Abstract: Response surface methodology was employed to optimize three operating conditions for cadmium determination in table vinegar by graphite furnace atomic absorption spectrometry (GFAAS). On the basis of one-factor-at-a-time experiments, absorbance at 228.8 nm of tested samples was modeled against NH4H2PO4 concentration, ashing temperature and atomization temperature using a three-variable three-level Box-Benhnken experimental design combined with multiple regression analysis. The built regression model was analyzed by response surface methodology. It was found that the optimal determination conditions were 4.24 mg/mL NH4H2PO4 concentration, ashing 1013 ℃, and atomization at 1921℃. Under these conditions, the predicted values showed a good agreement with the experimental values. Using the optimized GFAAS method, the content of cadmium in a commercial vinegar sample was determined to be 0.188 μg/mL with a spike recovery of 98.76% and a relative standard deviation of 2.68%.

Key words: graphite furnace atomic absorption spectrometry (GF-AAS), table vinegar, cadmium, response surface methodology (RSM)