| Abstract: | The recently developed isotopically edited internal standard approach for surface‐enhanced resonance Raman scattering (SERRS) based chemical quantification is extended to demonstrate multiplexed detection of four different isotopic variants of a single chromophore. More specifically, it is shown that rhodamine‐6G (R6G) with 0, 2, 4, or 6 deuterium substitutions may be reliably quantified in either two‐ or three‐component mixtures. Thus, one isotopic species of known concentration may be used as an internal standard to determine the concentrations of two other isotopic components in a mixture. The concentrations of isotopic R6G SERRS chromophores are determined using partial least squares calibration and shown to yield a predictive accuracy of about ± 10% of the total R6G concentration (over 1–50 nM concentration range). These results set the stage for the use of such isotopic variants as tags for the SERRS/SERS quantitation of mixtures containing proteins, peptides, and other compounds. Copyright © 2009 John Wiley & Sons, Ltd. |
