FAAS Determination of Lead(Ⅱ) in Sea Water with FI-Pre-enrichment on Micro-column

Trace amount of lead(Ⅱ) in sea water was pre-enriched on a micro-column packed with D412 chelate resin in a FI-system. Twenty mL of sea water sample was injected into the micro-column by wriggling pump at a rate of 3 mL·min-1, and Pb(Ⅱ) in the sample solution was adsorbed on the chelate resin. The micro-column was washed with 5 mL of 0.2 mol·L-1 NH4OAc solution to remove residual seawater. Pb(Ⅱ) was stripped from the micro-column with 4 mL of 4 mol·L-1 HNO3 solution at the rate of 7 mL·min-1. The eluate was transferred directly to the atomizer of the instrument. Peak-shaped absorption signal was recorded and the value of peak height was taken as parameter for quantification. By the enrichment procedure mentioned above, sensitivity for determination of the Pb(Ⅱ) was raised 35 times as compared with the procedure without pre-enrichment. Detection limit (3s) of the method was 1.3 μg·L-1. Test for recovery was made by standard addition method, giving value of recovery of 94.5% with RSD (n=6) of 2.2%.