4.1 Accurate elemental analysis of petroleum products and lubricants is necessary for the determination of chemical properties, which are used to establish compliance with commercial and regulatory specifications.

4.2 Inductively coupled plasma-atomic emission spectrometry is one of the more widely used analytical techniques in the oil industry for multi-element analysis as evident from at least twelve standard test methods (for example, Test Methods C1111, D1976, D4951, D5184, D5185, D5600, D5708, D6130, D6349, D6357, D7040, D7111, D7303, and D7691) published for the analysis of fossil fuels and related materials. These have been briefly summarized by Nadkarni (1).5

4.2.1 Determination of mercury and trace metals in crude oils using atomic spectroscopic methods is discussed in Guide D8056.

4.3 The advantages of using an ICP-AES analysis include high sensitivity for many elements of interest in the oil industry, relative freedom from interferences, linear calibration over a wide dynamic concentration range, single or multi-element capability, and ability to calibrate the instrument based on elemental standards irrespective of their elemental chemical forms, within limits described below such as solubility and volatility assuming direct liquid aspiration. Thus, the technique has become a method of choice in most of the oil industry laboratories for metal analyses of petroleum products and lubricants.

4.4 In addition to the ICP-AES standards listed in 2.2, a new ICP-MS standard, Test Method D8110, has been issued for analysis of distillate products for multi-element determination of Al, Ca, Cu, Fe, Pb, Mg, and K.