Masking Agents Evaluation for Lead Determination by Flow Injection-Hydride Generation-Atomic Fluorescence Spectrometry Technique: Effect of KI, L-Cysteine, and 1,10-Phenanthroline

Abstract

Hydride generation (HG) of lead technique presents interferences from foreign ions of complex matrix samples. In order to minimize these interferences, the effect of masking agents such as KI, L-cysteine, and 1,10-phenanthroline was studied in the absence and in the presence of selected interfering species (As, Cr, Cu, and Fe). Different modes of addition of masking agents were accomplished, that is, to either sample or KBH4 reducing solution. The lead determinations were performed using a flow injection analysis (FIA) system coupled to HG and atomic fluorescence spectrometry (AFS). The linearity of calibration curves (1–10 μg Pb L−1) was not affected by the addition of the masking agents. The use of KI in the reducing solution diminished interferences from concentrations of As and Cu, while 1,10-phenanthroline showed a positive effect on the interference by As. Moreover, Cr and Cu appeared to be the most serious interfering ions for plumbane (PbH4), because they drastically reduced the analytical signal of lead. Fe did not present any interference under the employed experimental conditions, even at high levels. The accuracy was established through the analysis of certified reference material (i.e., BCR-610, groundwater) using KI as masking agent. The detection limit reached by FIA-HG-AFS proposed methodology was 0.03 μg Pb L−1.

A Simple Distance Paper-Based Analytical Device for the Screening of Lead in Food Matrices

“…Although KCN is an effective agent to mask and diminish the effect of Cu, it is not recommended for use in food analysis because of its high toxicity. Alternative masking reagents for the Cu should be further investigated such as thiosemicarbazide and its derivatives [ 62 , 63 ] and potassium iodine [ 64 ]. In addition to Cu, other ions such as Al 3+ , Cr 3+ , or Fe 3+ could interfere with the assay as those ions can potentially bind to the CA [ 38 ].…”

Development of distance paper-based devices and electrochemical sensors for food and cosmetic safety assessment

“…Although KCN is an effective agent to mask and diminish the effect of Cu, it is not recommended for use in food analysis because of its high toxicity. Alternative masking reagents for the Cu should be further investigated such as thiosemicarbazide and its derivatives (Ibrahim et al, 2018;Youssef et al, 2012) and potassium iodine (Beltrán et al, 2016). In addition to Cu, other ions such as Al 3+ , Cr 3+ , or Fe 3+ could interfere with the assay as those ions can potentially bind to the CA (Sakamaki et al, 2017).…”