Validating Analytical Protocols to Determine Selected Pesticides and PCBs Using Routine Samples

Table 3

Study of constant bias by means the analysis of three sediment subsamples of 0.6, 1.6, and 2.6 grams, respectively.

(ng)	Subsample 1	Subsample 2	Subsample 3			()%		()
				-	-	-	-	-	-
o,p′-DDD	44 ± 5.2	102 ± 5.2	160 ± 28	10	−7.5	0.109	0.209	2.2	0.4
p,p′-DDD	45 ± 3.4	99 ± 12	143 ± 8.3	14	−29	0.080	0.195	3.7	1.5
o,p′-DDE	4.3 ± 0.26	11 ± 0.41	17 ± 3.4	0.47	−0.58	0.059	0.231	1.9	0.2
p,p′-DDE	23 ± 2.1	52 ± 1.6	78 ± 11	6.5	−8.9	0.085	0.165	3.3	1.0
HCB	3524 ± 209	8451 ± 198	13832 ± 421	594	154	0.055	0.049	3.1	0.4
α-HCH	2.9 ± 0.06	15 ± 2.6	41 ± 6.0	−4.1	27	0.066	0.319	22	5.9
β-HCH	61 ± 4.6	145 ± 29	261 ± 16	11	40	0.098	0.306	1.8	0.9
γ-HCH	8.2 ± 1.7	18 ± 1.9	40 ± 12	2.5	18	0.190	0.373	5.8	2.7
PCB-28	442 ± 49	997 ± 77	1607 ± 138	112	−23	0.105	0.152	2.4	0.1
PCB-52	143 ± 18	352 ± 25	576 ± 59	19	7.1	0.119	0.158	1.6	0.1
PCB-101	68 ± 5.8	178 ± 16	252 ± 2.8	2.8	−60	0.085	0.135	0.5	2.5
PCB-118	30 ± 5.0	63 ± 4.4	104 ± 5.5	11	1.5	0.154	0.120	2.3	0.2
PCB-138	3.3 ± 0.15	7.7 ± 0.59	13 ± 1.1	0.65	1.4	0.050	0.149	3.9	1.2
PCB-153	10 ± 0.63	22 ± 2.1	40 ± 3.0	3.0	5.2	0.065	0.162	4.5	1.4
PCB-180	14 ± 2.1	25 ± 2.6	38 ± 3.4	7.2	−3.8	0.144	0.186	3.6	0.8