Development of a new method for analyzing free aluminum ions (Al3+) in seafood using HPLC-ICP-MS

This paper presents a novel method for simultaneous online examination of free aluminum ions (Al3+) in seafood, using solid-phase extraction and high-performance liquid chromatography online with inductively coupled plasma mass spectrometry (SPE-HPLC-ICP-MS), without post-column reaction. The optimum conditions for chromatographic separation of Al3+ were achieved using an IonPac CS5A analytical column with an IonPac CG5A guard column. The mobile phase consisted of 0.040 mol/L LiOH, 0.0060 mol/L 2,6-pyridinedicarboxylic acid, and 0.090 mol/L CH3COOH (pH 4.7). The free Al3+ ions in seafood were extracted by shaking with the mobile phase at 70A degrees C for 2 h. SPE was conducted using an Oasis MCX, 3cc/60 mg, 30 mu m column, which was activated and equilibrated with 2 mL of methanol and 4 mL of deionized water before use. HCl (0.075 mol/L, 2 mL) was used to wash inorganic Al from the SPE column. The standard recoveries of Al3+ were all above 89% and the relative standard deviations were all below 5%. The proposed method was successfully used for the examination of Al3+ in seafood samples, and the results were similar to those obtained using the static equilibrium method.