title: Part two: Analytical optimisation of a procedure for lead detection in milk by means of bismuth-modified screen-printed electrodes.
abstract: This work reports the optimisation of a new analytical method for lead ion detection in milk; the electrochemical detection scheme is based on the method that was described in Part I. It features the use of a disposable, environmentally friendly bismuth film electrode to replace the traditionally used (toxic) mercury one while here we report an arduous development of sample treatment so that the simple device can be applied as a screening tool in many settings. For this purpose, a milk pre-treatment procedure by means of wet digestion with HCl, HClO(4), and H(2)O(2) combined with an ultrasonic treatment was developed. The detection of lead ions in treated milk was then carried out using a disposable screen-printed electrode modified with Nafion(®) and an "in situ" bismuth film, with the analysis being performed in anodic stripping voltammetry mode. The analytical method developed allows the detection of milk contaminated with lead ions at a concentration of 20 μg Kg(-1) (legal limit) and it can be proposed as a screening method for routine analysis of lead ions in milk with the advantage of employing inexpensive and portable instrumentation. Moreover, dedicated software supported by a portable instrument introduces procedures that are essential to avoid distortion from ambient lead contamination and also makes it possible for an unskilled operator to carry out each step of the analysis.
authors: Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy.
authors: Josefina
authors: J
authors: Calvo Quintana
authors: Fabiana
authors: F
authors: Arduini
authors: Aziz
authors: A
authors: Amine
authors: Kees
authors: K
authors: van Velzen
authors: Giuseppe
authors: G
authors: Palleschi
authors: Danila
authors: D
authors: Moscone
mesh_terms: D000818:Animals; D001729:Bismuth / Q000737:chemistry*; D002417:Cattle; D055664:Electrochemical Techniques; D004566:Electrodes; D005465:Fluorocarbon Polymers / Q000737:chemistry; D006851:Hydrochloric Acid / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D007854:Lead / Q000032:analysis*; D018625:Microscopy, Atomic Force; D008892:Milk / Q000737:chemistry*; D010472:Perchlorates / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software
chemical_list: D005465:Fluorocarbon Polymers; D010472:Perchlorates; D007854:Lead; C040402:perfluorosulfonic acid; D006861:Hydrogen Peroxide; D006851:Hydrochloric Acid; D001729:Bismuth