A Case Against Using Internal Standards for EPA Method TO-15 Involving Toxic Compounds in Ambient Air

Poster Presentation

Prepared by R. Bramston-Cook, E. Bramston-Cook
Lotus Consulting, 5781 Campo Walk, Long Beach, CA, 90803, United States


Contact Information: randy@lotusinstruments.com; 310-569-0128

ABSTRACT

Internal standards are frequently employed in many analytical methods, especially involving gas chromatography. Their selection and use are based on a number of factors related to the method and analytes of interest. Criteria for choice of internal standards are reviewed. The methods of addition of internal standards in the analysis and how their usefulness can be impacted are discussed. The primary application of internal standards in EPA Method TO15 is to correct for instability of the mass spectrometer. Inherent stability with a high performance mass spectrometer alleviates the need for complicating system operations with the addition of internal standards. Data are provided that demonstrate improved results without addition of internal standards.