Metals Analysis of Biodiesel Blends

Teresa Alleman, Earl Christensen, Lisa Fouts

Research output: NRELTechnical Report


The goal of this study was to compare metals analysis methods for biodiesel blends. Thirty-five B20 samples were collected from public stations and private fleets throughout the United States. All samples were analyzed for blend content and critical properties under the ASTM D7467 specification. Although not part of the specification, metals content, specifically Na, K, Ca, Mg, and P, is becoming an increasingly larger concern for industry. This study compared the metals content of the B20 samples using inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), and microwave plasma atomic emission spectroscopy (MP-AES) methods. All three techniques showed improvements over the current detection limits of 1 ppm for Na, K, Ca, and Mg, and 5 ppm for P. Some differences were found between methods, but agreement was generally acceptable at the very low levels present in these samples. The MP-AES technique showed good promise for future development for this type of analysis.
Original languageAmerican English
Number of pages37
StatePublished - 2019

NREL Publication Number

  • NREL/TP-5400-72341


  • B20
  • biodiesel
  • biodiesel blends
  • metals
  • microwave plasma atomic emission spectroscopy
  • MP-AES


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