (LDPE) tubing heat-sealed at both ends and filled with PDMS fibres and an inner fluid [3]. Independently from the devices designed for passive sampling in water (described in Chapter 10 of this book) two types of MESCOs for the long-term monitoring of semi-volatile organic air pollutants were also developed. Type A consists of an LDPE membrane tubing with Comprehensive Analytical Chemistry 48 R. Greenwood, G. Mills and B. Vrana (Editors) Volume 48 ISSN: 0166-526X DOI: 10.1016/S0166-526X(06)48005-3 r 2007 Elsevier B.V. All rights reserved. 107 TABLE 5.2 Calibration data for the investigated MESCO samplers: average concentration (C Air ) of the analytes during exposure and relative standard deviation (RSD), comparison between slope, axis intercept, coefficient of correlation (r 2 ) and uptake rate (R S ) Compound C Air (ng m À3 ) RSD (%) Slope (ng h À1 ) Intercept (ng) r 2 R S (mL h À1 ) Slope (ng h À1 ) Intercept (ng) r 2 R S (mL h À1 ) Sampler A1 Sampler A2 a-HCH 286 9.0 0.025 À1.16 1.00 88 0.180 À2.96 0.99 629 g-HCH 561 10.8 0.058 À3.76 1.00 104 0.439 À18.2 0.99 783 HCB 63 8.2 0.007 À0.22 1.00 108 0.045 À0.98 0.99 719 PCB 28 70 8.0 0.023 À0.83 0.99 321 0.304 À8.16 0.98 4314 PCB 52 96 5.5 0.022 À1.33 0.98 231 0.334 À15.6 0.98 3468 FLU 16 17.7 0.001 À0.04 0.98 70 0.048 À1.99 0.96 3006 Sampler B1 Sampler B2 a-HCH 149 3.5 0.068 À1.02 0.97 454 0.077 0.47 0.98 519 g-HCH 269 5.6 0.100 À0.02 0.96 372 0.137 2.93 0.99 511 HCB 282 12.1 0.025 À1.22 0.96 88 0.107 À3.77 0.99 379 PCB 28 109 5.9 0.060 À0.73 0.97 548 0.058 À0.15 0.98 537 PCB 52 171 3.6 0.208 À14.5 0.98 1216 0.091 À5.75 0.99 532 FLU 37 10.4 0.010 À0.87 0.94 263 0.010 À1.00 0.95 271 MESCO for monitoring organic compounds in air 115 . 1 04 0 .43 9 À18.2 0.99 783 HCB 63 8.2 0.007 À0.22 1.00 108 0. 045 À0.98 0.99 719 PCB 28 70 8.0 0.023 À0.83 0.99 321 0.3 04 À8.16 0.98 43 14 PCB 52 96 5.5 0.022 À1.33 0.98 231 0.3 34 À15.6 0.98 346 8 FLU. 231 0.3 34 À15.6 0.98 346 8 FLU 16 17.7 0.001 À0. 04 0.98 70 0. 048 À1.99 0.96 3006 Sampler B1 Sampler B2 a-HCH 149 3.5 0.068 À1.02 0.97 45 4 0.077 0 .47 0.98 519 g-HCH 269 5.6 0.100 À0.02 0.96 372. air [1–3]. Passive monitoring is generally char- acterized by the same accuracy as active monitoring, but an expensive sampling pump is not needed, which is very advantageous. Passive sampling