TABLE 3.

Intra‐ and inter‐day precision of the proposed method (RSD, %) for spiked tap water samples.

	Intraday precision (%RSD, $n=18$)			Interday precision (%RSD, $n=30$)
Analyte	Level 1	Level 2	Level 3	Level 1	Level 2	Level 3
Metalaxyl	4.8	6.5	8.5	7.7	7.1	6.3
Benalaxyl	3.2	5.8	5.9	5.2	8.2	4.2
Chlorpyrifos	8.6	7.5	7.5	7.5	7.0	7.1
Endrin	8.4	4.4	7.2	6.9	8.6	8.1
DDT	4.1	6.6	7.4	6.6	7.4	7.1
Bifenthrin	2.8	7.7	7.5	6.5	7.5	5.2

Note: Level 1: 80 µg/L for metalaxyl; and 40 µg/L for benalaxyl, chlorpyrifos, endrin, 4, 4′‐DDT and bifenthrin. Level 2: 200 µg/L for metalaxyl; and 100 µg/L for benalaxyl, chlorpyrifos, endrin, 4, 4′‐DDT and bifenthrin. Level 3: 800 µg/L for metalaxyl; and 400 µg/L benalaxyl, chlorpyrifos, endrin, 4, 4′‐DDT and bifenthrin.