DETERMINATION OF AMMONIA AND ALIPHATIC-AMINES IN FOOD BY ION CHROMATOGRAPHY WITH DOUBLE-CELL BULK ACOUSTIC-WAVE DETECTION

An ion chromatographic (IC) method with double-cell bulk acoustic wave (DCBAW) detection is described for determination of ammonia and low-m olecular-mass aliphatic amines in food. A 9 MHz AT-cut quartz crystal is used as the resonator. This detection technique provides high sensi tivity, good reproducibility, and wide work region. Its sensitivity is independent of background conductivity of the mobile phase in the ran ge 10-2700 mu S. Detection limits (peak = 3 delta) for NH4+, CH3NH3+, (CH3)(2)NH2+, and (CH3)(3)NH+ were 0.02, 0.05, 0.13, and 0.6 mu g/mL, respectively, Relative standard deviations for NH4+ CH3NH3+, (CH3)(2)N H2+, and (CH3)(3)NH+ were 0.7, 1.0, 0.8, and 1.2%, respectively. For I C analysis, the analytical column is a Shim-pack IC-C1 column and the mobile phase is 2.0 mmol/L nitric acid solution at a flow rate of 1,5 mL/min. Detection with DCBAW was compared with series bulk acoustic wa ve and conventional conductivity. The method was applied to analyses o f egg, fish, and cured meat.