Solid Phase Extraction of Lead Using Eggshell Membrane in Water Samples Prior to Graphite Furnace Atomic Absorption Spectrometric Determination

A chicken eggshell membrane (ESM) is composed of many protein fibers, and available in large quantities as a by-product of the food industry. According to a study by Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR) Spectrometry, the ESM with an intricate lattice network of stable and water-insoluble fibers, and special functional groups such as hydroxyl (—OH), carboxyl (—COOH), aminol (—NH₂), showed an excellent potential for adsorption and exchange of metal ions. In this paper, the ESM was applied to separate and enrich Pb(Ⅱ) from a water sample under a pH of 6. The trace lead eluted by 5 mL 3% HNO₃ was determined by using Graphite Furnace Atomic Absorption Spectrometry (GFAAS). Important parameters, such as the sample pH, sample flow rate, concentration and volume of eluent, and interference of coexisting ions were comprehensively studied and optimized. Under the optimized conditions, an enrichment factor of 30 was obtained. The method detection limit for lead was 0.017 ng/mL (3σ) and the relative standard deviation (RSD, n=11) was 3.45%. The recoveries of lead in the spiked environmental water samples ranged from 96.0% to 104.2%. The proposed method was applied to the determination of trace lead in environmental and drinking water samples with satisfactory results, which demonstrates that the ESM method can be a simple, low-cost, environmentally-friendly SPE adsorbent for lead pretreatment and enrichment from real water samples.