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 × 11 cm length) situated in a switching valve for the FI set up. A single standard calibration could be obtained by plotting the loaded µg Pb2+ vs. FI response (absorbances). The loaded µg Pb2+ is calculated: μg Pb2+ = FRload × LT × 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 (µg mL-1). A linear calibration equation was obtained: FI response (absorbances) = 0.0018 [µg Pb2+] + 0.0032, R2 = 0.9927 for 1-150 µg Pb2+, and RSD of less than 20% was also obtained. Application of the developed procedure has been demonstrated in real samples.
Keywords: FlameAAS; alginate-polyurethane composite; flow injection; in-valve column; lead(II); monolithic column.