Determination of Lead Employing Simple Flow Injection AAS with Monolithic Alginate-Polyurethane Composite Packed
In-Valve Column

A simple flow injection FlameAAS for lead determination with an alginate-polyurethane
composite (ALG-PUC) monolithic in-valve column has been developed. The ALG-PUC monolithic
rod was prepared by mixing methylene diphenyl diisocyanate with polyol and sodium
alginate with the ratio of 2:1:1 by weight for a 5 min polymerization reaction. It was then put
into a column (0.8 cm i.d x 11 cm length) situated in a switching valve for the FI set up. A single
standard calibration could be obtained by plotting the loaded ug Pb²⁺ vs. FI response (absorbances).
The loaded ug Pb²⁺ is calculated: ug Pb²⁺ = FR_load x LT x CPb²⁺, where the FR load is the flow rate of the loading analyte solution (mL min􀀀1), LT is the loading time (min), and CPb²⁺ is the Pb²⁺ concentration (ug mL^-1). A linear calibration equation was obtained: FI response (absorbances) = 0.0018 [g Pb2+] + 0.0032, R2 = 0.9927 for 1–150 ug Pb²⁺, and RSD of less than 20% was also obtained. Application of the developed procedure has been demonstrated in real samples.