[Determination of Impurity Elements in Rosin with Inductively Coupled Plasma Mass Spectrometry]

An analytical method for the content determining of impurity elements in rosin was established. After being dissolved and diluted in ethanol, the rosin was analyzed directly with inductively coupled plasma mass spectrometry (ICP-MS). Some experiment conditions were optimized, such as the RF power, carrier gas flow, sample amount, and increase the temperature of plasma center channel, to improve the ionization efficiency. Proper oxygen concentration was added in plasma to make sure organic carbon been complete burned, resulting in carbon deposits eliminate and signal stable. Though equipment turn and isotopes selection can effectively eliminate interferences caused by oxide and doubly charged ions mass spectrums. A large amount of isobars and polyatomic ion interference were avoided. The collision reaction cell (CRC) technology was used to further eliminate the mass spectra interference, with He collision model and H2 reaction model, respectively. The results showed that detection limits of different impurity elements were within the range from 0.002 to 0.035 μg·g-1, and the recoveries of real added sample were between the range from 94.00% to 106.00%, and relative standard deviation is less than 3.34%. This method enables to detect rosin dissolved in ethanol directly and needs no special sample preparation equipment. This simple, fast and accurate approach provides us a new analysis method for the quality valuation of impurity elements in rosin.