220
Permeable Reactive Barrier
LC–MS/MS used for some samples from reactive barriers can be found elsewhere [24–26].
11.2.2.1 GC–MS Analysis
Samples were dissolved in toluene or toluene/acetonitrile mixtures and analyzed using the following conditions: column OPTIMA 5 MS (Macherey Nagel),
30 m × 0.25 mm ID, 0.25 μm film; splitless injection with an injection volume
of 0.5 μL; carrier gas helium with a flow of 1 mL/min; temperature program:
50°C for 3 min → 90°C, 20°C/min for 3 min → 150°C, 4°C/min → 300°C,
8°C/min for 10 min; and single ion monitoring (SIM)-mode detection.
11.2.2.2 LC–MS/MS Analysis
LC–MS/MS analysis was performed with the following conditions: columnNucleodur C18 PAH, 125 × 3 mm ID, 3 μm particle size (Macherey Nagel);
injection volume: 5 μL; flow 0.4 mL/min; binary eluent (A) acetonitrile (B)
1 mM NH 4 OOCCH 3 in water (pH 7), starting with 90% B, decrease to 20% B
within 12 min, hold for 2 min, increase to 90% B within 0.1 min and hold for
5.9 min; temperature 40°C; postcolumn derivatization with 10 μL/min formic acid in water (1%); and detection by MS/MS (electrospray ionization,
multiple reaction monitoring (MRM) mode).
11.2.2.3 Liquid–Liquid Extraction for High Concentrations: GC–MS Only
A sample volume of 20 mL was fortified with a 50 μL internal standard in a
crimp-neck vial. After shaking the sample to dissolve the internal standard,
a triple-distilled pentanoic acid methyl ester (950 μL) was added. After shaking the airtight crimped vial for 60 min in a head-over-head shaker, the sample was centrifuged to facilitate phase separation. An aliquot of 600 μL of the
organic phase was dried over sodium sulfate; 500 μL was used as a retained
sample (stored at –20°C); and 100 μL was used for analysis (in 200 μL amberglass micro vials).
11.2.3 Activated Carbons
Many different types of activated carbons are commercially available and activated carbons from three suppliers were used: “Epibon Y12×40,” “Hydraffin
30N,” “Hydraffin NA15” and “Hydraffin regenerated” from Donau Carbon,
“ROW supra” and “GAC 1240” from Norit, and “F200” and “F400” from
Chemviron. Properties of all activated carbons are available from the supplier. Comparable ACs were used in both of the reactive barriers being studied (see below). However, most experiments in the laboratory (isotherms for
single compounds, column runs) were performed with the AC Epibon Y12×40
(Donau Carbon), whereas a comparison of different activated carbons was
Permeable Reactive Barrier
LC–MS/MS used for some samples from reactive barriers can be found elsewhere [24–26].
11.2.2.1 GC–MS Analysis
Samples were dissolved in toluene or toluene/acetonitrile mixtures and analyzed using the following conditions: column OPTIMA 5 MS (Macherey Nagel),
30 m × 0.25 mm ID, 0.25 μm film; splitless injection with an injection volume
of 0.5 μL; carrier gas helium with a flow of 1 mL/min; temperature program:
50°C for 3 min → 90°C, 20°C/min for 3 min → 150°C, 4°C/min → 300°C,
8°C/min for 10 min; and single ion monitoring (SIM)-mode detection.
11.2.2.2 LC–MS/MS Analysis
LC–MS/MS analysis was performed with the following conditions: columnNucleodur C18 PAH, 125 × 3 mm ID, 3 μm particle size (Macherey Nagel);
injection volume: 5 μL; flow 0.4 mL/min; binary eluent (A) acetonitrile (B)
1 mM NH 4 OOCCH 3 in water (pH 7), starting with 90% B, decrease to 20% B
within 12 min, hold for 2 min, increase to 90% B within 0.1 min and hold for
5.9 min; temperature 40°C; postcolumn derivatization with 10 μL/min formic acid in water (1%); and detection by MS/MS (electrospray ionization,
multiple reaction monitoring (MRM) mode).
11.2.2.3 Liquid–Liquid Extraction for High Concentrations: GC–MS Only
A sample volume of 20 mL was fortified with a 50 μL internal standard in a
crimp-neck vial. After shaking the sample to dissolve the internal standard,
a triple-distilled pentanoic acid methyl ester (950 μL) was added. After shaking the airtight crimped vial for 60 min in a head-over-head shaker, the sample was centrifuged to facilitate phase separation. An aliquot of 600 μL of the
organic phase was dried over sodium sulfate; 500 μL was used as a retained
sample (stored at –20°C); and 100 μL was used for analysis (in 200 μL amberglass micro vials).
11.2.3 Activated Carbons
Many different types of activated carbons are commercially available and activated carbons from three suppliers were used: “Epibon Y12×40,” “Hydraffin
30N,” “Hydraffin NA15” and “Hydraffin regenerated” from Donau Carbon,
“ROW supra” and “GAC 1240” from Norit, and “F200” and “F400” from
Chemviron. Properties of all activated carbons are available from the supplier. Comparable ACs were used in both of the reactive barriers being studied (see below). However, most experiments in the laboratory (isotherms for
single compounds, column runs) were performed with the AC Epibon Y12×40
(Donau Carbon), whereas a comparison of different activated carbons was