A. Aminot et R. Kerouel, An automated photo-oxidation method for the determination of dissolved organic phosphorus in marine and fresh water, MAR CHEM, 76(1-2), 2001, pp. 113-126
A segmented flow automated method with on-line photo-oxidation for the dete
rmination of dissolved organic phosphorus + soluble reactive phosphorus (DO
P + SRP) in seawater and fresh water is described here. A low-power lamp wa
s used for a compact, easy-to-handle and low-ozone-producing manifold. The
influence of seawater matrix components was studied in detail using natural
seawater and salt solutions spiked with DOP model compounds. Bromide was f
ound to be the most inhibitory species in seawater. The work shows that mos
t salt solutions referred to as artificial seawater are not satisfactory mo
del matrices to test the actual seawater matrix effect. Since DOP recovered
in undiluted seawater samples was about half that obtained in fresh water
samples, the described method includes a 5- to 6-fold dilution of seawater
samples. This simple procedure overcomes matrix effects and provides satisf
actory DOP recovery. No pH effect was found in the 6-9 range corresponding
to most natural waters. The standard deviation was 0.007 mu mol l(-1) and t
he limit of detection 0.02 mu mol l(-1). Linearity was tested up to 5 mu mo
l l(-1) of DOP, i.e. far above naturally occurring values. A throughput of
20 samples per hour is easily achieved. (C) 2001 Elsevier Science B.V. All
rights reserved.