Abstract:A high performance liquid chromatography (HPLC) method was developed for the determination of taurine in milk powder and liquid milk. The milk samples were dissolved in water, subjected to ultrasonic-assisted extraction for 10 min, precipitated with zinc acetate and potassium ferrocyanide, and centrifuged. The resultant supernatant was derivatized with phenyl isothiocyanate and triethylamine at room temperature for 1 h, before addition of n-hexane (to terminate derivatization) and standing (to allow phase separation). The lower layer solution was diluted with water and the obtained solution was filtered through a 0.22 μm microporous membrane. The filtrate was further separated using an amino acid analysis column (Diamonsil AAA, 4.6 × 250 mm, 5 μm) and a mobile phase for gradient elution with an aqueous sodium acetate solution (0.05 mol/L, pH=6.50) and acetonitrile / methanol (1/1, V/V). Quantification was performed using external standards. Good linearity was obtained in the concentration range of 5.0~40 μg/mL with correlation coefficients greater than 0.999, the limit of quantification as 5 mg/100 g (S/N≥10). At spiking levels of 5, 10 and 25 mg taurine /100 g r, the average recovery was in the range of 90%~108% with the relative standard deviation within 1.16%~2.24%. The results show that the analysis method established in this study is accurate and reliable, and meet the requirements for efficient analysis of taurine in milk powder and liquid milk. Compared with the GB method, this method is more suitable for effective detection of taurine in special diet milk powder.
