A greener, rapid and accurate microwave-assisted hydrogen peroxide digestion method for ICP-OES determination of heavy metals in pet food samples

• Published in: Journal of food composition and analysis Vol. 131; p. 106201
• Main Authors: Ncube, Nomatter, Tancu, Yolanda, Mketo, Nomvano
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.07.2024
• Subjects: Heavy metal ions; ICP-OES; Microwave assisted hydrogen peroxide digestion; Multivariate optimization, standard limits; Pet food; Heavy metal ions; Multivariate optimization, standard limits; ICP-OES; Pet food; Microwave assisted hydrogen peroxide digestion
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2024.106201

Microwave-assisted hydrogen peroxide digestion (MW-AHPD) method for determination of Cd, As, Pb, Sn, and Cr in South African pet food samples by inductively coupled plasma-optical emission spectroscopic (ICP-OES) is reported. Multivariate tools and wheat flour certified reference material (FAP80467) assessed limiting factors and reproducibility of the methods respectively. The resulted optimum conditions were: 200 °C, 40 mins, 0.5 g, and 5 mol/L for temperature, time, sample mass and H2O2 concentration, respectively. The method demonstrated excellent accuracy (96–98%), reproducibility (≤ 2.1%) and high detection limits (0.0675–0.3765 µg/g). Then, real pet food samples made from maize, rice, vegetables, fish, and wheat were digested and concentration levels of Cd, Pb, As, Cr and Sn ranged between 11.2 and 22.6, 6.4–11.9, 3.44–13.4, 0.44–2.98 and 0.18–0.98 µg/g, respectively. The three metal ions were above the minimum tolerable limits (Cd: 10 µg/g, Pb:10 µg/g, As: 12.5 µg/g) for some of the fish and wheat based pet food according to the South African regulatory standard. Furthermore, using the AGREEPrep metric tool the method was assessed and had a score of 0.76, confirming its greenness. These findings present MW-AHPD method as an alternative for determination of heavy metals in pet food by ICP-OES. •A dilute H2O2 was used for microwave digestion of pet food.•Rapid multivariate optimization tools generated optimal conditions affecting digestion.•The method was accurate (96–98%) and precise (≤ 2.1%).•Three metals (Cd, Pb and As) were observed to be above tolerable limits of the standard bodies.•The AGREEPrep tool confirmed the greenness of the method with a score of 0.76.