Solid phase biosorption, preconcentration and determination of lead in infant fruit juices using an eco-friendly biohybrid material

PAMELA Y. QUINTAS; ELIZABETH AGOSTINI; ANA WEVAR OLLER; LETICIA B. ESCUDERO

Mendoza

Simposio; 15th Rio Symposium on Atomic Spectrometry; 2019

Universidad Nacional de Cuyo

Infants are especially vulnerable to toxic elements that may be present in the food. For this reason, the legislations establishes a maximum residue level (MRL) of toxic elements in food or formulated for infants markedly lower than the MRL allowed in foods for adults. Because of the concentrations of toxic metals found in infant food are generally very low (traces or ultratraces), very sensitive instrumental analytical techniques for their detection are required. However, even with techniques as ETAAS or ICP-MS, the determination may not be feasible for many elements. In these cases, the preconcentration is a very effective tool to increase the sensitivity of analytical methods. Solid-phase extraction (SPE) technique offers advantages such as simplicity, high preconcentration factor, low consumption of organic solvents and other reagents. In this context, the use of biodegradable sorbents as alternatives to traditional SPE sorbents is very welcome. The aim of this work was to use an entirely biodegradable hybrid material to study its dynamic biosorptive potential in a SPE for Pb preconcentration. Initially, Pb(II) was introduced into a flow injection on-line system to quantitative retain the analyte in a micro-column packed with a bacteria (Rodococcus Erytropolis AW3) - hairy root (Brassica napus) hybrid material. The retained analyte was then eluted with a flow of an acid agent and finally determined by electrothermal absorption atomic spectrometry (ETAAS). A retention of 100% was achieved for Pb(II) when the procedure was developed under optimal experimental conditions, such as 100 mg of biosorbent mass, pH 4, 1 ml min-1 of loading rate. The dynamic capacity of the hybrid biosorbent was 36 mg g-1, which favored the reuse of the column during several biosorption-elution cycles. The limit of detection for preconcentration of 5 mL of sample was 5.0 ng L-1 Hg, while the relative standard deviation (RSD) was 4.8% (at 1 µg L−1 Pb and n=10). To the best of our knowledge, this works reports the first use of the biohybrid material in a SPE implemented in a flow injection on-line system for the determination of Pb(II) in infant fruit juices.