posted by bun .
Species of arsenic found in kriking water include (AsO3)3-, (CH3)2(AsO2)2-, (CH3)AsO3 2-, and (AsO4)3-. Pure water containing no arsenic was spiked with 0.40microgram arsenate/L. Seven replicate determinations gave 0.39, 0.40, 0.38, 0.41, 0.36, 0.35 and 0.39 mcrogram /L.
Find the mean percent recovery of the spike and the concentration detection limit(microgram /L)