Improved determination of taurine by high-performance anion-exchange chromatography with integrated pulsed amperometric detection (HPAEC-IPAD)

Abstract

The advantages of the high selectivity of high-performance anion-exchange chromatography (HPAEC) and the sensitive response of taurine at a gold electrode with integrated pulsed amperometric detection (IPAD) have been combined, in order to establish a new analytical method for its determination in real matrices. Potential-time settings of the potential waveform were optimized in order to get the highest amperometric response. The separation of taurine in milk samples was achieved using an alkaline eluent (100 mM NaOH) containing 1 mM Ba(OAc)₂ and a column temperature of 15 °C. The inherent merits of using a barium-modified eluent, in terms of taurine separation and detection, are demonstrated. The enhancement in sensitivity under these experimental conditions makes it suitable for taurine determination in milk. Indeed, this method allows high recovery of taurine and satisfies the necessary requirements with respect to accuracy, repeatability and sensitivity with a detection limit of 50 nmol/L, which corresponds to 2.5 pmol. The taurine content in milk samples of some common mammals was evaluated, including human milk. In goat’s milk, the taurine content ranged from 46 to 91 mg/L, whereas human and buffalo milk samples exhibited an average content of 18 mg/L and 23 mg/L, respectively.