Microwave induced plasma optical emission spectrometry for multielement determination in instant soups

Abstract

This paper presents the use of microwave induced plasma optical emission spectrometry (MIP OES) for food analysis. A method for determination of Cu, K, Mg, Mn, P, and Zn in instant soups by MIP OES with N2 plasma was developed. Sample preparation procedure consisted of microwave-assisted digestion with dilute nitric acid solution. Accuracy was evaluated based on the analysis of three certified reference materials: NIST 1515 (apple leaves), NIST 1568b (rice flour) and NIST 3234 (soy flour). Recoveries ranged from 83.3–107.5 % for target elements in these materials. Addition and recovery experiments were performed and recoveries ranged from 86.0–106.0 %. All determinations were performed using external calibration. Limits of detection for Cu, K, Mg, Mn, P, and Zn were 0.09, 4.9, 1.0, 0.04, 5.4 and 0.88 mg kg-1, respectively. Concentrations ranges of Cu, K, Mg, Mn, P and Zn in various types of instant soups samples were found between 1.31–13.8, 1135 - 17.824, 172–567, 1.72–12.1, 608 - 1826 and 2.90–12.1 mg kg-1, respectively. The use of N2 microwave-induced plasma is demonstrated as a low cost alternative for routine analysis.