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Values reported are means (n = 3).

aPreviously reported by Alvarez et al. [23].

bRs was determined under turbulent conditions only.

Values reported are means (n = 3).

aPreviously reported by Alvarez et al. [23].

bRs was determined under turbulent conditions only.

8.4 STUDY CONSIDERATIONS 8.4.1 Use and processing

Figure 8.4 shows the general processing, enrichment, and fractionation scheme for POCIS samples. For transport to and from the laboratory and during sample storage, POCIS is stored frozen in solvent-rinsed airtight container, such as a metal paint can. At the onset of processing, the exterior of POCIS membranes is gently cleaned with a soft brush and running water to reduce the probability of contamination of sor-bents with particulate matter. Care must be taken during this cleaning process not to damage the membrane. Then, the POCIS membranes are separated and the sorbent is transferred with a suitable solvent such as methanol into a glass, gravity-flow chromatography column plugged with glass wool. The sequestered chemicals are recovered from the sorbent using an optimized solvent elution scheme. The solution containing the targeted analytes is then reduced in volume by rotary evaporation, solvent reduction with a N2 stream, or similar methods. Depending on the requirements of the analytical method, the sample may undergo further enrichment and fractionation. Afterwards, the

Exterior Cleani g

Solvent Extraction & Chemical Recovery

Transport to lab sealed in airtight can

Transport to lab sealed in airtight can

Enrichment and Fractionation

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