1.1.1 Chemical and laboratory material and equipments

For dry decomposition there were used: nitric acid (65%, p. p., Lachema Neratovice CZ and Suprapur Merck, Germany), demineralised water (quality degree 1 according to EN ISO 3696 for the calibration of ICP-OES). Water calibration solutions with one element (Analytika, Ltd., CZ) were used for the calibration of F-AAS: Ca (1.000 ± 0.002 g L-1) in 2% HCl, Cu (1.000 ± 0.002 g L-1) in 2% HNO3, Fe (1.000 ± 0.002 g L-1) in 2% HNO3, K (1.000 ± 0.002 g L-1) in 2% HNO3, Mg (1.000 ± 0.002 g L-1) in 2% HCl, Mn (1.000 ± 0.002 g L-1) in 2% HNO3 and Zn (1.000 ± 0.002 g L-1) in 2% HNO3. For the testing of the dry decomposition method, a certified reference material NIST 8436 (Durum Wheat Flour) and internal reference material (IRM) from International Plant Analytical Exchange (IPE), RM Sample 3, Wheat 684, Quarterly Report 2000.3 were used. For the calibration of AAS and testing of the method of modified dry decomposition the following materials were used: calibration solutions with one element (Analytika, Ltd., CZ) 1.000 ± 0.002 g L-1 in 2% HNO3 for elements Cu, Pb and Zn, while cadmium was dissolved in 2% HCl. Muffle oven (LM 112.10, MLW, Germany), heating plate ALTEC JRT 350 with temperature graduation per 10 °C and ultrasonic bath Elma Transonic T660/H were used for the dry decomposition of samples. Analyses of the metals were performed by atomic spectrometer VARIAN SpectrAA 110 (VARIAN A. G., Australia) with the possibility emission spectra and Varian SpectrAA 280Z atomic absorption spectrometer furnished with GTA 120 electrothermic atomizer. Laboratory hammer mills LM3100 and LM120, falling number bath FN 1500, Glutomatic 2200 and Gluten Index centrifuge 2015 made by Perten Instruments AB (Sweden) were used for the determination of Falling number, gluten content and gluten index. For protein determination there were used: nitric acid (HNO3, 65%, p. a., Lachema Neratovice, CZ), automatic nitrogen analyzer Kjeltec system. A laboratory mill LM3100, lactic acid and bromphenol blue were used for the determination of sedimentation index (Zeleny sedimentation test).

1.1.2 Soil analysis

Soil pH was measured in suspension using 1:2.5 (w/v) ratio of soil and 0.2 M KCl at 20 ± 1°C by WTW pH 340i set. Available forms of nutrients (Ca, K, Mg and P) were determined using the Mehlich 3 soil extraction procedure (Mehlich, 1984; Zbiral, 2000) and organic nitrogen by the Kjeldahl method (Bremner, 1960).