RESUMO
A method for the determination of Na, Mg, Si, P, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Hg and Pb in castor oil after direct dilution with ethanol by inductively coupled plasma mass spectrometry (ICP-MS) was established. The sample was diluted by ethanol before ICP-MS determination. The condensation and deposition of high concentrations of carbon in mass cone interface and ion lens, which will decrease the sensitivity of element analysis, were avoided effectively by introducing O2 to plasma. The mass spectral interferences were eliminated by octopole reaction system (ORS). The matrix effects were calibrated to using Sc, Ge, Rh and Ir as internal standard elements. Au standard solution, which could form amalgam alloy with Hg, was dropped to eliminate the memory effect of Hg. The results show that the correlation coefficient for analyte is no less than 0.999 5, the detection limits is in the range of 0.06 - 20.1 ng x L(-1), the recovery is in the range of 990.4% - 110.2%, and the RSD is less than 4.8%. This method was very fast, simple and accurate to simultaneously analyze multi-elements in castor oil.
RESUMO
An octopole reaction system (ORS) inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of Mg, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Cd and Pb in edible phosphate. The sample was digested by HNO3 followed by dilution with ultrapure water, then the above 12 impurity elements in the solution were analyzed directly by ICP-MS The use of ORS can eliminate the interference of polyatomic ions dramatically. Sc, Y, In and Bi were used to correct the matrix interference and drift. The detection limits of the 12 elements are in the range of 0.004-0.362 microg x L(-1). This method is rapid, simple and applicable for the analysis of trace elements in edible phosphate.