Reports of extraction
of silicone vary widely from single soaking periods, to extended Soxhlet
extraction over 90 h.22 (link),24 (link) To determine an adequate extraction
method, precleaned silicone wristbands were infused with four deuterated
PAHs similar to a previous method.23 (link) Briefly,
acenaphthylene-D8, fluorene-D10, phenanthrene-D10, and pyrene-D10
were pipetted into a 1 L jar filled with approximately 50–100
g of silicone and a methanol/water (1:1, v:v) solution. Compounds
were allowed to equilibrate for three days since the ratio of methanol/water
used was 1:1 rather than 4:1 as originally described.23 (link) Using a 1:1 ratio requires less deuterated compounds in
the infusing solution since more will partition to the silicone. Wristbands
were dried as previously described, and then three rounds of extraction
at two time periods of either 2 or 24 h were used to examine efficiency
(Supporting Information (SI) Figure S1).
Postdeployment cleaning consisted of two rinses with purified water,
and one rinse with isopropyl alcohol to reduce any water residue and
further remove surface particulates (SI Figure S2). Field samplers were extracted twice with 100 mL of ethyl
acetate on an orbital shaker at 60 rotations per minute (VWR) for
nominally 2 h each time. Both rounds of extraction were combined and
reduced to 1 mL (measured with premarked glassware) with closed-cell
evaporators (Biotage LLC, Charlotte, NC). Samples were transferred
and stored in amber chromatography vials at 4 °C.
To examine
whether PAHs would degrade after sorption to the wristband,
or if field/handling conditions would influence exposure concentrations,
we again infused wristbands with several PAHs (fluorene-d10, benzo[b]fluoranthene-d12,
fluorene, pyrene, and benzo[b]fluoranthene) and either exposed outdoors
(in sun or shade) or within PTFE storage bags at approximately −20
°C, 23 and 35 °C. Additional details are described in theSI . Silicone PSDs were extracted and stored as
described above.
of silicone vary widely from single soaking periods, to extended Soxhlet
extraction over 90 h.22 (link),24 (link) To determine an adequate extraction
method, precleaned silicone wristbands were infused with four deuterated
PAHs similar to a previous method.23 (link) Briefly,
acenaphthylene-D8, fluorene-D10, phenanthrene-D10, and pyrene-D10
were pipetted into a 1 L jar filled with approximately 50–100
g of silicone and a methanol/water (1:1, v:v) solution. Compounds
were allowed to equilibrate for three days since the ratio of methanol/water
used was 1:1 rather than 4:1 as originally described.23 (link) Using a 1:1 ratio requires less deuterated compounds in
the infusing solution since more will partition to the silicone. Wristbands
were dried as previously described, and then three rounds of extraction
at two time periods of either 2 or 24 h were used to examine efficiency
(
Postdeployment cleaning consisted of two rinses with purified water,
and one rinse with isopropyl alcohol to reduce any water residue and
further remove surface particulates (
acetate on an orbital shaker at 60 rotations per minute (VWR) for
nominally 2 h each time. Both rounds of extraction were combined and
reduced to 1 mL (measured with premarked glassware) with closed-cell
evaporators (Biotage LLC, Charlotte, NC). Samples were transferred
and stored in amber chromatography vials at 4 °C.
To examine
whether PAHs would degrade after sorption to the wristband,
or if field/handling conditions would influence exposure concentrations,
we again infused wristbands with several PAHs (fluorene-d10, benzo[b]fluoranthene-d12,
fluorene, pyrene, and benzo[b]fluoranthene) and either exposed outdoors
(in sun or shade) or within PTFE storage bags at approximately −20
°C, 23 and 35 °C. Additional details are described in the
described above.
