Application of pentafluorophenyl hydrazine on detecting 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone in irradiated chicken, pork and mangoes by gas chromatography-mass spectrometry

Abstract

A sensitive and reliable method for detection of irradiated chicken, pork and mangoes is described. The method involved a derivatisation treatment of irradiation markers—2-dodecylcyclobutanone (2-dDCB) and 2-tetradecylcyclobutanone (2-tDCB) with pentafluorophenyl hydrazine (PFPH) and detection by gas chromatography-mass spectrometry (GC-MS). Samples were first subjected to Soxhlet extraction with n-hexane and purified by passing through Florisil columns according to EN1785 method. Then, the extracted 2-dDCB and 2-tDCB were derivatised with PFPH in acidic buffer for 60 min at ambient temperature (∼25 °C). Identification of the derivatives was confirmed by the presence of two characteristic and dominant ion fragments at m/z 249 and [M-54], each within the specified retention time windows, and matching of the relative intensities of these ions with those of the standards under SIM mode. The relative standard deviation (%RSD) of the ion ratios of m/z 249 to that of [M-54] for all the food matrices under study (2.96–3.06 for PFPH-dDCB; and 2.69–2.83 for PFPH-tDCB, respectively) were ≤10%. Mean spike recovery of the derivatization process, with %RSD ≤20%, ranged from 68.6% to 71.4% and 57.9% to 70.8% for PFPH-dDCB and PFPH-tDCB respectively. The limits of detection (LODs) were estimated to be 0.01 μg/g. The present method was applicable to detect food samples that had received irradiation doses at 1–5 kGy. The quantity of equivalent 2-dDCB and 2-tDCB in the concerned foods was found to be proportional to the irradiated dose received.