Elemental analysis of flour-based ready-oven foods by slurry sampling inductively coupled plasma optical emission spectrometry

A slurry sampling technique has been utilised for the determination of Na, K, Ca, Mg, S, P, Fe, Mn, Cu and Zn in wheat-flour and flour-based ready-oven foods using ICP-OES and a direct aqueous calibration technique. For 0.1% w/v suspension of flour in 0.1% w/v Triton X-100 and 6% v/v HNO3, the procedural limits of detection (all in mg kg(-1)) for Na, K, Mg, Ca, P, S, Fe, Zn, Mn and Cu were 7.51, 61.1, 0.645, 1.59, 5.25, 4.58, 1.50, 1.07, 0.867 and 1.58, respectively. The precision was expressed as the relative standard deviation (RSD) of 5-10% (n = 10) for 0.1% w/v suspension of wheat-flour. The accuracy was confirmed by the analysis of reference materials wheat-flour GBW 08503 and rice flour NIST 1568a. The proposed method was applied to the analysis of two commercial samples of wheat-flour and four samples of flour-based ready-oven mixtures. The results have shown no significant differences when compared with those obtained after complete digestion of the samples analysed. (c) 2007 Elsevier Ltd. All rights reserved.