Environmental Engineering Reference
In-Depth Information
9-methylacridine (
S
0
= 9.3 mg/L, determined in this study) is assumed to be
almost independent from environmentally relevant pH-values due to the
low pK
a
= 3.9 [19].
11.2 Experimental
11.2.1 Instrumentation and Materials
Numerous methods were applied to analyze samples of different origins.
In addition to compounds such as the EPA-PAHs and the short-chained
alkylated phenols, alkylated PAHs and NSO-heterocycles usually found in
groundwater were incorporated into the compound list. This list of com-
pounds was verified by analyzing contaminated groundwaters using gas
chromatography-mass spectrometry (GC-MS) (full scan, m/z = 100-500)
and was expanded to account for additional compounds and numerous iso-
mers. A list of compounds analyzed in this study can be found in Table 11.7.
Compounds were purchased from a number of suppliers, typically as ref-
erence standards. In addition to the reference standards, single compounds
with purities between 95% and 99% were used as received. 2-Methylquinoline
was distilled before use.
Concentrations of single compounds and mixtures for the determination
of adsorption isotherms were obtained using high-performance liquid chro-
matography with a diode array detector (HPLC-DAD), HPLC-fluorescence
(Agilent HPLC-type 1100 series), and headspace GC (Perkin Elmer Autosystem
XL, HS40 headspace sampler, and flame ionization detector (FID). Solutions
from column experiments were analyzed by GC-MS (Perkin Elmer Turbo
Mass and Thermo Finnigan Trace DSQ) and samples from field measure-
ments were analyzed following appropriate extraction processes using GC-
MS and liquid chromatography-mass spectrometry (LC-MS/MS) (Agilent
6430 Triple Quadrupol with Agilent HPLC-type 1200 series). In addition to
the analysis for organic compounds, on-site parameters (pH, conductivity,
temperature, oxygen concentration, and redox potential; instrumentation
from WTW, Weilheim, Germany) and the concentrations of anions (ion chro-
matography, Dionex DX 120) and cations (ICP, Perkin Elmer Optima 3300RL)
were obtained for groundwater samples. Cyanide analysis was performed at
the University of Cologne (Germany).
11.2.2 Analytics
Most samples were extracted using liquid-liquid extraction with penta-
noic acid methyl ester [20] and analyzed by GC-MS [20-22] and a very brief
description of this method is given only here. Extraction efficiencies, detec-
tion limits, and more details of this method besides a more sophisticated
solid-phase extraction (SPE) [23] for low concentrations in combination with
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