Analytical parameters of the CPE – spectrophotometric method^a.

Methods	Sample	Linear Equation	R 2	% RSD, n = 3	LOD (μg L−1)	LOQ (μg L−1)
CPE-OFX 0309	1	y = 0.027x + 0.103	0.9974	0.75	0.12	0.40
	2	y = 0.035x + 0.018	0.9986	1.28	0.09	0.31
	3	y = 0.016x + 0.071	0.9982	0.93	0.21	0.69
	4	y = 0.011x + 0.109	0.9974	0.29	0.31	1.03
	5	y = 0.016x + 0.212	0.9993	0.14	0.20	0.67
CPE-DC 193C	1	y = 0.017x + 0.188	0.9927	0.23	0.18	0.61
	2	y = 0.014x + 0.197	0.9942	1.14	0.24	0.81
	3	y = 0.013x + 0.213	0.9982	1.73	0.26	0.85
	4	y = 0.036x + 0.309	0.9946	0.24	0.59	1.95
	5	y = 0.008x + 0.341	0.9985	0.28	0.42	1.40

^a(1) = Tap water; (2) = River water; (3) = Lake water; (4) = Pond water; (5) = Paddy field water.