The Nizkorodov group has proposed a new approach for estimating concentrations of compounds in complex mixtures.

The work was done in collaboration with Dr. A. Laskin and Dr. J. Laskin from PNNL, using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). They showed that the observed ion sensitivities in HR-ESI-MS are correlated with the “adjusted mass,” defined as a product of the molecular mass and the H/C ratio in the molecule. The measurement can be done with the entire mixture without prior separation or use of calibration standards. This is highly advantageous for environmental samples as calibrations standards for the molecules of interest are rarely, if ever, available. This work was featured on the back cover of the Analytical Methods. Graduate student Tran Nguyen, who conceived and carried out this work, is currently a Stanback Postdoctoral Fellowship in Global Environmental Science at Caltech.