SPMDs devices

XAD-2010, 1180 Vacuum manifold and accessories SPMD devices polydimethylsiloxane... 

LLE, liquid-liquid extraction MAE, microwave-assisted extraction SEE, solid-phase extraction SPME, solid-phase microextraction LPME, liquid-phase microextraction SOME, single-drop microextraction D-LLLME, dynamic liquid-liquid-liquid microextraction SEE, supercritical fluid extraction MIP, molecularly imprinted polymers sorbent SPMD, device for semipermeable membrane extraction PDMS, polydimethylsiloxane coated fiber PA, polyacrylate coated fiber CW-DMS, Carbowax-divinylbenzene fiber PDMS-DVB, polydimethylsiloxane divinylbenzene fiber CAR-PDMS, Carboxen-polydimethylsiloxane coated fiber DVB-CAR-PDMS, divinylbenzene Carboxen-polydimethylsiloxane coated fiber CW-TPR, Carbowax-template resin HS-SPME, headspace solid-phase microextraction MA-HS-SPME, microwave-assisted headspace-solid-phase microextraction HEM, porous hollow fiber membrane PEl-PPP, polydydroxylated polyparaphenylene. 

Figure 7. Dialysis extraction of PAFls contained in SPMDs devices.

Table 11 summarizes the main applications of conventional dialysis in the extraction of SPMDs devices used in air monitoring of PAHs. It can be observed that, in all cases, extraction times of 48 h, and organic solvent volumes higher than 200 mL, are required. 

USE OF SEMI PERMEABLE MEMBRANE DEVICES (SPMDs) TO INDOOR AIR MONITORING OF PYRETHROID INSECTICIDES... 

The most widely employed techniques for the extraction of water samples for triazine compounds include liquid-liquid extraction (LLE), solid-phase extraction (SPE), and liquid-solid extraction (LSE). Although most reports involving SPE are off-line procedures, there is increasing interest and subsequently increasing numbers of reports regarding on-line SPE, the goal of which is to improve overall productivity and safety. To a lesser extent, solid-phase microextraction (SPME), supercritical fluid extraction (SEE), semi-permeable membrane device (SPMD), and molecularly imprinted polymer (MIP) techniques have been reported. 

Prest, H.F., W.M. Jarman, S.A. Bums, T. Weismuller, M. Martin, and J.N. Huckins. 1992. Passive water sampling via semipermeable membrane devices (SPMDs) in concert with bivalves in the Sacramento/San Joaquin river delta. Chemosphere 25 1811-1823. 

Due to the predicted and previously detected low concentrations of pesticides in environmental samples (usually around the nanogram per liter level), a preconcentration step of the water samples is necessary prior to measurement. In this way, a preconcentration factor of several orders of magnitude (200-1,000-fold) is mandatory to reach the low detection limits necessary for the identification of pesticides, especially in complex wastewater samples. Also, the use of surrogate standards (e.g., triphenyl phosphate) added before the extraction step is a common practice in order to account for possible errors during the extraction process and for quantitative purposes. The commonly used extraction methods for polar compounds from water matrices involve isolation using liquid-liquid extraction (LLE) and solid-phase extraction (SPE), which are commented on below. Other methods such as semipermeable membrane devices (SPMD) are also mentioned. 

Petty JD, Huckins JN, Martin DB. 1995. Use of semipermeable membrane devices (SPMDS) to determine bioavailable organochlorine pesticide residues in streams receiving irrigation drainwater. Chemosphere 30(10) 1891-1903. 

In the following sections we highlight only selected works that have contributed toward the further development of passive samplers for SVOCs and/or HOCs. The literature related to the development and use of passive samplers for monitoring gases or VOCs in occupational environments is large. However, these publications are discussed only briefly, because lipid-containing semipermeable membrane devices (SPMDs) are primarily designed for SVOCs. 

PESs by the end of the exposure. Differences in exposure concentrations did not affect the sampling rates of PESs, which indicate that these devices obey first-order uptake kinetics. The sampling rate of " C-2,2 ,5,5 -TCB by PESs (4.8 L d ) was similar to that observed for 1 mL triolein SPMDs, with the same surface area. 

Table 1.1 compares key aspects and performance characteristics of selected passive samplers, including the triolein-containing SPMD. Of the eight devices examined, only a few appear to have overlapping functions. Clearly, no one device can provide the desired data for all exposure scenarios. 

