The determination of B, Al, P, Fe, Ni, Cu, Zn, Cd and Pb in silicon powder by ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) using citric acid as the modifier was investigated. The influences of instrument operating conditions and slurry preparation on the ion signals were studied. A relatively low vaporization temperature of 1900 °C was used, which separated the analyte from the major matrix components that not only improved ion signals significantly but also alleviated the spectral interferences caused by 28Si29Si+, 28Si16O16O+, 28Si17O18O+ and 38Ar28Si+ on 57Fe+, 60Ni+, 63Cu+ and 66Zn+ determinations. The method has been applied to determine B, Al, P, Fe, Ni, Cu, Zn, Cd and Pb in a 99.999% pure silicon powder sample and four solar grade silicon powder samples using standard addition calibration methods. The concentrations that are in μg g−1 to sub μg g−1 levels were in good agreement with those of digested samples analyzed by pneumatic nebulization membrane desolvation ICP-MS. The precision between sample replicates was better than 9% with USS-ETV-ICP-MS technique. The method detection limit estimated from standard addition curves was about 8, 7, 9, 50, 9, 3, 7, 1 and 0.4 ng g−1 for B, Al, P, Fe, Ni, Cu, Zn, Cd and Pb, respectively, in original silicon samples.