High performance liquid chromatography-tandem mass spectrometry method for the determination of Nε- ( carboxymethyl) lysine in fried bread sticks

A method for the determination of Nε- ( carboxymethyl) lysine ( CML) content in fried bread sticks was developed using high performance liquid chromatography- tandem mass spectrometry ( HPLC- MS/MS) .Food samples were reduced by sodium borohydride, then hydrolyzed by hydrochloric acid and finally cleaned up by mixed cation exchange ( MCX) solid phase extraction cartridge.CML was remained on an Atlantis HILIC column.Methanol-water ( all containing 2mmoI /L ammonium acetate and 0.1% formic acid) were used as mobile phases.Tandem MS analysis was performed in multiple reactions monitoring ( MRM) mode using the electrospray positive ionization ( ESI +) method.D4- CML was used as internal standard substance, and the analysis time was12min.The average recoveries of CML for this method ranged from 89.5% to 99.1%, with the relative standard deviations ( RSD) were between 2.1% and 2.6%.The instrument detection limit was 1μg /L, and quantitation limit was3μg /L.Using this method, CML contents determined in 15 different sources fried bread sticks were 69.3 ± 8.2¹82.2± 3.1mg / ( kg protein) , and 5.3 ± 0.5¹5.4 ± 0.3mg / ( kg sample) .This method is simple, rapid, highly sensitive and accurate, and it is an effective method for further research on the generation mechanism of CML.