GAS-CHROMATOGRAPHIC MASS-SPECTROMETRIC DETERMINATION OF 4-(5)-METHYLIMIDAZOLE IN AMMONIA CARAMEL COLOR USING ION-PAIR EXTRACTION AND DERIVATIZATION WITH ISOBUTYLCHLOROFORMATE

A procedure for the gas chromatographic-mass spectrometric quantificat ion of 4-(5-)methylimidazole in ammonia caramel colours by using isobu tylchloroformate as derivatizing reagent has been developed. The use o f this reagent coupled to a previous ion-pair extraction of the compou nd with Bis-2-ethylhexylphosphate enabled routine determination of 4-( 5) methylimidazole with several advantages compared to others methods previously described. Examples of the analysis of some samples are pre sented as well as data on linearity, recovery and repeatability. Under the adopted conditions the limit of detection and the limit of quanti fication were 0.250 mg kg(-1) and 1 mg kg(-1), respectively. (C) 1997 Elsevier Science B.V.