Extraction with toluene and HPLC determination of aluminum in the form of an 8-hydroxyquinoline derivative

A reversed-phase high performance liquid chromatographic method for determination of trace amounts of aluminum has been developed using 8-hydoxylquinoline (8-HQ) as the precolumn reagent, and low-volatile toluene as the extraction reagent for the first time. The 8-HQ complex of Al was formed in weak basic medium and extracted to toluene. The separation was achieved on a PC8-10 column with the mobile phase of 40: 40: 20 methanol : acetyl acetate : 25 mmol/L lithium lactate (pH 8.0) at a flow rate of 1.0 mL/min. Excellent sensitivity was obtained by spectrophotometric detection at 390 nm and the detection limit was 0-08 ng. The response of Al is linear from 0.04 mug/mL to 1.0 mug/mL with a 10 muL injection. The extraction efficiency and precision of analyses were significantly improved. The proposed method has been successfully applied to the direct determination of Al in drinking and natural waters with the recoveries of 92.7-101.0%.