Environmental Engineering Reference
In-Depth Information
1
Introduction
Extensive survey data for antifouling compounds have been reported for ma-
rine coastal, docks and harbour waters [1-4]. In addition, the environmental
impact on the aquatic environment and fate of organotin compounds, in
particular tributyltin (TBT) and copper is well documented [3-7]. As an al-
ternative to organotin compounds, the use of which is now regulated and
limited to vessels greater than 25 m in length, organic booster biocides were
introduced. However, the potential of booster biocides to cause pollution
has also been of concern for several research studies carried out during the
last few years [8-11]. Maximum concentration levels found up to approx.
1700 ng L
-1
have been reported in areas of high boating activity or enclosed
marinas [9, 12-14], while in marinas with higher water exchange rates, lower
concentration levels have been encountered (low ng L
-1
) [15-17]. However,
those concentrations can be sufficiently relevant to pose a risk to aquatic life.
Because of the potentially dangerous consequences of the presence of
booster biocides in the environment, several analytical methodologies
have been described in the literature. Most of the methods involve a pre-
concentration step, a clean-up of the extracts and a chromatographic separa-
tion by gas and liquid chromatography.
In general, because of their low concentration levels, trace-level aqueous
samples have to be extracted and enriched prior to their analytical determin-
ation. Several methods have been developed to extract aqueous samples con-
taining antifouling compounds. Liquid-liquid extraction (LLE) [10, 18] and
solid-phase extraction (SPE) [10, 11, 19, 20] were the dominant approaches
for sample preparation. Among these, the LLE method has well-known op-
erating disadvantages (e.g. time-consuming and requires large amounts of
organic solvents). In the past few years, the application of new techniques
reflects the current analytical trends (reduction of organic solvents, automa-
tion of the sample preparation step). In addition to the common use of
SPE, examples of current techniques applied are solid-phase microextrac-
tion (SPME), which is a simple procedure, inexpensive, efficient and no
solvent for sample preparation is necessary, [21, 22] as well as solvent mi-
croextraction (SME) [23] and headspace solid-phase microextraction (HS-
SPME) [24] for the analysis of booster biocides. Similar goals have led to
the application of new extraction techniques for sediment samples, includ-
ing microwave-assisted extraction (MAE) [25], supercritical fluid extraction
(SFE), or SPME [26], as an alternative to traditional extraction methods such
as ultrasonication.
Although FTD or ECD selective detection systems have been included
in the development of analytical methods [21, 23], the reported methodol-
ogy in the literature for booster biocides have been to a great extent based
on the application of gas chromatography-mass spectrometry (GC-MS) sys-
