180 
Table 77: Limits of quantification (LOQ=threefold LOD) /detection (LOD=threefold peak-to-peak noise) 
of the analytes [pg/kg lipid] in fish liver samples. 
Analyte 
LOQ [pg/kg lw] 
Lima limando 
LOQ [pg/kg lw] 
Gadua morhua 
LOQ [pg/kg lw] 
Platichtys flesus 
Chlorpyrifos-ethyl 
0.6 
3.4 
0.6 
Chlorpyrifos-methyl 
3.6 
3.0 
0.6 
Endosulfan I 
0.4 
4.8 
2.1 
Endosulfan II 
1.1 
6.9 
1.1 
Trifluralin 
0.1 
2.1 
0.6 
6.3.3.5 Laboratory Performance Study 
In 2004, the PCP method involving HPLC-MS analysis was checked through 
participation in a QUASIMEME laboratory performance study for PCP in sea water. 
The result showed excellent agreement with the assigned value (Z score: -0.42), which 
underlines the accuracy of the method developed. 
6.4 Results and Discussion 
6.4.1 Chlorpyrifos 
The analytical method that has been developed and validated (6.3.3) is characterised by 
its high sensitivity, a prerequisite to the determination of pollutants in marine matrices. 
Table 78 summarises the LODs and LOQs achieved in the different matrices. The 
values obtained are on the order of the concentrations of classical pollutants like HCH, 
PCBs, DDT-metabolites or PAH which are presently observed in the open marine 
environment. 
Table 78: Limits of detection (LOD) at a signal-to-noise ratio (S/N) of 3:1 and limits of quantification 
(LOQ, S/N 9:1) for Chlorpyrifos 
LOD 
LOQ 
Sample amount 
Water 
Chlorpyrifos-ethyl 
3 Pg/L 
10 pg/L 
10 L 
Chlorpyrifos-methyl 
3 Pg/L 
10 pg/L 
10 L