Organic micropollutants in Rhine and Meuse a - Riwa

3 METHODOLOGY
3.1 HPLCIUV analysis
Samples are filtered in a 0.45 /lm filter, after which a 15 ml sample is passed over an
adsorption column with the aid of an autosampler (2 mm in diameter x 10 mm long)
packed with PLRP-s adsorbent. This PLRP column is coupled on-line with the HPLC
instrument. After charging, the PLRP column is flushed with 1 ml water containing
5% acetonitrile. Then the PLRP column is connected to the eluent stream from the
HPLC, with the adsorbed material being desorbed in a counterflow process and
subsequently separated in the analytical C-18 column. Detection is performed with a
diode array detector (DAD), which not only measures the UV absorption signal at a
reference wavelength of 215 nm but also records the entire UV absorption spectrum
between 200 and 300 nm.
The arrangement used is shown schematically in Figure 2.
Figure 2
Schematic representation ofthe measuring arrangementfor the
HPLC/UVfingerprint
3.2 Water samples from the Rhine and Meuse
Every month from March 1997 until February 1998, samples from the Rhine at Lobith
and the Meuse at Eijsden were submitted to the Kiwa laboratory by RIWA, and then
analysed within a few days. The data from the samples are given in Appendix 1.
When the results were being processed, the November sample from the Rhine was
seen not to be reliable; it was subsequently disregarded.
The logistics, visual assessment and other results were unremarkable in terms of
samples, preprocessing and analysis.
RllIN'A 11