Fig. 1. Scheme of the sample pretreatment.

Fig. 2. Chromatograms of the second (5-mL) extract fraction obtained by elution of MSPD columns with aqueous NaH₂PO₄ (0.005 M). Tomato fruit samples (0.5 g) blended with NH₂-silica (1 g) were packed in cartridges and extracted with 4 × 5-mL volumes of eluent. Extracts without cleanup were derivatized with FMOC-Cl prior to HPLC analysis with fluorescence detection. Other chromatographic conditions in the text. (A) Sample fortified at 10 μg/g of glyphosate. (B) Non-fortified sample. Arrows indicate the retention time of glyphosate (GLY).

Fig. 3. Chromatograms of the first (5-mL) extract fraction obtained by elution of MSPD columns with deionized water. Extraction with 2 × 5-mL + 2 × 10-mL volumes of eluent. Extracts analyzed after cleanup on SAX-OH and derivatization with FMOC-Cl. Other conditions in Fig. 2. (A) Sample fortified at 40 μg/g of AMPA. (B) Non-fortified sample. Arrows indicate the retention time of AMPA.

Fig. 4. Chromatogram of a fortified tomato sample (1 μg/g of glyphosate).

Fig. 5. Chromatogram of a fortified tomato sample (1 μg/g of AMPA).

Recoveries of glyphosate in four elution fractions (5 mL each) from MSPD columns prepared with tomato fruit samples additioned with different volumes of 1 M HNO₃ solution (sample spiked at 10 μg/g of glyphosate; eluent: NaH₂PO₄ 0.005 M)

Recoveries of AMPA in different elution fractions from MSPD columns using deionized water as eluent (sample spiked at 40 μg/g of AMPA)

Overall percent recoveries and RSD for pesticides in fortified tomato fruit using the whole procedure illustrated in Fig. 1