ASTM D7455 Standard Practice for Sample Preparation of Petroleum and Lubricant Products for Elemental Analysis
3. Summary of Practice
3.1 This practice covers alternate ways of preparing a petroleum product or lubricant sample for elemental analysis measurements. The means of preparation of samples may vary from no special steps to extensive detailed procedures dependent on the sample matrix and the measurement technique to be used.
3.2 This practice may also be applicable to non-petroleum based biofuels. Work is underway to validate the applicability to these types of materials.
4. Significance and Use
4.1 Crude oil, petroleum, petroleum products, additives, and lubricants are routinely analyzed for their elemental content such as chlorine, nitrogen, phosphorus, sulfur, and various metals using a variety of analytical techniques. Some of these test methods require little to no sample preparation; some others require only simple dilutions; while others require elaborate sample decomposition before the product is analyzed for its elemental content.
4.2 Fairly often it can be shown that the round robin results by a co-operator are all biased with respect to those from other laboratories. Presumably, the failure to follow good laboratory practices and instructions in the test methods can be a causal factor of such errors. Afurther consequence is an unnecessarily large reproducibility estimate or the data being dropped from the study as an outlier.
4.3 Uniform practice for sample preparation is beneficial in standardizing the procedures and obtaining consistent results across the laboratories.
