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[Determination of the total amount of maleic acid and maleic anhydride in starch and its products by high performance liquid chromatography-tandem mass spectrometry].

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS) method was established for the determination of the total amount of maleic acid and maleic anhydride in starch and its products. The samples were extracted with 50% (v/v) methanol and hydrolyzed by alkaline, then analyzed by HPLC-MS/MS, and quantified with the external standard method. The mass spectrometry was operated with electrospray in negative ionization mode. The multiple reaction monitoring (MRM) mode was employed involving the transition of the precursor ion to two selected product ions, in which one pair was for quantification (m/z 115.0 > 71.1) and the other pair was for identification (m/z 115.0 > 27.1). The results indicated that no significant matrix effect was found for the spiked samples. The recoveries of maleic acid spiked in starch and its products were 80.2%-115.3% at spiked levels of 0.5-1,000 mg/kg. The relative standard deviations (RSDs) were less than 12% (n = 6). The limits of detection (LOD) and quantification (LOQ) were 0.1 and 0.5 mg/kg for maleic acid and maleic anhydride, respectively. The method is rapid, sensitive and reproducible for the determination of the total amount of maleic acid and maleic anhydride in starch and its products and shows great potential for routine analysis