Evaluation of direct sampling method for trace elements analysis in Chinese rice wine by ICP-OES

A direct sampling method by inductively coupled plasma optical emission spectrometry was evaluated for determining trace elements (Co, Cr, Cu, Fe, Mg, Mn, Se and Zn) in Chinese rice wine. The parameters of ICP (plasma power, nebulizer pressure and sampling speed) were optimized considering the complicated matrix. Both the nebulizer pressure and the sampling speed were kept low, and plasma power was set at a high value of 1.35 kW. The good accuracy was confirmed by the recovery test (> 95 %). The relative standard deviation was less than 5 %. Comparing with the dry ashing and wet ashing method, direct sampling showed to be fast, reliable and simple. The data of trace metals in Chinese rice wine were obtained: Co (0.088-0.106 mg/L), Cr (0.097-0.164 mg/L), Cu (0.085-0.126 mg/L), Fe (0.181-0.308 mg/L), Mg (0.179-0.311 mg/L), Mn (0.102-0.184 mg/L), Se (0.219-0.349) mg/L), and Zn (0.090-0.139 mg/L).