Lipid-Containing SPMDs and Closely Related Devices... 

Based on earlier work (Lieb and Stein, 1969 Chiou, 1985 Sddergren, 1987 Zabik, 1988) Huckins etal. (1989,1990a, 1993) flrstdeveloped and tested two types of lipid-containing semipermeable membrane devices (SPMDs) for in situ passive sampling of bioavailable dissolved aqueous-phase HOCs. The lipid-containing... 

Huckins, J.N. Petty, J.D. Prest, H.F. Clark, R.C. Alvarez, D.A. Orazio, C.E. Lebo, J.A. Cranor, W.L. Johnson, B.T. 2002a, A Guide for the Use of Semipermeable Membrane Devices (SPMDs) as Samplers of Waterborne Hydrophobic Organic Contaminants Publication No. 4690 American Petroleum Institute (API) Washington, DC. 

Petty, J.D. and Orazio, C.E. 1996, Application of Semipermeable Membrane Devices (SPMDs) Ay Passive Monitors of the Environment of Antarctica. USGS, Midwest Science Center, Columbia, MO Unpublished report to National Science Foundation Washington, DC. 

Rantalainen, A.-L. Ikonomou, M.G. Rogers, I.H. 1998, Lipid-containing semipermeable-membrane devices (SPMDs) as concentrators of toxic chemicals in the Lower Fraser River, British Co mAA2LCheniosphere 37 1119—1138. 

All passive monitoring devices operate on the basis of diffusive transfer, regardless of whether they are classified as diffusion, permeation or unclassified (e.g., SPMDs), and the rate-limiting barrier is the step with the greatest resistance to mass transfer (see Figure 3.1). Pick s first law is the fundamental law of diffusion. It states that the flux of a chemical in the x-direction (j , e.g., ng cm d ) is proportional to the concentration gradient (9C/9x)... 

Bartkow, M.E. Huckins, J.N. Muller, J.F. 2004, Field-based evaluation of semipermeable membrane devices (SPMDs) as passive air samplers of polyaromatic hydrocarbons (PAHs). Atmos. Errviron. 38 5983-5900. 

Ellis, G.S. Huckins, J.N. Rostad, C.E. Schmitt, C.J. Petty J.D. MacCarthy, P. 1995, Evaluation of lipid-containing semipermeable membrane devices (SPMDs) for monitoring organochlorine contaminants in the Upper Mississippi River. Environ. Toxicol. Cherrc 14 1875-1884. 

Sampling rates for the case of total boundary layer-control can be expected to be nearly independent of temperature, since both the diffusion coefficients in air, and the kinematic viscosity of air are only weak functions of temperature (Shoeib and Harner, 2002). This leaves the air-flow velocity as the major factor that can be responsible for the seasonal differences among sampling rates observed by Ockenden et al. (1998). The absence of large R differences between indoor and outdoor exposures may be indicative of membrane-control, but it may also reflect the efficient damping of high flow velocities by the deployment devices used for SPMD air exposures (Ockenden et al., 2001). 

Booij, K. and van Drooge, B.L. 2001, Polychlorinated biphenyls andhexachlorobenzene in atmosphere, sea-surface microlayer, and water measured widi semi-permeable membrane devices (SPMDs). Chemosphere 44 91—98. 

Gustavson, K.E. and Haikin, J.M. 2000 Comparison of sampling techniques and evaluation of semipermeable membrane devices (SPMDs) for monitoring polynuclear aromatic hydrocarbons (PAHs) in groundwater. Environ Sci. Technol. 34 4445 451. 

Huckins, J.N. Petty, J.D. Orazio, C.E. Zajicek, J.L. Gibson, V.L. Clark, R.C. Echols, K.R. 1994, Semipermeable Membrane Device (SPMD) Sampling Rates for Trace Organic Contaminants in Air and Water. Abstract of the 15 th Annual meeting of Society of Ertvironmental Toxicology and Chemistry Denver, CO. Abstract MBOl. 

Lohman, R. Corrigan, B.P. Howsam, M. Jones, K.C. Ockenden, W.A. 2001, Further developments in the use of semipermeable membrane devices (SPMDs) as passive air samplers for persistent organic pollutants Field application in a spatial survey of PCDD/Fs and PAHs. Environ. Sci. 

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