Determination of aliphatic amines by cation‐exchange chromatography with suppressed conductivity detection after solid phase extraction*

A sensitive method for the determination of underivatized aliphatic amines based on cation exchange chromatography coupled with suppressed conductivity detection scheme and solid phase extraction (SPE) procedure has been developed. A surface modified styrene divinylbenzene polymeric sorbent, based on a reversed‐phase (RP) and strong cation exchange (SCX) mixed mode was used as an active material for the SPE of amines. The conductometric capabilities of several aliphatic mono‐ and polyamines, expressed in terms of molar sensitivity (nS/μM), were determined. The LODs, obtained without the SPE treatment, ranged between 20 and 65 nM for putrescine and 2‐butylamine, respectively. The resulting calibration plots for the aliphatic amines were generally linear over about three orders of magnitude, with correlation coefficients >0.98. The LODs of amines decreased generally by one factor when SPE procedure, using BaCl₂/H₂SO₄ eluents, has been adopted. The proposed SPE procedure, seems to offer good results in terms of preconcentration, recoveries and cleanup of samples. The proposed methodology was successfully tested for the quantitative determination of some biogenic amines in beer and tuna.