Rapid and automated on-line solid phase extraction HPLC-MS/MS with peak focusing for the determination of ochratoxin A in wine samples

- Direct injection of adjusted pH wine samples was performed without any other sample pretreatments.
- A mixed mode ion exchange chromatography cartridge was employed as SPE column to perform a selective retention of OTA in wine.
- Peak-focusing strategy was used to concentrate the analyte on top of chromatographic column.
- A monolithic column was used to focus the ochratoxin A during elution from the SPE cartridge.
- Matrix-interferents were removed in the washing step avoiding matrix enhancement/suppression effects.

This study reports a fast and automated analytical procedure based on an on-line SPE-HPLC-MS/MS method for the automatic pre-concentration, clean up and sensitive determination of OTA in wine. The amount of OTA contained in 100 μL of sample (pH ≅ 5.5) was retained and concentrated on an Oasis MAX SPE cartridge. After a washing step to remove matrix interferents, the analyte was eluted in back-flush mode and the eluent from the SPE column was diluted through a mixing Tee, using an aqueous solution before the chromatographic separation achieved on a monolithic column. The developed method has been validated according to EU regulation N. 519/2014 and applied for the analysis of 41 red and 17 white wines. The developed method features minimal sample handling, low solvent consumption, high sample throughput, low analysis cost and provides an accurate and highly selective results.