Abstract: Graphite furnace atomic absorption spectrophotometry (GF-AAS) coupled with direct injection was used to establish a determination method for manganese in edible oil. The formation conditions of microemulsion and the effects of C12H25NaO4S concentration, ashing temperature and atomization temperature on absorbance were explored. Based on one-factor-at-a-time experiments, the optimal determination conditions were determined by orthogonal array design to be C12H25NaO4S concentration of 4.0 mg/mL, ashing temperature of 900 ℃ and atomization temperature of 1900 ℃. Under the optimal conditions, the content of manganese in edible oil was determined to be 37.49 ng/mL with a relative standard deviation of 1.86% and the detection limit of the method was 0.88 ng/mL. The average recovery rate for manganese in edible oil across three spike concentrations was 101.8% with a relative standard deviation of 3.27%. Therefore, this method is rapid, accurate and applicable without pollution and complex sample pretreatments.

Key words: microemulsion, direct injection, graphite furnace atomic absorption spectrophotometry, edible oil, manganese