Determination of residues of propamocarb in wine by liquid chromatography-electrospray mass spectrometry with direct injection

Abstract

A simple, sensitive and reliable liquid chromatography-mass spectrometry method with direct injection of diluted samples is reported for the determination of propamocarb residues in wine. Red and white wines were diluted 40- and 20-fold, respectively, using water. Liquid chromatography was performed with a mobile-phase gradient and detection was by electrospray mass spectrometry in a positive ionization mode. Propamocarb was detected as the protonated molecular species at m/z 189. Using matrix-matched calibrant solutions, a calibrated range equivalent to 0.05–2.0 mg kg⁻¹ in red and white wines and limits of detection of 0.025 mg kg⁻¹ for white wine and of 0.05 mg kg⁻¹ for red wine (0.00125 μg ml⁻¹ of sample solution injected) were readily achievable. Recovery of propamocarb hydrochloride from wine spiked before dilution was in the range 91–115%. The chromatograms were free of isobaric interferences. In a small wine survey (72 samples), no residues of propamocarb were detected above 0.1 mg kg⁻¹.

Keywords:

• wine
• liquid chromatography-mass spectrometry (LC/MS)
• pesticide analysis
• proamocarb
• fungicide residue