A rapid, sensitive and solvent-less method for determination of malonaldehyde in meat by stir bar sorptive extraction coupled thermal desorption and gas chromatography/mass spectrometry with in situ derivatization

RATIONALE The traditional methods for analysis of malonaldehyde (MDA), such as the thiobarbituric acid (TBA) assay, require strong acidity at high temperature for derivatization and lack specificity in analysis. Stir bar sorptive extraction (SBSE) coupled with thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) with in situ derivatization using pentafluorophenylhydrazine (PFPH) under mild conditions is an emerging technique for MDA analysis. METHODS MDA in meat was derivatized with PFPH at pH ~4 for 1 h at room temperature, forming a relative stable derivative of MDA-PFPH. The derivative of MDA-PFPH was simultaneously extracted using SBSE. Then, MDA-PFPH was thermally released and quantitatively analyzed by GC/MS in selected ion monitoring (SIM) mode. RESULTS The method of SBSE-TD-GC/MS for MDA analysis with in situ derivatization was optimized and validated with good linearity, specificity and limit of detection/quantification (LOD/LOQ). The method was successfully applied for analysis of MDA in raw and cooked meat (pork). CONCLUSIONS The SBSE-TD-GC/MS method was suitable to monitor and analyze MDA in meat samples at trace levels. The simple, sensitive and solvent-less method with moderated in situ derivatization can be applied for analysis of MDA in a wide variety of foods and biological samples.