Estimation of Flame-Ionization Detector Relative Response Factors for Oligomers of Alkyl and Aryl Ether Polyethoxylates using the Effective Carbon Number Concept

The decreasing molar flame ionization detector response with the increasing length of the polyethylene oxide chain of three series of alkyl- and aryl-polyoxyethylene-trimethylsilyl ethers and a series of bis-trimethylsilylpolyoxyethylene ethers is described in terms of the effective carbon number (ECN) of each oligomer. When the ECN contribution of the -CH2-O-Si(CH3)3 group is assumed to be equivalent to 3.69 carbon atoms, the presence of each oxygen atom in the ethylene oxide chain is found to be equivalent to -0.41 ± 0.05 carbon atoms.