The latter term was measured giving k /k. = 11.0 + 0.4. It 
follows that a i — 
In order to calculate the weight fraction f of analyte in 
the sediment sample, the following relationship a was used: 
f 
a 
. jig of a 
g sediment' 
of a 
CH 2 C1 2 
) 
V e (ml CH 2 C1 2 ) 
W (g sediment) 
o 
This uses the volume of the final concentrate extract, and 
the initial weight W g of dry sediment to provide the weight of 
DBP or DEHP. The units, pg/g, are the same as parts per million 
(ppm). 
RESULTS AND DISCUSSION 
Preliminary Results with HPLC 
A detailed study (Gingras 1979) was made of the basis for 
applying modern liquid chromatography to analysis of field 
sediment and water samples for alkyl phthalates. Previously, 
Heilman (1978) had developed the use of adsorption liquid chro¬ 
matography but this is prone to irreversible adsorption effects 
and lesser reproducibility. Amundson (1978) used reversed phase 
LC with Bondapak C-18 as the stationary phase with methanol plus 
1 percent acetic acid as the carrier. More sharply defined 
peaks were obtained more rapidly with tetrahydrofuran-water 
mixtures, 60:40 linear programmed in a 5-minute period to 90:10 
at 2.0 cm^/ml flow rate. 
Analysis was made by LC bases on preliminary test samples of 
phthalates as manufactured, named and provided to us by Tenneco. 
These are shown in Figures 8-12. The LC technique has notable 
stability but qualitative identifications can only be shown to 
be consistent or inconsistent with the LC retention volumes. The 
time of analysis was only 7 minutes, or less than half required 
by Anumdson. The resolution of a synthetic mixture of the three 
reference materials DOP, DIDP (diieodecylphthalte) and DTDP is 
illustrated in Figure 9. Later on in the study we established 
that Tenneco's "DOP" was actually DEHP. 
Analysis of Tenneco Pond water was carried out using the Sep 
Pak technique and the results are shown in Figure 10. The pre¬ 
sence of DOP 0.25 + 0.15 ppm and DTDP (ditridecylphthalate, 
1.5 + 0.2 ppm) were estimated by LC alone. The presence of 
phthalate esters in downstream water samples could not be de 
tected by LC so these will not be reported here. The first peak 
56 
