Chemical Vapour Deposition of MWCNT on Silica Coated Fe₃O₄ and Use of Response Surface Methodology for Optimizing the Extraction of Organophosphorus Pesticides from Water

Table 3

Determination of OPPs in water sample (nd = not detected and D = detected).

OPPs	Vaal River water				Vaal Dam water
	spiked (μg/L)	Quantified (μg/L)	%R(a)	RSD %	Quantified (μg/L)	%R(a)	RSD %
Azinphos methyl	0	D			D
	10	9.1	90.8	3.8	9.4	93.6	6.5
	50	45.2	90.4	6.2	46.3	92.6	4.9
Chlorpyrifos	0	D			D
	10	8.6	86.0	5.9	9.1	91.5	10.4
	50	46.7	93.5	5.6	46.9	93.8	5.5
Malathion	0	D			D
	10	8.8	88.3	6.3	8.6	86.3	7.5
	50	42.0	84.0	9.6	43.1	86.2	2.9
Parathion	0	nd			D
	10	10.1	101.4	4.8	8.9	88.7	5.9
	50	45.8	91.5	8.2	45.1	90.2	9.8