Abstract
An accurate method for determining the concentration of lead in gasoline over the range 0.004–1500 µg g–1 is described. Tetraalkyllead compounds in the gasoline are converted into water-soluble species that are subsequently extracted into dilute nitric acid. Lead concentrations in the nitric acid extracts are determined using inductively coupled plasma mass spectrometry with a bismuth internal standard. The relative standard deviation of this method is ±2.4% for lead concentrations greater than 0.1 µg g–1. Studies with spiked samples and standard reference materials demonstrate excellent quantitative recoveries. The detection limit for lead in a 1 g gasoline sample is 0.004 µg g–1. Gasoline samples as large as 25 g can be extracted to enhance the accuracy and precision of low level (<0.1 µg g–1) determinations. Isotope ratio measurements on National Institute of Standards and Technology Standard Reference Material 1636a (Lead in Reference Fuel) yield a 206Pb/207Pb ratio of 1.2230 ± 0.0035 (95% confidence interval). The precision of these ratio measurements is suitable for performing both isotope dilution analyses as well as isotopic tracer studies.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have