176 
Biota samples 
No blank problems were observed with biota samples and the work-up procedure. 
Table 68: Blank values in biota samples 
Trifluralin 
Chlorpyrifos 
-methyl 
Chlorpyrifos 
-ethyl 
Endosulfan I 
Endosulfan 
II 
Blank value of the 
system 3 
<LOD 
<LOD 
<LOD 
<LOD 
<LOD 
Internal Standard b 
(1.3 pg/kg dw 
Fish liver matrix) 
<LOD 
<LOD 
<LOD 
<LOD 
<LOD 
a : Average of 2 measurements containing blank values from solvents, rotary evaporator, 
columns (GPC, aluminium oxide, silica gel), filtration unit; b : Average of 3 measurements 
6.3.3.3 Recoveries 
Water samples 
Table 69 shows the relative recoveries of the analytes (average 5 spike experiments with 
a concentration of 4 ng/L) in sea water samples. At a range of 72 to 120 %, they may be 
considered good. 
Table 69: Relative recoveries of the analytes in sea water samples 
Analyte 
Recovery [%] 
Chlorpyrifos-ethyl 
85 
Chlorpyrifos-methyl 
90 
Endosulfan I 
85 
Endosulfan II 
90 
Trifluralin 
72 
Dicofol 
PCP 
105 
TCPy 
120 
In Table 70. the absolute recoveries of the analytes during sample work-up are 
summarised for the sea water analysis. As expected, no significant losses are observed.