Chromatographic and spectroscopic determinations of some mycotoxins and metals using novel liquid extraction methods in various food products

In this study, totally five different mycotoxins in several kinds of foodstuffs were determined by chromatographic analysis using three different extraction technologies. Thin-layer chromatography with densitometry and high performance liquid chromatography were used in optimization steps and / or in sample analysis. Besides this, several major and trace elements in wine and beer samples were detected using atomic absorption / emission spectrometer. 5-hydroxymethylfurfural was extracted from five grape vinegar and seven fruit wine samples by liquid-liquid extraction and extracts were directly applied to TLC- scanner with UV detection. The 5-hydroxymethylfurfural in all studied samples was detected and ranged from 0.59 to 33.10 mg per L. The limits of detection and quantification of this method were 0.045 and 0.125 µg per mL, respectively. For robustness, within and between-day repeatability of the method were calculated as percentage of 4.5 and 8.6. For ochratoxin A and zearalenone analysis, a newly dispersive liquid liquid microextraction method was improved and applied to eight red and four white wine samples for ochratoxin A and thirteen beer samples for zearalenone. Under the optimum extraction conditions, the extraction recovery percentage and the enrichment factor were calculated as 63.9 and 34.5 for OTA and 83 and 43.3 for ZEN, respectively. The linearity of the DLLME method was employed in the concentration range of OTA in wines and ZEN in beer from 0.03 to1 ng per mL and from 0.4 to 120 ng per mL, respectively. The recovery of method was in the range of percentage between 63-109 for OTA and 71–108 for ZEN at 0.1 and 0.5 ng per mL, at 10 and 20 ng per mL spiking levels, respectively. For tenuazonic acid and cyclopiazonic acid analysis in tomato juice samples, a novel cloud point extraction method was developed. The extraction recoveries as percentage were found as 39.9 and 94.6 for tenuazonic acid and cyclopiazonic acid, respectively. The linearity of the proposed method was in the concentration range 0.01-2 ng per mL for both mycotoxins. The recovery as percentage of this method was in the range of 84 to 98 for cyclopiazonic acid and 83 to 97 for tenuazonic acid at 0.05 and 0.1 ng per mL spiking levels. In this study, Ca, Mg, Na, K, Fe, Cu, Zn and Pb were also studied in grape wine and beer samples. For this, atomic absorption spectrometer equipped with flame and graphite furnace atomization and, atomic emission spectrometer were used for all wine and beer samples after acid digestion using nitric acid and hydrogen peroxide. The accuracy of the method was confirmed by spiking at two levels to real samples for studied each metal ion.