The Use of Emulsions for the Determination of Mg, Al, Ti, V, Mn, Ni, Mo, Cd, and Pb in Oils by Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

Direct analysis of emulsified organic samples by inductively coupled plasma mass spectrometry (ICP-MS) reduces sample preparation time considerably and avoids the loss of volatile elements that can occur during ashing and heating stages of digestion. A simple procedure has been evaluated in terms of its analytical performance for the determination of trace elements in oil samples by ICP-MS. The technique is based on emulsifying the oil samples in water using Triton X-100 as surfactant. The oil samples introduced directly into the plasma in the form of oil-in-water emulsion. Optimization of the chemical conditions of the emulsion is reported. Method validation was performed by analysing Certified Reference Material CRM used oil HU1 for (SCP Science) and 1084a wear metals in lubricating oils (NIST). Satisfactory accuracy was obtained for Mg, Al, Ti, V, Mn, Ni, Mo, Cd and Pb in. The precision of the emulsion
 methodology was better than 8 % for most elements. Comparison of the method with acid digestion technique showed good agreement, validating the methodology and confirmed its applicability for routine analysis. The method detection limits for Mg, Al, Ti, V, Cr, Mn, Ni, Mo, Cd and Pb were 0.1, 0.06, 0.1, 0.06, 0.1, 0.02,
 0.03, 0.1, 0.03 ng/ml respectively, indicating that the method is performing well for organic matrices containing very low concentrations of trace elements.