Screening and Quantification of Aflatoxins and Ochratoxin a in Different Cereals Cultivated in Romania Using Thin‐layer Chromatography‐densitometry

Abstract

The main focus of our study was to implement a rapid, inexpensive and reliable method that could be utilized to check the cereals for safety (i.e., screening for total aflatoxins, as well as individual B1, B2, G1, G2 aflatoxins and ochratoxin A). We developed a protocol by which we were able to isolate mycotoxins from cereals collected from different regions of Romania. After extraction in chloroform, the mycotoxins were separated by thin‐layer chromatography (TLC) and quantified using densitometry. Forty‐three samples of different cereals (wheat, maize, rye and Triticale) were analyzed. Twenty‐five of the 43 samples (58.14% of the total number) were found to be contaminated with different mycotoxins in various concentrations: aflatoxin B1 (1.6–5.7 µg/kg), aflatoxin B2 (0.89–4 µg/kg), aflatoxin G1 (1.2–5.76 µg/kg), aflatoxin G2 (0.96–3.4 µg/kg) and/or 4.3–30 µg/kg ochratoxin A. The concentration of total aflatoxin contamination ranged from 11.2 to 10.8 µg/kg. Among the different cereals, the highest number of contaminated samples was found to be in the wheat samples (62.5%). The method outlined in this study has been adopted already by our laboratory for current analyses of mycotoxins. The results obtained using this method is in compliance with the strict regulatory guidelines developed both in Romania, as well as in the European Union. PRACTICAL APPLICATIONS Thin‐layer chromatography (TLC) is a rapid, inexpensive and convenient method that can be used routinely to screen for mycotoxins. This article describes the detailed procedures for the extraction, purification and quantification of aflatoxins and ochratoxin A, using TLC. Using this method one can identify concomitantly five different mycotoxins and by coupling it with densitometry a quantitative determination is also possible. Therefore, this could become a routine technique in regional laboratories responsible for checking agrifood safety.

Surface plasmon resonance biosensor for the detection of ochratoxin A in cereals and beverages

“…In this study, the LODs for OTA in white and red wine were determined to be 0.41 ± 0.043 and 0.33 ± 0.028 ng mL −1 , respectively, with the IC 50 values of 13.2 ± 1.2 and 10.7 ± 0.7 ng mL −1 , respectively. These LOD values were lower than values in previous reports [9,13,31]. Recently, Flajs et al reported lower detection limits (5 ng L −1 ) for OTA in wine using HPLC and modified ELISA but both of the methods used required complex sample clean-up and pre-concentration steps prior to analysis [37].…”

“…Chromatographic methods such as thin-layer chromatography (TLC), gas chromatography (GC) and high-performance liquid chromatography (HPLC) with immunoaffinity columns and fluorescence detection [12][13][14][15][16] provide sensitive and specific techniques, but generally require multiple steps prior to detection. These multiple steps include extraction with organic solvents from complex matrices, extensive sample clean-up, and pre-concentration and sometimes analyte derivatization.…”

Investigation on image processing parameters for plate evaluation in TLC analysis of mycotoxins

“…Moreover, better values for determination coefficient (R 2 ), and method performance parameters (LOD and LOQ) were obtained, compared to published data in scientific literature [24].…”

“…TLC analysis for mycotoxins is still popular for both qualitative and quantitative determinations [17][18][19][20][21][22][23][24]. Silica gel layers seem to be the most common stationary phases used for such investigations.…”

Determination of Ochratoxin A in Selected Cereal Grains Retailed in Nairobi County, Kenya

“…Extraction was done according to guidelines by Braicu, Puia, Bodoki, and Socaciu (2008). To 10 g of sample in 250 mL conical flask, 50 mL of chloroform was added and sonicated for 10 minutes at room temperature.…”