179 
6.3.3.4 Limits of quantification 
Table 75 to Table 77 show the limits of quantification (LOQ) of the analytes in the 
different matrices. LOQ are calculated for a signal-to-noise ratio (S/N) of 9; the limits 
of detection (LOD) are calculated for an S/N ratio of 3. 
Table 75: Limits of quantification of the analytes [pg/L] in sea water samples 
Analyte 
Limit of Quantification [pg/L] 
Chlorpyrifos-ethyl 
10 
Chlorpyrifos-methyl 
10 
Endosulfan I 
20 
Endosulfan II 
20 
Trifluralin 
7 
Dicofol 
1000 
PCP 
200 
TCPy 
400 
As shown in Table 76, the LOQs for sediments were improved during the project by 
increasing the amount of sediment sample and increasing the polarity of the extraction 
solvent. In this way, different samples may have partly different LOQs. 
Table 76: Comparison of LOQs of the analytes [ng/g dw] in sediment samples for different sample 
amounts (20 and 40 g of sediment) and different solvents (Solvent: A: acetone/hexane 50/50; B; acetone/ 
hexane 75/25. MAE; 10 min, 100°C, 700 W) 
Analyte 
LOQ (20 g sediment) 
[ng/g] A a 
LOQ (40 g sediment) 
[ng/g] A b 
LOQ (40 g sediment) 
[ng/g] B c 
Trifluralin 
0.005 
0.003 
0.0006 
Chlorpyrifos- 
methyl 
0.034 
0.025 
0.023 
Chlorpyrifos- 
ethyl 
0.017 
0.009 
0.007 
Endosulfan I 
0.024 
0.010 
0.011 
Endosulfan II 
0.061 
0.030 
0.014 
a GA371, GA387, GA402 and GA405; b GA419; C GA421. 
The LOQs for biota vary depending on the particular fish species (Table 77) and are due 
primarily to different amounts of lipid and matrix background levels in the three fish 
species studied.